Building life cycle carbon emission calculation method based on finite element analysis

Abstract

The application discloses a building full life cycle carbon emission calculation method based on finite element analysis and belongs to the technical field of building carbon emission calculation. The method comprises the following steps: obtaining multi-source information in the full life cycle of a building, establishing a full life cycle dynamic finite element model mapped with building structure parameters; dividing time steps and performing physical field analysis and load working condition superposition calculation in each stage; dynamically correcting material loss factors, equipment energy consumption coefficients and waste output rates through superposition calculation results; inputting the corrected parameters into a carbon emission factor library for matching retrieval to generate a stage carbon emission intensity sequence; iteratively calculating until the carbon emission intensity change rate meets the convergence condition, and outputting total carbon emission equivalents. Through dynamic finite element modeling and multi-parameter correlation correction, the application realizes high-precision dynamic tracking of building full life cycle carbon emission.

Description

Technical Field

[0001] This invention relates to the field of building carbon emission calculation technology, specifically a method for calculating building carbon emissions throughout its entire life cycle based on finite element analysis. Background Technology

[0002] Calculating carbon emissions throughout a building's life cycle relies on a quantitative analysis of material and energy flows at each stage: building material production, construction, operation and maintenance, and demolition and recycling. Existing technologies typically calculate carbon emissions based on static bills of quantities and fixed energy consumption quotas. This method treats the building as a linear superposition of discrete stages, neglecting the continuous coupling effects between these stages over time. Existing solutions have significant shortcomings. Firstly, static calculation models use uniform material loss rates, equipment energy efficiency ratios, and waste production ratios throughout the entire lifecycle. This fails to reflect excessive material consumption caused by structural damage during construction, fluctuations in equipment energy consumption due to dynamic changes in the thermal performance of the building envelope, or the impact of demolition and crushing processes on waste particle size distribution and subsequent treatment methods. Secondly, conventional methods lack a mechanism to establish a dynamic mapping between structural mechanical response, thermophysical field evolution, and carbon emission factors. The parameters relied upon for the calculation remain constant throughout the entire lifecycle, resulting in homogenized carbon emission intensity at different time points. Consequently, the calculation results cannot accurately reflect the volatility and cumulative effects of a building's carbon footprint throughout its entire lifespan.

[0003] To address the above issues, it is necessary to solve how to incorporate the physical field evolution process of building structures throughout their entire life cycle into the carbon emission calculation parameter system, and how to achieve dynamic correlation correction of the three core parameters of material loss, equipment energy consumption, and waste generation, thereby improving the spatiotemporal resolution and accuracy of carbon emission calculations. Summary of the Invention

[0004] This invention provides a method for calculating carbon emissions throughout the entire life cycle of a building based on finite element analysis. The purpose is to construct a dynamic finite element model that maps to the building's structural parameters throughout the entire life cycle, and to feed back the results of physical field analysis and load condition superposition calculations at each stage of construction, operation, and demolition to the carbon emission calculation parameters in real time. This enables dynamic correction of material loss factors, equipment energy consumption coefficients, and waste production rates. Furthermore, a high-time-resolution sequence of stage carbon emission intensity is generated through an iterative convergence mechanism, ultimately outputting the total carbon emission equivalent throughout the building's entire life cycle.

[0005] To achieve the above objectives, this invention provides the following technical solution: This invention provides a method for calculating carbon emissions throughout the entire life cycle of a building based on finite element analysis. This method acquires building geometric information, material property information, construction process information, and equipment operation and maintenance information throughout the building's entire life cycle, and establishes a dynamic finite element model of the entire life cycle mapped to building structural parameters. In this process, the building geometric information is discretized into finite element mesh elements, and material property information is independently assigned to each element. Boundary condition mapping relationships for construction process information and equipment operation and maintenance information are established at the mesh element nodes, thereby constructing stiffness and mass matrices for calculating the structural stress field, temperature field, and displacement field. Preferably, the finite element mesh elements are discretized using hexahedral or tetrahedral elements, and the mesh is locally refined at interfaces where material properties change abruptly. As a technical solution of the present invention, after acquiring the above-mentioned multi-source information, it is further spatiotemporally registered. That is, the building geometric information is defined as a three-dimensional geometric entity in a global spatial coordinate system, and the material property information, construction process information, and equipment operation and maintenance information are discretized into material field data, construction field data, and operation and maintenance field data that correspond one-to-one with the finite element mesh elements of the three-dimensional geometric entity. Then, the data nodes with mismatched timestamps are aligned to the unified time axis of the full life cycle dynamic finite element model through a linear interpolation function, thereby ensuring that multi-source heterogeneous data are collaboratively calculated under a unified spatiotemporal reference.

[0006] Based on this full-lifecycle dynamic finite element model, the time steps are divided into construction, operation and maintenance, and demolition and recycling stages, and physical field analysis and superposition calculation of load conditions corresponding to each stage are performed. In the construction stage, concrete pouring loads, steel structure hoisting loads, and temporary support removal loads are sequentially applied to each finite element mesh element, and the structural stress and deformation response corresponding to each construction step is calculated. In the operation and maintenance stage, wind loads, temperature loads, and equipment vibration loads are simultaneously applied to each finite element mesh element, and the steady-state and transient heat conduction equations are solved to obtain the temperature gradient distribution at each time step of this stage. In the demolition and recycling stage, directional demolition loads and crushing mechanical impact loads are applied to each finite element mesh element in a time sequence to simulate the progressive degradation process of the structural stiffness matrix. Preferably, the time steps of the construction stage are divided according to the concrete pouring layer thickness or steel structure hoisting segment, and the time steps of the operation and maintenance stage are divided according to months or seasons, so that the simulation steps closely match the actual engineering progress.

[0007] Based on the superposition calculation results of the above physical field analysis and load conditions, the material loss factor, equipment energy consumption coefficient, and waste production rate in the dynamic finite element model of the entire life cycle are dynamically corrected, so that the model parameters can truly reflect the impact of performance degradation on carbon emissions at each stage. Specifically, the process of correcting the material loss factor includes: extracting the set of finite element mesh elements exceeding the material yield stress from the structural stress and deformation response during the construction stage and counting their volume; extracting the number of finite element mesh elements undergoing inelastic deformation during the progressive degradation of the structural stiffness matrix during the demolition and recycling stage; dividing the above volume and number by the total building volume to obtain the construction loss coefficient and demolition loss coefficient, and using them as the correction value of the material loss factor. The process of correcting the equipment energy consumption coefficient includes: extracting the temperature difference value of the inner and outer surfaces of the building envelope at each time step from the temperature gradient distribution during the operation and maintenance phase; using this temperature difference value as an input parameter, calling the preset HVAC equipment energy consumption simulation sub-model, and calculating the theoretical energy consumption value at that time step; comparing the theoretical energy consumption value with the preset benchmark energy consumption value, calculating the ratio factor between the two, and using it as the dynamic correction amount for the equipment energy consumption coefficient. Specifically, the HVAC equipment energy consumption simulation sub-model dynamically adjusts the start-stop frequency and power setpoint of the HVAC equipment within each time step according to the temperature gradient distribution during the operation and maintenance phase, achieving a refined simulation of the equipment's operating conditions. The process of correcting the waste production rate includes: identifying mesh element groups with sizes smaller than a preset crushing threshold from the finite element mesh element crushing response under the directional demolition load and crushing mechanical impact load during the demolition and recycling phase; calculating their total mass as the fine-particle waste mass, and dividing this mass by the total mass of all solid waste generated during the demolition and recycling phase to obtain the correction coefficient for the waste production rate.

[0008] The corrected material loss factor, equipment energy consumption coefficient, and waste output rate are input into a preset carbon emission factor library for matching and retrieval, generating a phased carbon emission intensity sequence bound to the time step. During the matching and retrieval, the material loss factor is used as an index to retrieve the unit carbon emission factor of various building materials such as cement, steel, and sand and gravel from the carbon emission factor library; the equipment energy consumption coefficient and waste output rate are used as a joint index to retrieve the unit carbon emission factor of various energy media such as diesel, electricity, and gasoline, as well as the unit carbon emission factor of various waste treatment methods such as landfill and incineration. The retrieved unit carbon emission factors of various building materials are multiplied by the preset usage of the corresponding materials, the unit carbon emission factors of various energy media are multiplied by the preset energy consumption, and the unit carbon emission factors of various waste treatment methods are multiplied by the waste output rate. All products are summed to generate a phased carbon emission intensity value bound to the current time step, and finally, the phased carbon emission intensity sequence is generated by arranging them in time step order.

[0009] The carbon emission intensity sequence for each stage is iteratively calculated until the rate of change of carbon emission intensity at each time step meets the convergence condition, and the total carbon emission equivalent for the entire building life cycle is output. During the iteration, the stage carbon emission intensity sequence generated in the current iteration is substituted into the dynamic finite element model for the entire life cycle, and the material loss factor, equipment energy consumption coefficient, and waste production rate are recalculated to generate the stage carbon emission intensity sequence for the next iteration. The absolute value of the difference between the stage carbon emission intensity values ​​at the same time step in two adjacent iterations is calculated and divided by the stage carbon emission intensity value at the current time step to obtain the rate of change of carbon emission intensity at that time step. When the rate of change of carbon emission intensity at all time steps is less than the preset convergence threshold, the iterative calculation is stopped, and all intensity values ​​in the stage carbon emission intensity sequence generated in the last iteration are summed to output the total carbon emission equivalent. Preferably, during the iterative calculation of the carbon emission intensity sequence, the life-cycle dynamic finite element model undergoes adaptive mesh refinement. This involves acquiring the physical field gradient differences between adjacent finite element mesh elements in the current iteration, including stress gradient differences, temperature gradient differences, or displacement gradient differences. It is then determined whether these gradient differences exceed a preset gradient threshold. If they do, the corresponding adjacent finite element mesh elements are tetrahedralized and refined. The refined mesh elements are then recombined to form an updated life-cycle dynamic finite element model for the next iteration. This method significantly improves the dynamic response capability and convergence accuracy of building life-cycle carbon emission calculations by establishing a dynamic coupling closed loop between structural mechanical response and carbon emission parameters.

[0010] The technical effects and advantages provided by the present invention in the above technical solution are as follows: By acquiring building geometry, material properties, construction techniques, and equipment operation and maintenance information throughout the building's entire life cycle, and establishing a dynamic finite element model that maps to the building's structural parameters, the finite element mesh elements not only bear geometric and material properties but also relate to the boundary conditions of construction techniques and equipment operation and maintenance. Based on this model, after dividing the time steps into construction, operation and maintenance, and demolition and recycling stages, concrete pouring loads, steel structure hoisting loads, and temporary support removal loads can be applied sequentially during the construction stage to calculate the structural stress and deformation response corresponding to each construction step. During the operation and maintenance stage, wind loads, temperature loads, and equipment vibration loads are applied simultaneously to solve the steady-state and transient heat conduction equations to obtain the temperature gradient distribution. During the demolition and recycling stage, directional demolition loads and crushing mechanical impact loads are applied in a time sequence to simulate the gradual degradation process of the structural stiffness matrix. Through the differential physical field analysis and load case superposition calculation of these three stages, carbon emission calculations no longer rely on static quotas but are directly related to the dynamic evolution of the actual structural mechanical and thermal states over time. From the structural stress and deformation response during the construction phase, sets of finite element mesh elements exceeding the material yield stress are extracted and their volumes are statistically analyzed. From the progressive degradation of the structural stiffness matrix during the demolition and recycling phase, the number of mesh elements undergoing inelastic deformation is extracted. Both are divided by the total building volume to obtain construction loss coefficients and demolition loss coefficients, which are used to correct the material loss factor. Simultaneously, from the temperature gradient distribution during the operation and maintenance phase, the temperature difference between the inner and outer surfaces of the building envelope at each time step is extracted. The theoretical energy consumption value is calculated using the HVAC equipment energy consumption simulation sub-model and compared with the baseline energy consumption value to obtain a scaling factor, which is used to dynamically correct the equipment energy consumption coefficient. From the mesh fragmentation response during the demolition and recycling phase, groups of mesh elements with sizes smaller than a preset fragmentation threshold are identified, and the mass of fine-particle waste is statistically analyzed. The proportion of this fine-particle waste to the total mass of solid waste is used as a correction coefficient for the waste production rate. These three types of parameters are independently extracted from the physical field calculation results and each forms a closed-loop correction path. This ensures that the material loss factor reflects the true accumulation of construction stress damage and inelastic deformation during demolition, the equipment energy consumption coefficient is adjusted in real time according to the dynamic changes in the thermal performance of the building envelope, and the waste output rate is directly quantified from the crushing simulation results, avoiding the calculation distortion caused by using fixed parameters throughout the entire life cycle in conventional methods. By iteratively calculating the carbon emission intensity sequence until the rate of change of carbon emission intensity at each time step meets the convergence condition, a self-consistent steady-state solution is formed between the corrected parameters and the carbon emission calculation results. The output total carbon emission equivalent for the entire building life cycle has higher spatiotemporal accuracy and dynamic tracking capability. Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0012] Figure 1 This is a flowchart of a building life-cycle carbon emission calculation method based on finite element analysis. Figure 2 This is a flowchart of the process for establishing a dynamic finite element model of the entire life cycle of a building; Figure 3 This is a flowchart of time step division and load case superposition calculation for dynamic finite element analysis throughout the entire life cycle; Figure 4 This is a flowchart illustrating the dynamic generation and iterative convergence of carbon emission intensity sequences throughout the entire life cycle of a building. Figure 5 This is a flowchart of the adaptive mesh refinement process for a dynamic finite element model throughout its entire lifecycle. Figure 6 These are the time-series curves of the maximum equivalent stress of the structure at each stage of the building's entire life cycle; Figure 7 It is the temperature difference between the inner and outer surfaces of the building envelope and the theoretical energy consumption curve of the HVAC equipment during the operation and maintenance phase; Figure 8 It is a curve showing the change in carbon emission intensity at each stage of the building's entire life cycle; Figure 9 This is a comparison chart of the stress gradient difference between adjacent finite element mesh elements and the yield stress threshold. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0014] See Figure 1This invention provides a method for calculating carbon emissions throughout the entire life cycle of a building based on finite element analysis. The method includes: acquiring building geometric information, material property information, construction process information, and equipment operation and maintenance information throughout the building's life cycle, and establishing a dynamic finite element model of the entire life cycle mapped to building structural parameters; based on the dynamic finite element model, dividing the time steps into construction, operation and maintenance, and demolition / recycling stages, and performing superposition calculations of physical field analysis and load conditions corresponding to each stage; dynamically correcting the material loss factor, equipment energy consumption coefficient, and waste production rate in the dynamic finite element model of the entire life cycle through the superposition calculation results of physical field analysis and load conditions; inputting the corrected material loss factor, equipment energy consumption coefficient, and waste production rate into a preset carbon emission factor library for matching and retrieval, generating a stage carbon emission intensity sequence bound to the time step; iteratively calculating the stage carbon emission intensity sequence until the carbon emission intensity change rate corresponding to each time step meets the convergence condition, and outputting the total carbon emission equivalent of the building's entire life cycle.

[0015] Example 1:

[0016] In specific implementation, please refer to Figure 2 This system acquires building geometry, material properties, construction techniques, and equipment operation and maintenance information throughout the building's entire lifecycle. Building geometry information originates from BIM models or CAD engineering drawings during the architectural design phase. This information is extracted and converted into three-dimensional point, line, and surface data containing the spatial coordinates and dimensions of components such as walls, columns, beams, slabs, and foundations. Material properties are obtained by reviewing material lists in design drawings and testing reports provided by material suppliers, including physical and mechanical parameters such as cement grade, steel grade, concrete strength grade, thermal conductivity, density, elastic modulus, Poisson's ratio, and yield strength. Construction techniques information is collected through construction organization design documents and construction logs, covering concrete pouring sequence, steel structure hoisting segment division, formwork support system layout, temporary support removal sequence, and construction machinery shift configuration. Equipment operation and maintenance information is provided by the building equipment management system or energy audit reports, including HVAC system operation schedules, lighting power density, elevator usage frequency, water supply and drainage equipment start-up and shutdown times, and hourly energy consumption data for each energy metering node.

[0017] After acquiring multi-source information, spatiotemporal registration is performed. The building's geometric information is defined in a global spatial coordinate system, forming a three-dimensional geometric entity. The global spatial coordinate system uses the building's base corner as the origin, the building's forward axis as the X and Y axes, and the vertical height as the Z axis. The three-dimensional geometric entity is described by boundary representation or constructed solid geometry, and its interior carries the partitioned domain of the subsequent finite element mesh. When discretizing the multi-source information into field data and mapping it to the unified time axis of the full-lifecycle dynamic finite element model, the application of the linear interpolation function is based on the actual correspondence between the time step division method of the full-lifecycle dynamic finite element model and the sampling frequency of the original data. The time steps of the construction phase are divided according to the thickness of the concrete pouring layer or the steel structure hoisting segment. The physical duration corresponding to each time step is determined by the planned construction period in the construction organization design document and the actual construction log records. The order of application of construction loads between adjacent time steps follows the established construction process. The duration of each process in this process is measured in working days or shifts. There are no sudden load jumps or abrupt changes in material properties during the transition between adjacent processes. Therefore, the changes in construction site data between adjacent time steps are continuous and gradual. The time step for the operation and maintenance phase is divided into months. Equipment operation and maintenance information is recorded hourly by the building equipment management system, recording hourly energy consumption data for each energy metering node. This data is then aggregated monthly by the energy audit report to form the monthly cumulative energy consumption value. The period length (in months) corresponding to the unified time axis operation and maintenance time step is much longer than the sampling period (in hours) of the original data. When aggregating hourly sampled data by monthly step, the hourly fluctuations within each month have been smoothed through monthly cumulative statistics. The discrete moments of the unified time axis correspond to the cumulative values ​​at the monthly boundaries. Linear interpolation performs a transitional mapping of the monthly cumulative values ​​between adjacent monthly boundaries, rather than directly interpolating the hourly high-frequency fluctuation sequence. The timestamps in the construction site dataset and the operation and maintenance site dataset originate from continuous monitoring records of the same building project at different stages. The time deviation between the data from each site is caused by clock recording errors in the construction log recording system and the building equipment management system. This time deviation, relative to the time steps of the construction and operation and maintenance phases (which are measured in days or months), does not affect the validity of the interpolation results within the accuracy requirements for carbon emission parameter calculation.

[0018] Material property information, construction process information, and equipment operation and maintenance information are discretized into field data that correspond one-to-one with finite element mesh elements of a three-dimensional geometric entity. The three-dimensional geometric entity is then meshed using finite element methods to obtain... Each grid cell is assigned a unique cell number. Material property information is mapped to a material field dataset that varies with spatial location, based on the material type of the component to which the cell belongs. ,in Indicates the first The number of each grid cell, This is a vector containing all material physical and mechanical parameters for this grid cell. Construction technology information is transformed into a time-series construction site dataset according to the construction schedule. , Indicates at time Apply to the Construction load identifiers and boundary condition states for each grid cell, corresponding to inactive cells. The current state is empty. Equipment operation and maintenance information is converted from equipment operation logs into a time-series operation and maintenance dataset. , Indicates at time Acting on the A set of operating parameters for each grid cell, including the intensity of the equipment heat source, the amplitude and frequency of the vibration load.

[0019] The timestamps in the material storage data, construction data, and operation and maintenance data are recorded by the actual acquisition system. The time intervals of the actual acquisition system may be uneven, and the sampling times of the three data sets may be asynchronous. A unified time axis is defined for the full life-cycle dynamic finite element model. This unified timeline covers the entire process from construction to demolition. The time step is pre-defined according to the phase divisions: the construction phase's time step is divided according to the thickness of the concrete pour or the time corresponding to the steel structure hoisting segment; the operation and maintenance phase's time step is divided by month. For data nodes in any type of field data whose timestamps do not fall on the discrete moments of the unified timeline, alignment is achieved using a linear interpolation function. In specific implementation, for the operation and maintenance field dataset... At time 10:00, a certain grid cell in the grid... a certain parameter value ,like Two adjacent discrete moments on the same time axis and Between, and the grid cell is in Time and The parameter value obtained from the original data record at any time is and Then the interpolated parameter value Calculated using the following formula:

[0020] in, To unify the timeline The baseline value is obtained after secondary sampling of the original data record value. To unify the timeline The baseline value is obtained after secondary sampling of the original data record value. To unify the time interval between two adjacent discrete moments on the time axis This represents the time offset between the original data timestamp and the previous discrete moment. When Exactly equal to At that time, take directly For the construction site dataset and material field dataset For the time-varying parts, the same linear interpolation function is used to map them to a unified time axis. After completing the time alignment of all field data, the material field data, construction field data, and operation and maintenance field data form a complete mapping on a unified finite element mesh element index and a unified time axis.

[0021] When establishing a dynamic finite element model for the entire life cycle, the building's geometric information is discretized into finite element mesh elements. The three-dimensional geometric entities corresponding to the building's geometric information are imported into the finite element preprocessing module. Hexahedral elements are used to map and mesh regular regions, while tetrahedral elements are used to perform free meshing of irregular or transitional regions. At interfaces with abrupt changes in material properties, such as the interface between a concrete beam and a masonry infill wall, or the interface between a steel column base and a concrete foundation, local mesh refinement is achieved by setting smaller mesh elements on both sides of the interface. The size of the refined mesh is no larger than half the initial mesh size in the adjacent region of the interface. Each finite element mesh element is independently assigned material property information from the discretized material field data, including elastic modulus, Poisson's ratio, density, thermal conductivity, specific heat capacity, and yield strength.

[0022] A boundary condition mapping relationship between construction process information and equipment operation and maintenance information is established at the nodes of the finite element mesh. Concrete pouring loads in the construction process information are converted into vertical surface pressures acting on the corresponding mesh unit nodes; steel structure hoisting loads are converted into concentrated forces applied to the hoisting point nodes; and temporary support removal loads are released by eliminating the corresponding node displacement constraints. Equipment vibration loads in the equipment operation and maintenance information are mapped to harmonic concentrated forces or nodal acceleration excitations acting on adjacent nodes based on the equipment installation location; wind loads are converted into nodal pressures based on the windward area and shape coefficient of the building surface unit nodes; and temperature loads are mapped to temperature boundary conditions applied to the building envelope unit nodes based on equipment heat dissipation information. Based on the above boundary condition mapping relationship, a set of nodal load vectors and constraint conditions is formed.

[0023] Based on the finite element mesh elements with assigned material properties and completed boundary condition mapping, stiffness and mass matrices are constructed to calculate the structural stress, temperature, and displacement fields. For the structural stress and displacement field analysis, the element stiffness matrix is ​​derived using the standard Galerkin finite element method with shape function interpolation within the elements. and unit mass matrix ,in For a unit volume domain, The strain-displacement matrix, For the elastic constitutive matrix, Material density allocated to the unit The shape function matrix is ​​used. The overall stiffness matrix and overall mass matrix are obtained by assembling the stiffness and mass matrices of all elements according to their node numbers. For temperature field analysis, the thermal conductivity stiffness matrix is ​​constructed. and heat capacity matrix The thermal conductivity stiffness matrix is ​​integrated from the element thermal conductivity, convective heat transfer coefficient, and radiative heat transfer coefficient according to the boundary conditions, while the heat capacity matrix is ​​integrated from the element specific heat capacity and density. Together, they constitute the coefficient matrix required for the transient heat conduction equation. Thus, the establishment of the full-life-cycle dynamic finite element model is complete.

[0024] Example 2:

[0025] In specific implementation, please refer to Figure 3 Based on the established full-life-cycle dynamic finite element model, the time steps for the construction, operation and maintenance, and demolition and recycling phases are divided. The time steps for the construction phase are determined according to the material properties and technological characteristics of the construction object. For cast-in-place concrete structures, the time steps for the construction phase are divided according to the thickness of the concrete pouring layers. The height of a single layer is obtained from the layered pouring records in the construction plan, typically ranging from 2.8 meters to 4.2 meters. The pouring and curing process of each layer of concrete is mapped to a time step, the physical duration of which covers the time interval from the start of pouring to reaching the demolding strength. For steel structure systems, the time steps for the construction phase are divided according to the steel structure hoisting segments. One hoisting segment corresponds to a hoisting unit in the construction schedule, which includes several trusses or steel columns. The time step corresponding to this hoisting segment is determined by the hoisting shift quota and actual construction logs. Within the time step, the hoisting, temporary connection, and measurement correction of the segment are completed. The construction phase begins when the foundation pad is poured or the first steel column is hoisted, and ends when the main structure is capped and passes structural acceptance.

[0026] The operation and maintenance phase is divided into monthly time steps. The total duration of the operation and maintenance phase is converted into a monthly sequence, with each complete calendar month between the transitions of two adjacent months constituting one operation and maintenance time step, for a total of 12 operation and maintenance time steps throughout the year. If there are significant seasonal differences in the climate data of the building's location, the operation and maintenance phase time steps can also be divided according to the season, dividing the year into the heating season, cooling season, and transition season, with each season constituting one operation and maintenance time step. The heating season corresponds to consecutive months with an average monthly temperature below 5°C, the cooling season corresponds to consecutive months with an average monthly temperature above 26°C, and the transition season comprises the remaining months. This division method is determined by consulting the average monthly temperature data of the local meteorological station for the past ten years. The demolition and recycling phase is divided into time steps according to the daily progress of construction demolition, with each calendar day constituting one time step, starting from the first day of demolition machinery entering the site and causing structural damage, until the last batch of solid waste is transported away from the site.

[0027] After completing the phase division and time step setting, the physical field analysis and load case superposition calculations corresponding to each phase are performed. During the construction phase, the element birth and death technique is used to sequentially apply concrete pouring loads, steel structure hoisting loads, and temporary support removal loads to each finite element mesh element. In the finite element solver, in the initial state, the stiffness matrix and mass matrix of all finite element mesh elements in the full-life-cycle dynamic finite element model are multiplied by a minimum factor, which is set to a value of... This ensures that all finite element mesh elements are excluded from structural stress and deformation calculations. Following the construction sequence, the finite element mesh sets within the corresponding concrete pouring layer thickness or steel structure hoisting segment are activated step-by-step. The activation operation restores the stiffness and mass matrices of the involved finite element mesh elements to their original calculated values. Within the same time step, concrete pouring loads are applied to the newly activated finite element mesh elements. These loads include the vertical distributed load generated by the self-weight of the newly poured concrete and the horizontal distributed load generated by the lateral pressure of the flowing concrete. The magnitude of the vertical distributed load is the product of the concrete density and the pouring layer thickness, while the horizontal distributed load is determined according to the equivalent static pressure within the vibration radius. If the time step involves a steel structure hoisting segment, a steel structure hoisting load is applied to the nodes of the hoisting segment. This load is applied as a concentrated force to the node where the lifting lug is located. The magnitude of the concentrated force is equal to the self-weight of the hoisting segment multiplied by a dynamic amplification factor, which ranges from 1.15 to 1.35 depending on the type of hoisting machinery. Within the same construction time step or the immediately following time step, once the concrete strength reaches the design demolding strength or the steel structure connection forms a stable system, the temporary support removal load is applied. This temporary support removal load is achieved by removing the displacement constraints of the removed support nodes in one go and releasing the internal forces of the supports as reverse nodal forces. The process of removing constraints and applying reverse nodal forces is completed within one incremental step. All time steps are traversed in the construction sequence, and the structural static equilibrium equations are solved at each time step to obtain the structural stress and deformation response corresponding to each construction step. The structural stress includes the normal stress and shear stress components at the element integration points, and the deformation response includes the displacement vectors of each node.

[0028] During the operation and maintenance phase, wind load, temperature load, and equipment vibration load are simultaneously applied to each finite element mesh element. Steady-state and transient heat conduction equations are solved to obtain the temperature gradient distribution at each time step during the operation and maintenance phase. Wind load is applied based on the projected windward area and shape coefficient of the finite element mesh element facing outwards. The shape coefficient is selected from the shape coefficient table according to the building's shape: 0.8 for the windward side, -0.5 for the leeward side, and -0.7 for the side sides. The wind load direction is along the prevailing monthly wind direction corresponding to that time step. Wind speed is obtained from the monthly average wind speed data of the local meteorological station, converted to basic wind pressure, and multiplied by the gust coefficient to obtain the nodal pressure value. Temperature load is defined by the wall thermal boundary conditions, including solar radiation heat absorption flux, indoor and outdoor air convection heat transfer, and nighttime sky radiation heat dissipation. The solar radiation heat flux was calculated using the Ashclair model. The solar altitude and azimuth angles were determined based on geographical location and month, and the instantaneous radiation intensity projected onto the surfaces of the building envelope units facing each direction was calculated. Indoor air temperature was taken as the HVAC design temperature, ranging from 18°C ​​to 22°C during the heating season and from 24°C to 26°C during the cooling season. Outdoor air temperature was taken as the monthly average temperature and diurnal temperature range, serving as the boundary conditions for convective heat transfer. Equipment vibration loads were borne by the finite element mesh nodes within the equipment room housing rotating or reciprocating machinery. The equipment vibration loads were simplified to a harmonic concentrated force with a defined frequency. The excitation frequency was converted from the equipment nameplate rotation speed, and the force amplitude was determined based on the equipment weight and the vibration intensity standard ISO 10816. Within each operation and maintenance time step, the transient heat conduction equation was discretized over time. Transient propagation was performed using a daily step size within a one-month time step to solve for the temperature field at each daily step, thereby extracting the temperature gradient distribution over the entire operation and maintenance time step. Simultaneously, the thermal strain caused by the temperature field is superimposed on the total strain to calculate the structural stress, thereby obtaining the structural mechanical response under the combined effects of thermal, wind, and mechanical vibration effects during the operation and maintenance time step.

[0029] During the demolition and recovery phase, directional demolition loads and mechanical impact loads are applied to each finite element mesh element in a time-series manner to simulate the progressive degradation process of the structural stiffness matrix. At the start of the demolition and recovery phase, the finite element mesh elements in the full-life-cycle dynamic finite element model are in a state of full stiffness. According to the demolition process schedule, each day is taken as a time step, within which the demolition advancement direction and the range of the crushing operation surface are determined. Directional demolition loads that have not yet appeared at the previous moment are applied to the finite element mesh elements within the demolition operation surface. The directional demolition loads are divided into two categories according to the demolition method: if hydraulic breakers are used for demolition, the directional demolition load is equivalent to a triangular impact pulse acting on the element surface, with the peak pulse value being the product of the breaker's working pressure and the chisel area, and the pulse duration being 5 to 10 milliseconds; if controlled blasting is used for demolition, the directional demolition load is equivalent to an exponentially decaying pressure time history acting on the element nodes around the blast hole, with the peak pressure calculated based on the explosive heat of combustion and the charge amount. For large structural members that have undergone directional dismantling, further mechanical impact loads are applied. These loads simulate the squeezing and impact of jaw crusher or impact crusher teeth on concrete fragments, simplifying the load as a uniformly distributed pulse sequence acting on the corresponding finite element mesh group during the dismantling stage. Simultaneously with the directional dismantling load and the mechanical impact load, the structural stiffness matrix is ​​updated based on the element damage variables. The progressive degradation process reduces the elastic modulus of finite element mesh elements whose equivalent plastic strain exceeds the failure threshold after being subjected to the load to their original elastic modulus. This process is implemented by removing these finite element mesh elements from the assembly of the overall stiffness matrix and mass matrix before the next time step. The removed finite element mesh elements are considered broken and detached and enter the waste production statistics stage. The dismantling and recycling stage is advanced step by step, and the configuration changes of the structural stiffness matrix before and after degradation at each time step are recorded until all finite element mesh elements are removed, completing the simulation of the progressive degradation process of the structural stiffness matrix.

[0030] See Figure 6 In the figure, the horizontal axis represents the time step, and the vertical axis represents the maximum equivalent stress of the structure (in MPa). The legend distinguishes the structural stress change trends in the three major stages: the construction stage (solid line), the operation and maintenance stage (dashed line), and the demolition and recycling stage (dotted line).

[0031] During the construction phase, the maximum equivalent stress of the structure showed a monotonically increasing trend over time, gradually rising from an initial 0 MPa to approximately 120 MPa. This reflects the gradual establishment of the structure's bearing capacity as the concrete pouring layers thickened or the steel structure hoisting segments were activated. The stable and continuous stress growth during the construction phase indicates that the stiffness and mass matrices of the newly activated mesh elements in the finite element model have recovered to their original calculated values, and the load application was reasonable.

[0032] During the operation and maintenance phase, the maximum equivalent stress of the structure fluctuated within the range of approximately 100 to 140 MPa, exhibiting periodic fluctuations with a significantly larger amplitude compared to the construction phase. This fluctuation corresponds to the physical field analysis results under the combined effects of collected equipment operation and maintenance information, wind load, and temperature load, reflecting the dynamic impact of HVAC system operation and ambient temperature changes on structural stress. The operation and maintenance phase is divided into monthly time steps, and the periodic fluctuations reflect the combined effects of seasonal climate change and equipment operation and maintenance load.

[0033] During the demolition and recycling phase, the maximum equivalent stress of the structure showed a continuous downward trend, gradually decreasing from approximately 120 MPa to near 0 MPa. This indicates that with the application of directional demolition loads and mechanical impact loads, the structural stiffness matrix gradually degraded, a large number of mesh elements failed and were removed, and the overall load-bearing capacity of the structure was rapidly lost. The time step of the demolition and recycling phase was divided into natural days, and the smooth decline of the curve reflects the gradual failure characteristics of the demolition process.

[0034] Overall, the trend of the maximum equivalent stress in the figure clearly divides the three stages of the entire life cycle, and the stress change characteristics in each stage are consistent with the time step division, physical field analysis and load case superposition calculation described in Example 2, which fully demonstrates the accurate capture of the stress state of the building structure in the entire life cycle by the dynamic finite element model.

[0035] Example 3:

[0036] In practical implementation, the material loss factor in the full-life-cycle dynamic finite element model is dynamically corrected by superimposing the results of physical field analysis and load conditions. From the structural stress and deformation response obtained during the construction phase, a set of finite element mesh elements exceeding the material yield stress is extracted. The calculation results for each time step of the construction phase are iterated, and the equivalent stress value at the integration point of each finite element mesh element is read. The von Mises yield criterion is used for judgment; when the equivalent stress value of a finite element mesh element exceeds the yield stress value in the material property information assigned to that finite element mesh element, that finite element mesh element is marked as a yield element. After traversing all time steps of the construction phase, duplicate yield elements marked at any time point in the construction phase are removed to form a set of finite element mesh elements exceeding the material yield stress. The volume of the set of finite element mesh elements exceeding the material yield stress is calculated. For hexahedral elements, the volume is obtained by the Gaussian integral of the Jacobian matrix determinant at the integration point; for tetrahedral elements, the volume is calculated by the nodal coordinate determinant. The total volume of the yielding elements is obtained by summing the volumes of all yielding elements in the set.

[0037] The number of finite element mesh elements undergoing inelastic deformation is extracted during the progressive degradation of the structural stiffness matrix in the demolition and recycling phase. At each time step in the demolition and recycling phase, after applying directional demolition loads or mechanical impact loads to the finite element mesh elements, the equivalent plastic strain increment of each finite element mesh element is calculated. The equivalent plastic strain increment is solved using a radial back-mapping algorithm, with an isotropic hardening von Mises plasticity model as the constitutive model and the associated flow rule as the flow rule. After convergence at a certain time step, if the equivalent plastic strain of a finite element mesh element increases from zero in the previous time step to a value greater than zero, or continues to increase from its existing plastic strain state, then that finite element mesh element is classified as undergoing inelastic deformation. The number of duplicate finite element mesh elements classified as undergoing inelastic deformation across all time steps in the demolition and recycling phase is counted as the total number of finite element mesh elements undergoing inelastic deformation.

[0038] The construction loss coefficient and demolition loss coefficient are obtained by dividing the volume of the finite element mesh set exceeding the material yield stress and the number of finite element mesh elements undergoing inelastic deformation by the total building volume, respectively. The total building volume is obtained by summing the volumes of all finite element mesh elements in the full-life-cycle dynamic finite element model; this volume is a fixed value after the model is established. Construction loss coefficient. The total volume of the yielding element Divide by the total building volume The calculated dismantling loss coefficient The number of finite element mesh elements that undergo inelastic deformation The corresponding total volume Divide by the total building volume The calculation yielded, where This is the volume value obtained by summing the volumes of each element in the finite element mesh set that has undergone inelastic deformation. In specific implementations, the correction value of the material loss factor is determined using the following formula. :

[0039] in, This is a correction value for the material loss factor, dimensionless, and ranging from 0 to 1; The volume of a finite element mesh set exceeding the material's yield stress, expressed in cubic meters. The volume of the finite element mesh set that undergoes inelastic deformation, in cubic meters; The total building volume is expressed in cubic meters. The construction loss weighting coefficient is set to 0.5. This value is based on the average contribution ratio of material loss during the construction phase to the total material loss throughout the entire life cycle. This average contribution ratio is obtained by averaging the historical construction loss statistics of similar buildings. The weighting factor for dismantling losses is set to 0.5. Confirmed. Correction value for material loss factor. After obtaining the results, the material loss factor currently stored in the full life cycle dynamic finite element model is updated to the original material loss factor plus the corrected material loss factor value. The weighted average is calculated, with each weight set to 0.5.

[0040] Dynamically correct equipment energy consumption coefficient. Extract the temperature difference between the inner and outer surfaces of the building envelope at each time step from the temperature gradient distribution during the operation and maintenance phase. In the temperature field calculation results for each operation and maintenance time step, the building envelope includes exterior walls, windows, roof, and basement slab. Temperature values ​​are extracted for both inner and outer surface nodes of the envelope. The inner surface temperature is represented by the average temperature of all nodes on the inner wall of the envelope, and the outer surface temperature is represented by the average temperature of all nodes on the outer wall of the envelope. The temperature difference between the inner and outer surfaces is taken as the absolute value of the difference between the average outer surface temperature and the average inner surface temperature. Using this temperature difference as an input parameter, a preset HVAC equipment energy consumption simulation sub-model is called to calculate the theoretical energy consumption value at that time step. The HVAC equipment energy consumption simulation sub-model dynamically adjusts the start / stop frequency and power setpoint of the HVAC equipment within each time step based on the temperature gradient distribution during the operation and maintenance phase. The HVAC equipment energy consumption simulation sub-model internally employs the transfer function method to construct a thermal response model of the building envelope. The transfer function method treats the building envelope as a linear time-invariant system. Input parameters include hourly air temperatures on both sides of the building envelope, solar radiation heat gain, internal lighting and equipment heat dissipation density, and personnel density. The output is the hourly heating and cooling load. At the beginning of each operation and maintenance time step, the HVAC equipment energy consumption simulation sub-model determines the hourly output distribution of the HVAC equipment for that month based on historical meteorological parameters and the actual internal heat source change trend of the previous month, and calculates the theoretical energy consumption value accordingly. The theoretical energy consumption value includes the combined electricity or fuel consumption equivalent of chiller energy consumption, heater energy consumption, fan energy consumption, and water pump energy consumption, expressed in kilowatt-hours or joules.

[0041] The theoretical energy consumption value is compared with the preset benchmark energy consumption value to calculate the scaling factor. The preset benchmark energy consumption value is the monthly energy consumption value of the same month obtained from the full-year simulation of the building energy consumption design simulation software EnergyPlus under the design conditions. This benchmark energy consumption value is obtained from the building energy consumption simulation report during the design phase and is a fixed reference value. Scaling factor By using theoretical energy consumption values Divide by the baseline energy consumption value get, Scale factor As a dynamic correction factor for the equipment energy consumption coefficient, the currently stored equipment energy consumption coefficient in the full life cycle dynamic finite element model is updated to the original equipment energy consumption coefficient and scaling factor. The product of the product. If the scaling factor A value greater than 1 indicates that actual operating conditions lead to energy consumption exceeding the design baseline, and the equipment energy consumption coefficient is adjusted upwards; if the scaling factor is greater than 1, it indicates that actual operating conditions lead to energy consumption exceeding the design baseline, and the equipment energy consumption coefficient is adjusted upwards. If the value is less than 1, the energy consumption coefficient of the equipment will be reduced.

[0042] The waste production rate is dynamically adjusted. From the finite element mesh element crushing response under directional demolition loads and mechanical impact loads during the demolition and recycling phase, mesh element groups with sizes smaller than a preset crushing threshold are identified. At each time step during the demolition and recycling phase, when a finite element mesh element is removed from the overall stiffness matrix assembly due to equivalent plastic strain exceeding the failure threshold, the position coordinates of all nodes of the removed finite element mesh element at the time of removal are extracted. The characteristic size of the finite element mesh element under the current deformation configuration is calculated. The characteristic size is taken as the diameter of the circumscribed sphere of the finite element mesh element, obtained by calculating the maximum Euclidean distance between the node coordinates of the finite element mesh element. The preset crushing threshold is set according to the particle size classification standard of aggregate recycling technology, referring to the boundary particle size between coarse and fine aggregates in recycled concrete, and the preset crushing threshold is set to 4.75 mm. If the characteristic size of a finite element mesh element is less than 4.75 mm, the finite element mesh element is classified into the mesh element group with a size smaller than the preset crushing threshold. The total mass of the grid cell group whose size is smaller than the preset crushing threshold is calculated. The mass of a single finite element grid cell is obtained by multiplying the volume of the finite element grid cell by the density in its assigned material property information. The mass of all single finite element grid cells belonging to the grid cell group is summed to obtain the mass of fine-particle waste.

[0043] The correction factor for the waste production rate is obtained by dividing the mass of fine-grained waste by the total mass of all solid waste generated during the demolition and recycling phase. The total mass of all solid waste generated during the demolition and recycling phase is the sum of the masses of all finite element mesh elements removed from the overall stiffness matrix assembly across all time steps of the demolition and recycling phase. This sum is accumulated after all time steps of the demolition and recycling phase have been completed. (The correction factor for the waste production rate is...) Mass of fine-particle waste Divide by the total mass of all solid waste Calculations show that The currently stored waste production rate in the full lifecycle dynamic finite element model is updated to the original waste production rate plus a waste production rate correction factor. The weighted average is calculated, with each weight set to 0.5.

[0044] See Figure 7 In the graph, the horizontal axis represents the monthly sequence of the operation and maintenance phase, covering the entire time step of this phase; the left vertical axis represents the temperature difference between the inner and outer surfaces of the building envelope, in degrees Celsius, ranging from approximately -5°C to 35°C; the right vertical axis represents the theoretical energy consumption of the HVAC equipment, in kilowatt-hours, ranging from approximately 2000 kWh to 18000 kWh. In the legend, the solid line with dots represents the temperature difference between the inner and outer surfaces of the building envelope, and the dashed line with squares represents the theoretical energy consumption of the HVAC equipment.

[0045] The curves show that the temperature difference between the inner and outer surfaces of the building envelope exhibits a clear periodic fluctuation across months, with peak temperatures exceeding 25°C multiple times. The temperature difference between peaks and troughs varies considerably, and the lowest temperature difference occasionally shows a negative value. This indicates that the inner surface temperature approaches or reverses in certain months, reflecting the complexity of the actual climate conditions and the thermal response of the building envelope. The theoretical energy consumption curve for HVAC equipment generally shows a synchronous trend with the temperature difference curve, with peak energy consumption corresponding to near-peak temperature difference values. The maximum peak energy consumption is close to 17,000 kWh, while the lowest trough energy consumption is around 3,000 kWh, indicating that changes in the temperature difference of the building envelope directly affect the energy load of the HVAC system.

[0046] Both the temperature difference curve and the energy consumption curve exhibit monthly cyclical patterns, reflecting the significant impact of seasonal variations on the building's thermal environment and equipment energy consumption during the operation and maintenance phase. No significant abrupt changes were observed, indicating that the physical field analysis and energy consumption simulation sub-model provide relatively stable predictions for the building envelope's thermal response and HVAC equipment energy consumption. Slight deviations in the peak and trough heights of the two curves at multiple time points may be caused by changes in equipment control strategies or internal heat sources. Overall, the temperature difference fluctuation range is concentrated between 0℃ and 30℃, and the HVAC equipment energy consumption shows an upward trend with increasing temperature difference, verifying the rationality of dynamically correcting the equipment energy consumption coefficient based on temperature gradient distribution in Example 3.

[0047] This figure specifically reflects the time evolution relationship between the temperature difference data of the inner and outer surfaces of the building envelope extracted through temperature field calculation during the operation and maintenance phase in Example 3 and the theoretical energy consumption value calculated by calling the energy consumption simulation sub-model of HVAC equipment. It provides key input parameters and verification basis for dynamically correcting the equipment energy consumption coefficient.

[0048] Example 4:

[0049] In specific implementation, please refer to Figure 4The dynamically corrected material loss factor, equipment energy consumption coefficient, and waste output rate are input into a pre-defined carbon emission factor database for matching and retrieval, generating a phased carbon emission intensity sequence bound to a time step. The pre-defined carbon emission factor database is a relational database, storing three types of carbon emission factor data tables: building material carbon emission factor table, energy medium carbon emission factor table, and waste treatment carbon emission factor table. The building material carbon emission factor table uses building material type and material loss factor range as a joint primary key. The building material type field enumerates values ​​including cement, steel, sand and gravel, glass, wood, insulation materials, waterproofing materials, etc. The material loss factor range field is divided into 20 ranges with a step size of 0.05: [0,0.05), [0.05,0.10), ..., [0.95,1.00]. Each record stores the unit carbon emission factor of the corresponding building material type under the corresponding material loss factor range, in kilograms of carbon dioxide equivalent per ton. The energy medium carbon emission factor table uses energy medium type as the primary key. The enumerated values ​​for energy medium type include diesel, electricity, gasoline, natural gas, and coal. Each record stores the unit carbon emission factor for the corresponding energy medium, in kilograms of CO2 equivalent per kilowatt-hour or kilograms of CO2 equivalent per kilogram. The waste treatment carbon emission factor table uses waste treatment method and waste production rate range as the composite primary key. The enumerated values ​​for waste treatment method include landfill and incineration. The waste production rate range field is divided in the same way as the material loss factor range field. Each record stores the unit carbon emission factor for the corresponding treatment method and waste production rate range, in kilograms of CO2 equivalent per ton.

[0050] Using material loss factors as an index, the unit carbon emission factor for various building materials is retrieved from the carbon emission factor database. The value of the material loss factor comes from the current correction value stored in the full life cycle dynamic finite element model, and the decimal part of the material loss factor is rounded to fall within a certain material loss factor range. The types of building materials are determined by the material items in the project budget list, and a search is performed once for each type of material. The range of material loss factors and the type of building material are used as query conditions to match the unit carbon emission factor of that building material in the building material carbon emission factor table. In practice, if a complete match to the corresponding range cannot be found, the record corresponding to the nearest range is used.

[0051] Using equipment energy consumption coefficient and waste output rate as a joint index, the system retrieves the unit carbon emission factor for various energy media and the unit carbon emission factor for various waste treatment methods from the carbon emission factor database. The equipment energy consumption coefficient is derived from the current dynamic correction value stored in the full life-cycle dynamic finite element model. This value is directly used as a search condition to locate the corresponding record in the associated field of the energy media carbon emission factor table, with separate queries for different energy media types. The waste output rate is derived from the current corrected waste output rate stored in the full life-cycle dynamic finite element model, and its interval is determined in the same way as the material loss factor interval. Using the interval of the waste output rate and the waste treatment method as joint query conditions, the system retrieves the unit carbon emission factor for landfill treatment and incineration treatment from the waste treatment carbon emission factor table.

[0052] The unit carbon emission factor of each type of building material is multiplied by the preset usage of the corresponding material. For cement, the preset usage is the total mass of cement in the concrete mix proportion for all concrete pours during the construction phase, obtained from the mix proportion report in the construction organization design document. For steel, the preset usage is the total mass of steel reinforcement in all steel structure hoisting segments and reinforced concrete components in the building geometry information, obtained from the steel reinforcement list. For sand and gravel, the preset usage is the total mass of sand and gravel aggregate in all concrete, masonry, and mortar. The unit carbon emission factor of each type of energy medium is multiplied by the preset energy consumption. The preset energy consumption is the fuel and electricity consumption of construction machinery during the construction phase, the sub-item electricity consumption of HVAC, lighting, elevators, etc. during the operation and maintenance phase, and the fuel and electricity consumption of crushing machinery during the demolition and recycling phase, as recorded in the energy audit report or building equipment management system. Energy consumption is summarized separately by energy medium type. The unit carbon emission factor of each waste treatment method retrieved is multiplied by the waste production rate, which is the current dynamically corrected value. The multiplied objects include the unit carbon emission factor of landfill treatment and the unit carbon emission factor of incineration treatment. When landfill and incineration are combined in a known ratio in the construction waste disposal plan, they are multiplied by the corresponding ratio coefficient and then summed.

[0053] All products are summed to generate a stage carbon emission intensity value bound to the current time step. During the construction phase, the summation includes carbon emissions from building materials consumed during construction, energy emissions from construction machinery, and carbon emissions from construction waste disposal. During the operation and maintenance phase, the summation includes energy carbon emissions from HVAC systems, lighting systems, other equipment systems, and carbon emissions from material replacement during operation and maintenance. During the demolition and recycling phase, the summation includes energy carbon emissions from demolition machinery, energy carbon emissions from waste transportation, and carbon emissions from landfill and incineration. After summing all time steps, the values ​​are arranged in time step order to generate a stage carbon emission intensity sequence.

[0054] In practice, after the phased carbon emission intensity sequence is generated, iterative calculation begins. The phased carbon emission intensity sequence is iteratively calculated until the rate of change of carbon emission intensity at each time step meets the convergence condition, outputting the total carbon emission equivalent for the entire building lifecycle. The phased carbon emission intensity sequence generated in the current iteration is then substituted into the full-lifecycle dynamic finite element model. The substitution method is as follows: the phased carbon emission intensity value bound to each time step in the phased carbon emission intensity sequence is used as one of the input conditions for further correction of the material loss factor, equipment energy consumption coefficient, and waste production rate within the corresponding time step. That is, when performing physical field analysis and load condition superposition calculations, the finite element mesh elements corresponding to the high carbon emission intensity region of the previous iteration's time step are given a stricter convergence tolerance to enhance the accuracy of stress and deformation calculations, thereby recalculating the material loss factor, equipment energy consumption coefficient, and waste production rate, and generating the phased carbon emission intensity sequence for the next iteration.

[0055] Calculate the absolute value of the difference between the stage carbon emission intensity values ​​at the same time step in two adjacent iterations, and divide the absolute value of the difference by the stage carbon emission intensity value at the current time step to obtain the rate of change of carbon emission intensity at that time step. Let the th iteration... In the next iteration round The carbon emission intensity value for each time step is , No. In the next iteration round The carbon emission intensity value for each time step is carbon emission intensity change rate Calculate using the following formula:

[0056] in, For the first The rate of change of carbon emission intensity over a time step is dimensionless. For the first In the next iteration round The carbon emission intensity value for each time step, expressed in kilograms of carbon dioxide equivalent. For the first In the next iteration round The carbon emission intensity value for each time step, expressed in kilograms of carbon dioxide equivalent. This indicates the absolute value operation. It applies to all time steps. Calculate one by one ,in This represents the total number of time steps throughout the entire lifecycle.

[0057] The iterative calculation stops when the rate of change of carbon emission intensity for all time steps is less than a preset convergence threshold. The preset convergence threshold is set according to the accuracy requirements of building carbon emission accounting and is set to 0.01. If the rate of change of carbon emission intensity for at least one time step is greater than or equal to 0.01, the next iteration continues. In practice, to avoid infinite iteration, the maximum number of iterations is set to 50. When the number of iterations reaches 50 and the convergence condition is still not met, the stage carbon emission intensity sequence generated in this iteration is output and marked with a non-convergence message. After the iteration stops when the convergence condition is met, all intensity values ​​in the stage carbon emission intensity sequence generated in the last iteration are summed, and the total carbon emission equivalent is output. The unit of the total carbon emission equivalent is kilograms of carbon dioxide equivalent. The summation result is the total carbon emission equivalent for the entire life cycle of the building.

[0058] See Figure 8 The figure illustrates the trend of stage carbon emission intensity with time steps in Example 4 of the building life cycle carbon emission calculation method based on finite element analysis. The horizontal axis represents the time step, covering the construction, operation and maintenance, and demolition and recycling stages within the building life cycle; the vertical axis represents the stage carbon emission intensity, in kilograms of carbon dioxide equivalent per time step (kgCO2 / time step).

[0059] The curve "Carbon Emissions from Building Materials" is marked with a solid line and circles, showing that the carbon emission intensity rapidly decreases from approximately 52 kg CO2 / time step to zero during the initial construction phase (time step 0 to 20). This indicates that carbon emissions from building materials are concentrated and released rapidly during the construction phase, and almost no carbon emissions related to building materials are emitted after construction is completed. The curve "Carbon Emissions from Construction Machinery Energy" is marked with dashed lines and squares, showing significant fluctuations during the construction phase (time step 0 to 20), with a peak value close to 33 kg CO2 / time step. This reflects the fluctuations in carbon emissions from construction machinery energy consumption with changes in the intensity of construction activities, and the carbon emissions tend to be zero after construction is completed. The curve "Carbon Emissions from HVAC Systems Energy" is marked with dotted lines and triangles, starting after time step 20, reflecting the characteristics of the operation and maintenance phase. Carbon emissions fluctuate periodically, with a peak value of approximately 31 kg CO2 / time step. This periodic fluctuation corresponds to changes in energy consumption caused by monthly or seasonal temperature variations.

[0060] The curve for "Carbon Emissions from Lighting and Other Equipment" is represented by a dashed line with an inverted triangle. It shows continuous carbon emissions during the operation, maintenance, dismantling, and recycling phases, with fluctuations concentrated between 5 and 15 kg CO2 per time step, indicating relatively stable carbon emissions from this type of equipment. The curve for "Carbon Emissions from Dismantling and Waste Disposal" is represented by a dashed line with a diamond symbol. It rises significantly during the dismantling and recycling phase (time steps 70 to 100), peaking at approximately 44 kg CO2 per time step, reflecting a substantial increase in carbon emission intensity during dismantling machinery energy consumption and waste disposal. It then gradually decreases to near zero, indicating that dismantling and waste disposal work is gradually completed.

[0061] Overall, the figure accurately reflects the characteristics of the stage carbon emission intensity sequence and time step binding in Example 4. It clearly demonstrates the concentrated release of carbon emissions from building materials and mechanical energy during the construction phase, the cyclical fluctuations of carbon emissions from the energy system during the operation and maintenance phase, and the significant increase in carbon emissions from waste treatment and mechanical energy during the demolition and recycling phase. The trends of each curve and the key carbon emission peak intervals in the figure are consistent with the calculation process of carbon emission factor library matching and retrieval and stage carbon emission intensity generation described in Example 4 of the patent. This reflects the technical effect of accurately generating the carbon emission intensity sequence of each stage of the entire life cycle through the carbon emission factor library after dynamically correcting material loss factors, equipment energy consumption coefficients, and waste production rates.

[0062] Example 5:

[0063] In specific implementation, please refer to Figure 5 The iterative calculation of carbon emission intensity sequences also includes a step of adaptive mesh refinement for the dynamic finite element model throughout the entire life cycle. The physical field gradient difference between adjacent finite element mesh elements in the current iteration is obtained. This physical field gradient difference includes stress gradient difference, temperature gradient difference, or displacement gradient difference. For the stress gradient difference, after completing the physical field analysis of the construction phase in the current iteration, the stress tensor components at the integration points of each finite element mesh element are extracted. These stress tensor components are then extrapolated to the nodes of the finite element mesh elements through interpolation to obtain the nodal stress values. Two adjacent finite element mesh elements share a common surface. The stress values ​​of all nodes on the common surface are mapped to the nodal stress values ​​of their respective elements during the extrapolation process between the two finite element mesh elements. For any node on the common surface, the equivalent stress value extrapolated from the first finite element mesh element is obtained. The equivalent stress value obtained by extrapolating the value of the node in the second finite element mesh element. Calculate the absolute value of the difference between the two equivalent stress values. The maximum absolute value of the difference between all nodes on the common surface is taken as the stress gradient difference between this pair of adjacent finite element mesh elements.

[0064] For the temperature gradient difference, after obtaining the temperature gradient distribution at a certain time step in the current iteration's operation and maintenance phase, the temperature scalar values ​​on all finite element mesh node nodes are extracted. For nodes shared on a common surface between two adjacent finite element mesh elements, any node on the common surface is selected, and its temperature value in the third finite element mesh element is obtained. and the temperature value of the node in the fourth finite element mesh. Calculate the absolute value of the difference between two temperature values. The maximum absolute value of the differences obtained from all nodes on the common surface is taken as the temperature gradient difference between this pair of adjacent finite element mesh elements. For the displacement gradient difference, after obtaining the structural displacement field of the current iteration's construction or demolition / recycling phase, the displacement vectors on all finite element mesh element nodes are extracted. These displacement vectors include X-direction, Y-direction, and Z-direction displacement components. Taking any node on the common surface, the displacement vector magnitude of that node in the fifth finite element mesh element is obtained. and the displacement vector magnitude of the node in the sixth finite element mesh. The magnitude of the displacement vector is obtained by taking the square root of the sum of the squares of the three displacement components. The absolute value of the difference between the magnitudes of the two displacement vectors is then calculated. The maximum absolute value of the difference between all nodes on the common surface is taken as the displacement gradient difference between this pair of adjacent finite element mesh elements.

[0065] Determine whether the gradient difference of the physical field exceeds a preset gradient threshold. The preset gradient threshold is set according to the type of physical field, such as the stress gradient threshold. The value is taken as one-fifteenth of the material's yield stress value, which is the volume-weighted average of the yield stress values ​​assigned to each finite element mesh element in the full-life-cycle dynamic finite element model; temperature gradient threshold. The value is 5 degrees Celsius; displacement gradient threshold The value is taken as one percent of the characteristic size of the finite element mesh element, which is the volume-weighted average of the diameters of the circumscribed spheres of all finite element mesh elements in the dynamic finite element model throughout its entire lifecycle. If the stress gradient difference between a pair of adjacent finite element mesh elements exceeds... Or the temperature gradient difference exceeds Or the displacement gradient difference exceeds If the difference in the physical field gradient exceeds the preset gradient threshold, then it is determined that the difference in the physical field gradient exceeds the preset gradient threshold.

[0066] When the gradient difference of the physical field exceeds a preset gradient threshold, the corresponding adjacent finite element mesh elements are tetrahedralized for refinement. For adjacent finite element mesh element pairs containing hexahedral elements, the hexahedral elements are decomposed into six tetrahedral elements. The decomposition method is to select four non-coplanar vertices of the hexahedron to form the first tetrahedron, the remaining four vertices to form the second tetrahedron, and then further subdivide the remaining volume inside the hexahedron into four tetrahedral elements. For adjacent finite element mesh element pairs that are already tetrahedral elements, the midpoints of each edge of the tetrahedral element are used as new nodes, and a single tetrahedral element is subdivided into eight smaller tetrahedral elements. During the refinement process, material property information, stress state, and temperature values ​​are obtained by interpolation of the original element shape function at the new nodes, maintaining the continuity of the field function. The refined finite element mesh elements are then recombined, replacing the storage location of the original adjacent finite element mesh elements in the overall mesh data structure, and the mapping relationship between node numbers and element numbers is updated. During the recombination process, the node set at the boundary between the finite element mesh element adjacent to the encrypted element but not encrypted itself changes from a single node to multiple newly added nodes. The coordination of the displacement fields between these adjacent finite element mesh elements is ensured by establishing nodal displacement coupling constraint equations, forming an updated full-lifecycle dynamic finite element model for the next iteration. Each iteration only performs adaptive mesh refinement once on local regions where the physical field gradient difference exceeds the gradient threshold in the current iteration.

[0067] See Figure 9 This figure illustrates the distribution of stress gradient differences between adjacent finite element mesh elements in the current iteration during the iterative calculation of the dynamic finite element model throughout the entire life cycle in Example 5. The horizontal axis represents the numbers of adjacent finite element mesh pairs, ranging from 0 to 1000, and the vertical axis represents the stress gradient difference between the corresponding element pairs, in megapascals (MPa). Solid circles represent the distribution of stress gradient differences between all adjacent finite element mesh elements, scattered between 0 and approximately 20 MPa. Crosses mark finite element pairs whose stress gradient differences exceed a preset stress gradient threshold, which is drawn as a dashed line at approximately 20 MPa.

[0068] The stress gradient threshold, indicated by the dashed line in the figure, is one-fifteenth of the material's yield stress. It is calculated by weighted averaging of the material's yield stress across all finite element mesh elements in the full-life-cycle dynamic finite element model. The stress gradient difference between the vast majority of adjacent element pairs is below this threshold, clustering between 5 and 15 MPa, exhibiting a relatively stable gradient distribution. However, several element pairs exceed the threshold, marked with an "X." In extreme cases, the stress gradient difference can reach over 70 MPa, indicating drastic changes in local stress distribution in this region, potentially representing a structural interface or a region of abrupt material property change.

[0069] This figure illustrates the key basis for adaptive mesh refinement of the dynamic finite element model throughout the entire life cycle in Example 5. For element pairs with stress gradient differences exceeding a threshold, the model will perform tetrahedral mesh refinement on their adjacent mesh elements, improving the mesh fineness in that region and ensuring the numerical accuracy and computational stability of the physical field analysis. Through this method, combined with the spatial distribution characteristics of stress gradients, the model can dynamically adjust the finite element mesh structure, achieving a balance between local refinement and overall computational efficiency, and meeting the high requirements for structural mechanical response accuracy in the calculation of building carbon emissions throughout the entire life cycle.

[0070] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application.

Claims

1. A method for calculating carbon emissions throughout the entire life cycle of a building based on finite element analysis, characterized in that, The method includes: Acquire building geometry information, material property information, construction technology information, and equipment operation and maintenance information throughout the entire life cycle of the building, and establish a dynamic finite element model of the entire life cycle that maps to the building structural parameters; Based on the aforementioned full life cycle dynamic finite element model, the time steps for the construction, operation and maintenance, and demolition and recycling stages are divided, and the physical field analysis and load case superposition calculations corresponding to each stage are performed. The material loss factor, equipment energy consumption coefficient, and waste output rate in the full life cycle dynamic finite element model are dynamically corrected by superimposing the physical field analysis and load conditions. The corrected material loss factor, equipment energy consumption coefficient and waste output rate are input into the preset carbon emission factor library for matching and retrieval, generating a phase carbon emission intensity sequence bound to the time step. The carbon emission intensity sequence of the aforementioned stage is iteratively calculated until the rate of change of carbon emission intensity at each time step meets the convergence condition, and the total carbon emission equivalent of the building's entire life cycle is output.

2. The method for calculating building life-cycle carbon emissions based on finite element analysis according to claim 1, characterized in that, The establishment of a full-life-cycle dynamic finite element model mapped to building structural parameters includes the following steps: The building geometry information is discretized into finite element mesh elements, and the material property information is independently assigned to each finite element mesh element. Establish boundary condition mapping relationships between the construction process information and the equipment operation and maintenance information on the nodes of the finite element mesh; Based on the boundary condition mapping relationship, a stiffness matrix and a mass matrix are constructed for calculating the stress field, temperature field, and displacement field of the structure.

3. The method for calculating building life-cycle carbon emissions based on finite element analysis according to claim 2, characterized in that, The finite element mesh is discretized using hexahedral or tetrahedral elements, and the mesh is locally refined at interfaces where material properties change abruptly.

4. The method for calculating building life-cycle carbon emissions based on finite element analysis according to claim 2, characterized in that, The time steps for dividing the construction, operation and maintenance, and demolition and recycling phases, and the superposition calculation of the physical field analysis and load conditions corresponding to each phase, include the following steps: During the construction phase, concrete pouring load, steel structure hoisting load, and temporary support removal load are sequentially applied to each finite element mesh element, and the structural stress and deformation response corresponding to each construction step are calculated. During the operation and maintenance phase, wind load, temperature load, and equipment vibration load are applied simultaneously to each finite element mesh element. The steady-state and transient heat conduction equations are solved to obtain the temperature gradient distribution at each time step during the operation and maintenance phase. During the demolition and recycling phase, directional demolition loads and crushing mechanical impact loads are applied to each finite element mesh element in a time sequence to simulate the progressive degradation process of the structural stiffness matrix.

5. The method for calculating building life-cycle carbon emissions based on finite element analysis according to claim 4, characterized in that, The time steps of the construction phase are divided according to the thickness of the concrete pouring layer or the steel structure hoisting segment, while the time steps of the operation and maintenance phase are divided according to the month or season.

6. The method for calculating building life-cycle carbon emissions based on finite element analysis according to claim 4, characterized in that, The material loss factor in the full-life-cycle dynamic finite element model is dynamically corrected based on the superposition calculation results of the physical field analysis and the load conditions, including the following steps: From the structural stress and deformation response during the construction phase, extract the set of finite element mesh elements that exceed the material yield stress, and calculate the volume of this set; The number of finite element mesh elements that undergo inelastic deformation is extracted from the progressive degradation of the structural stiffness matrix during the demolition and recycling phase. The volume of the finite element mesh set exceeding the material yield stress and the number of finite element mesh elements undergoing inelastic deformation are divided by the total building volume to obtain the construction loss coefficient and the demolition loss coefficient, and the construction loss coefficient and the demolition loss coefficient are used as correction values ​​for the material loss factor.

7. The method for calculating building life-cycle carbon emissions based on finite element analysis according to claim 4, characterized in that, The energy consumption coefficient of the equipment in the dynamic finite element model throughout the entire life cycle is dynamically corrected based on the superposition calculation results of the physical field analysis and the load conditions, including the following steps: From the temperature gradient distribution during the operation and maintenance phase, extract the temperature difference value between the inner and outer surfaces of the building envelope at each time step; Using the temperature difference value as an input parameter, the preset HVAC equipment energy consumption simulation sub-model is called to calculate the theoretical energy consumption value at this time step. The theoretical energy consumption value is compared with the preset benchmark energy consumption value, the ratio factor between the two is calculated, and the ratio factor is used as the dynamic correction amount of the equipment energy consumption coefficient.

8. The method for calculating building life-cycle carbon emissions based on finite element analysis according to claim 7, characterized in that, The energy consumption simulation sub-model of the HVAC equipment dynamically adjusts the start-stop frequency and power setpoint of the HVAC equipment within each time step according to the temperature gradient distribution at each time step of the operation and maintenance phase.

9. The method for calculating building life-cycle carbon emissions based on finite element analysis according to claim 4, characterized in that, The waste production rate in the full-life-cycle dynamic finite element model is dynamically corrected based on the superposition calculation results of the physical field analysis and load conditions, including the following steps: From the finite element mesh cell breakage response under the directional demolition load and the mechanical impact load of the breaking machinery during the demolition and recycling phase, identify mesh cell groups with a size smaller than the preset breakage threshold. The total mass of the grid cell group whose size is smaller than the preset crushing threshold is counted, and this total mass is taken as the mass of fine-particle waste. The correction factor for the waste production rate is obtained by dividing the mass of the fine-particle waste by the total mass of all solid waste generated during the dismantling and recycling phase.

10. The method for calculating building life-cycle carbon emissions based on finite element analysis according to claim 1, characterized in that, The step of inputting the corrected material loss factor, equipment energy consumption coefficient, and waste output rate into a preset carbon emission factor library for matching and retrieval, and generating a phased carbon emission intensity sequence bound to a time step, includes the following steps: Using the material loss factor as an index, the unit carbon emission factor of various building materials such as cement, steel, and sand and gravel is retrieved from the carbon emission factor database; Using the energy consumption coefficient and waste output rate of the equipment as a joint index, the unit carbon emission factor of energy medium and the unit carbon emission factor of various waste treatment methods such as landfill and incineration are retrieved in the carbon emission factor library. The energy medium includes diesel, electricity and gasoline. The unit carbon emission factor of various building materials is multiplied by the preset usage of the corresponding materials, the unit carbon emission factor of various energy media is multiplied by the preset energy consumption, the unit carbon emission factor of various waste treatment methods is multiplied by the waste production rate, and all products are accumulated to generate a stage carbon emission intensity value bound to the current time step. Finally, the stage carbon emission intensity sequence is generated by arranging them in order of time step.

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