A wind-induced fatigue life evaluation method and system for an external thermal insulation system of a high-rise building

Abstract

This invention discloses a method and system for assessing the wind-induced fatigue life of external insulation systems for high-rise buildings, relating to the fields of safety assessment and wind-resistant design technology for building external wall insulation systems. The method includes the following steps: using large eddy simulation (LES) to calculate and assess unsteady wind pressure time history data of the outer surface of a high-rise building under different working conditions and preset atmospheric boundary layer inflow conditions; extracting variable-amplitude stress cycles caused by wind loads at each surface measuring point using rainflow counting, and correcting the stress amplitude by eliminating the influence of average stress on fatigue life; combining the stress-life curve, quantitatively calculating the cumulative damage amount of each surface region of the external insulation system using linear cumulative damage theory, and then calculating the theoretical fatigue failure years of each surface region of the external insulation system by introducing a damage equivalent load. This invention couples LES transient wind pressure field data with material fatigue experimental parameters to achieve efficient assessment of the wind-induced fatigue life of external insulation systems.

Description

Technical Field

[0001] This invention relates to the field of safety assessment and wind-resistant design technology for building exterior wall insulation systems, and particularly to a method and system for assessing the wind-induced fatigue life of exterior insulation systems for high-rise buildings. Background Technology

[0002] Under long-term wind loads, the detachment of external insulation systems in high-rise buildings is a frequent occurrence, seriously threatening urban public safety. Currently, while the RANS method can provide average wind pressure distribution, it struggles to capture the unsteady pulsating characteristics of transient flow structures such as shear separation layers and vortex shedding on building surfaces, making it impossible to accurately characterize the amplitude and frequency of cyclic loads borne by the external insulation system. In terms of fatigue assessment, due to the lack of damage analysis models directly related to transient wind pressure time histories, engineering practice typically relies solely on local extreme wind pressures for structural design, neglecting the material interface fatigue degradation problem under cyclic loading.

[0003] In addition, the interference effects of twin and multi-story buildings, which are common in urban environments, can significantly reconstruct the wind pressure field distribution on the surface of the main building, change the location and area of ​​local high suction areas, and thus induce severe fatigue damage concentration in areas that have not been adequately considered in conventional design. Summary of the Invention

[0004] To address the shortcomings of existing technologies, the purpose of this invention is to provide a method and system for assessing the wind-induced fatigue life of external insulation systems for high-rise buildings. This method couples transient wind pressure field data from Large Eddy Simulation (LES) with material fatigue experimental parameters to achieve efficient assessment of the wind-induced fatigue life of external insulation systems, providing a scientific basis for differentiated wind-resistant design and long-term safe operation and maintenance of external insulation systems for high-rise buildings.

[0005] To achieve the above objectives, the present invention is implemented through the following technical solution: The first aspect of this invention provides a method for assessing the wind-induced fatigue life of an external thermal insulation system for high-rise buildings, comprising the following steps: Obtain the geometric parameters of the high-rise building to be evaluated and the layout information of the surrounding buildings, and establish a computational fluid dynamics numerical model; use the large eddy simulation method to calculate and evaluate the unsteady wind pressure time history data of the outer surface of the high-rise building under the preset atmospheric boundary layer inflow conditions under different working conditions. Based on unsteady wind pressure time history data, the variable amplitude stress cycle caused by wind load at each surface measuring point is extracted using the rainflow counting method. The stress amplitude and the corresponding number of cycles are statistically analyzed, and the stress amplitude is corrected by eliminating the influence of average stress on fatigue life. Based on the modified stress amplitude and cycle number combined with the stress-life curve, the cumulative damage of each surface area of ​​the external insulation system is quantitatively calculated using the linear cumulative damage theory. By introducing the damage equivalent load, the theoretical fatigue failure years of each surface area of ​​the external insulation system are then calculated.

[0006] Furthermore, the geometric parameters of the high-rise building to be evaluated include the depth-to-width ratio and the height-to-width ratio, and the surrounding building layout information includes the relative position parameters of the interfering buildings in at least one of the following dual-building interference conditions: series layout, parallel layout, upstream staggered layout, or downstream layout.

[0007] Furthermore, the specific steps for obtaining unsteady wind pressure time history data are as follows: Based on the depth-to-width ratio, height-to-width ratio, and relative position to adjacent interfering buildings of the high-rise building to be evaluated, a three-dimensional computational fluid dynamics numerical model including the main building and the interfering buildings is established. The inflow boundary adopts the exponential law average wind speed profile and the corresponding turbulence intensity profile, the outlet boundary is set as a pressure outlet, and the building surface and ground adopt the no-slip wall condition. The spatially filtered Navier-Stokes equations were solved using the large eddy simulation method, and the subgrid-scale stresses were closed using a wall-adapted local eddy viscosity model. Multiple pressure measurement points are pre-set on the outer surface of the building, and the instantaneous wind pressure time history data of each measurement point during the entire simulation period are extracted and stored.

[0008] Furthermore, the Goodman mean stress correction criterion is introduced to convert asymmetric cyclic stress into symmetric cyclic stress amplitude, thereby eliminating the influence of mean stress on fatigue life.

[0009] Furthermore, by conducting static tensile tests and cyclic fatigue tests on the bonding interface between the insulation board and polymer mortar used in the external insulation system, the ultimate tensile bearing capacity of the interface failure and the number of fatigue failure cycles under different stress levels were obtained, and the stress-life curve and fatigue constant of the bonding interface were fitted.

[0010] Furthermore, the specific steps for calculating the theoretical fatigue failure years of each surface region of the external insulation system by introducing damage equivalent loads are as follows: The damage equivalent load is defined, and the wind pressure time history of the short-time simulation is converted into the number of annual cycles by combining the time conversion factor. Using the power function relationship of the stress-life curve, the theoretical fatigue failure years of each surface area of ​​the external insulation system are finally calculated.

[0011] A second aspect of the present invention provides a wind-induced fatigue life assessment system for external thermal insulation systems of high-rise buildings, comprising: The wind pressure time history acquisition module is used to acquire the geometric parameters of the high-rise building to be evaluated and the layout information of the surrounding buildings, and to establish a computational fluid dynamics numerical model. The large eddy simulation method is used to calculate and evaluate the unsteady wind pressure time history data of the outer surface of the high-rise building under the preset atmospheric boundary layer inflow conditions under different working conditions. The cycle counting and correction module is used to extract the variable amplitude stress cycle caused by wind load at each surface measuring point based on unsteady wind pressure time history data and rain flow counting method, count each stress amplitude and the corresponding cycle number, and correct the stress amplitude by eliminating the influence of average stress on fatigue life. The damage and life calculation module is used to quantitatively calculate the cumulative damage of each surface area of ​​the external insulation system based on the corrected stress amplitude and cycle number combined with the stress-life curve, and then calculate the theoretical fatigue failure years of each surface area of ​​the external insulation system.

[0012] A third aspect of the present invention provides a computer-readable storage medium storing a computer program adapted to be loaded by a processor and to execute the steps in the method for assessing the wind-induced fatigue life of an external thermal insulation system for high-rise buildings as described in the first aspect of the present invention.

[0013] A fourth aspect of the present invention provides a computer device comprising: A processor, adapted to execute computer programs; A computer-readable storage medium storing a computer program, which, when executed by the processor, implements the wind-induced fatigue life assessment method for external thermal insulation systems of high-rise buildings as described in the first aspect of the present invention.

[0014] A fifth aspect of the present invention provides a computer program product or computer program comprising computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform the steps in the method for assessing the wind-induced fatigue life of an external thermal insulation system for high-rise buildings as described in the first aspect of the present invention.

[0015] The above one or more technical solutions have the following beneficial effects: This invention discloses a method and system for assessing the wind-induced fatigue life of external insulation systems for high-rise buildings. It provides a systematic assessment method that can comprehensively consider building geometric parameters, interference effects of multiple buildings, unsteady wind pressure time history characteristics, and material fatigue performance. This method ensures that the wind-resistant design of external insulation systems remains at the level of static and deterministic strength verification, making it difficult to meet the needs of full life cycle safety management.

[0016] This invention couples transient wind pressure field data from Large Eddy Simulation (LES) with fatigue SN curves of the bonding interface of thermal insulation materials. By utilizing the rainflow counting method and Palmgren-Miner linear cumulative damage theory, a complete evaluation framework is constructed from "unsteady wind load - interface cumulative damage - theoretical fatigue failure years". The aim is to provide quantitative basis for the wind resistance durability design and operation and maintenance of external thermal insulation systems in complex urban wind environments.

[0017] Advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 This is a flowchart of the wind-induced fatigue life assessment method for the external thermal insulation system of high-rise buildings in Embodiment 1 of the present invention; Figure 2 This is a diagram showing the arrangement of measuring points in Embodiment 1 of the present invention; Figure 3 This is a flowchart of the load spectrum analysis in Embodiment 1 of the present invention; Figure 4 This is a cloud map showing the distribution of crosswind damage at different aspect ratios in Embodiment 1 of the present invention; Figure 5 This is a cloud map showing the distribution of crosswind damage years with different aspect ratios in Embodiment 1 of the present invention; Figure 6 This is a cloud map showing the distribution of damage years on the windward side at different interference locations in Embodiment 1 of the present invention; Figure 7 This is a cloud map showing the crosswind damage distribution at different interference locations in Embodiment 1 of the present invention; Figure 8 This is a cloud map showing the distribution of damage years on the leeward side at different interference locations in Embodiment 1 of the present invention. Detailed Implementation

[0020] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0021] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof. The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0022] Example 1: Embodiment 1 of this invention provides a method for assessing the wind-induced fatigue life of an external thermal insulation system for high-rise buildings. The method and system employ large eddy simulation to obtain unsteady wind pressure time history data of the building's external surface under preset wind field conditions. Through static tensile and cyclic load fatigue experiments at the interface between the insulation board and polymer mortar, the stress-life (SN) curve of the interface is fitted. Variable amplitude stress cycles are extracted using the rainflow counting method, and the asymmetric cycle is equivalently converted to symmetric cycle stress amplitude using the Goodman mean stress correction criterion. Based on the corrected stress amplitude and the number of statistical cycles, combined with the SN curve, the cumulative damage amount of each surface region is calculated using the Palmgren-Miner linear cumulative damage theory. Finally, the damage equivalent load is defined, and combined with a time conversion factor, the theoretical fatigue failure years of each surface region of the external thermal insulation system are calculated. This invention couples transient wind pressure field data from large eddy simulation with material interface fatigue test parameters to construct a complete evaluation framework from "unsteady wind load - interface cumulative damage - service life prediction". It can effectively consider the impact of aspect ratio, height-to-width ratio and twin-building interference effect on the wind-induced fatigue life of external insulation system, and provides a quantitative basis for differentiated wind-resistant design and long-term safe operation and maintenance of external insulation system in complex urban wind environment.

[0023] like Figure 1 As shown, the specific steps include: S1: Obtain the geometric parameters of the high-rise building to be evaluated and the layout information of surrounding buildings, and establish a computational fluid dynamics numerical model; use the large eddy simulation method to calculate and evaluate the unsteady wind pressure time history data of the outer surface of the high-rise building under the preset atmospheric boundary layer inflow conditions under different working conditions.

[0024] S1.1: Obtain the geometric parameters of the high-rise building to be evaluated and the layout information of the surrounding buildings.

[0025] In one specific implementation, the geometric parameters of the high-rise building to be evaluated include the depth-to-width ratio and the height-to-width ratio, and the surrounding building layout information includes the relative position parameters of the interfering buildings in at least one of the following dual-building interference conditions: series layout, parallel layout, upstream staggered layout, or downstream layout.

[0026] In this embodiment, a three-dimensional computational fluid dynamics (CFD) numerical model is established based on the geometric parameters of the high-rise building to be evaluated, including its depth-to-width ratio (D / B), height-to-width ratio (H / B), and relative positional relationship with adjacent interfering buildings. For isolated building cases, the selectable range of the depth-to-width ratio covers 0.33 to 9.0, and the selectable range of the height-to-width ratio covers 2 to 8. For two-building interference cases, the position of the interfering building relative to the main building (fixed at the origin) can cover four typical interference modes: series layout (e.g., (-4,0), (-3,0), (-1.5,0)), parallel layout (e.g., (0,3), (0,2), (0,1.5)), upstream staggered layout (e.g., (-5,3), (-3,3), (-2.5,2.5)), and downstream layout (e.g., (2,2), (1,2), (1.5,0)).

[0027] S1.2: Establish a computational fluid dynamics numerical model based on the obtained geometric parameters and surrounding building layout information.

[0028] In one specific implementation, a three-dimensional computational fluid dynamics numerical model is established based on the depth-to-width ratio, height-to-width ratio, and relative position of the high-rise building to be evaluated and its neighboring interfering buildings. The model includes the main building and the interfering buildings. The inflow boundary adopts an exponential law mean wind speed profile and a corresponding turbulence intensity profile that conform to the urban topography. The outlet boundary is set as a pressure outlet. The top and sides of the computational domain adopt symmetrical boundary conditions, and the building surface and ground adopt no-slip wall conditions.

[0029] In this embodiment, the dimensions of the computational domain are set as follows: a span of 2.5H + 5H in the downwind direction (x-axis), a span of 2.5H in the vertical direction (y-axis), and a span of 5H in the crosswind direction (z-axis), where H is the building height, ensuring a blockage rate of less than 3%. The inflow boundary is set according to the exponential wind speed profile model specified in existing standards. , , , , .

[0030] in, V At the target altitude y wind speed, For reference height Reference wind speed at the location I 0 is the reference height Y Turbulence intensity at 0 The power-law exponent corresponding to the surface roughness category. C μ This is an empirical constant, taken as 0.09. ε For turbulent dissipation rate, l The turbulence length scale. Inflow turbulence intensity. Turbulent kinetic energy With specific dissipation rate The distribution along the height is also defined by the corresponding profile function. The outlet boundary is set as a pressure outlet, the top surface and two side boundaries of the computational domain are set as symmetrical boundary conditions, and the building surface and ground are set as no-slip wall conditions.

[0031] S1.3: Based on the numerical model of fluid dynamics, the large eddy simulation method is used to calculate and evaluate the unsteady wind pressure time history data of the outer surface of high-rise buildings under preset atmospheric boundary layer inflow conditions under different working conditions.

[0032] S1.3.1: The spatially filtered Navier-Stokes equations are solved using the large eddy simulation method, and the subgrid-scale stresses are closed using the wall-adapted local eddy viscosity (WALE) model.

[0033] In one specific implementation, the numerical solution in this embodiment employs the Large Eddy Simulation (LES) method. The energetic large-scale vortex structure is directly analyzed using the spatially filtered Navier-Stokes governing equations. Subgrid-scale stresses are closed using a Wall Adapted Local Eddy Viscosity (WALE) model to capture the transient characteristics of near-wall separation flow and vortex shedding, accurately capturing transient flow phenomena such as near-wall separation shear layers, vortex shedding, and reattachment. The time step is 0.002 s, and the total simulation physical duration is 10 s.

[0034] S1.3.2: Pre-set multiple pressure measurement points on the outer surface of the building, extract and store the instantaneous wind pressure time history data of each measurement point throughout the entire simulation period.

[0035] In one specific implementation, a total of 420 pressure measuring points are evenly distributed on the windward, leeward, and crosswind sides of the building, such as... Figure 2 As shown, the instantaneous wind pressure coefficient time history of each measuring point is extracted and stored throughout the entire simulation period. Wind pressure coefficient The definition of is: .

[0036] in, p i For the instantaneous pressure at the measuring point, for p i The average value, For reference static pressure, air density, The average wind speed is located at a reference height at the top of the building. Comparison with wind tunnel experimental data from a standard high-rise building model provided by the Commonwealth Advisory Aeronautical Research Council (CAARC) shows that the average wind pressure coefficient distribution obtained in this embodiment matches the experimental results well, with an average drag coefficient deviation of approximately 2.5%, demonstrating the reliability of the numerical method used.

[0037] This invention uses Large Eddy Simulation (LES) technology to obtain high-resolution transient wind pressure time histories of building exterior surfaces. Compared with traditional steady-state calculation methods based on Reynolds averages (RANS), it can more accurately characterize the amplitude and frequency of unsteady flow features such as shear separation and vortex shedding that generate real cyclic loads on the external insulation system, providing a more reliable load input for fatigue analysis.

[0038] The method of this invention is not only applicable to isolated high-rise buildings, but also fully considers the reconstruction effect of typical double-building interference such as series, parallel and upstream staggered connections on fatigue damage distribution. It can effectively meet the engineering needs of fatigue risk assessment of external insulation systems in complex urban building complex environments, and provide precise guidance for differentiated wind-resistant structural design and targeted local anchoring reinforcement.

[0039] S2: Based on unsteady wind pressure time history data, the variable amplitude stress cycle caused by wind load at each surface measuring point is extracted using the rain flow counting method. The stress amplitude and the corresponding number of cycles are statistically analyzed, and the stress amplitude is corrected by eliminating the influence of average stress on fatigue life.

[0040] S2.1: Based on unsteady wind pressure time history data, the variable amplitude stress cycle caused by wind load at each surface measuring point is extracted using the rainflow counting method, and the stress amplitude and corresponding cycle number are statistically analyzed.

[0041] In one specific implementation, the instantaneous wind pressure time history data obtained from large eddy simulation at each measuring point is converted into a normal alternating stress history acting on the bonding interface of the external insulation system. The stress time history is then iteratively extracted using the rainflow counting method, decomposing the random amplitude load history into a series of discrete full-cycle and semi-cycle events, and extracting the stress amplitude of each cycle. mean stress Location coordinates and the corresponding number of cycles The core algorithm logic of the rainflow counting method is as follows: Figure 3 As shown, this includes raw data acquisition and preprocessing, rainflow counting and cyclic extraction, unified binning operation across the entire domain, and damage measurement. The process includes calculation, equivalent transformation and life mapping, data output and summarization. This step transforms the non-stationary wind pressure pulsation signal into statistics that can be directly used in fatigue analysis, and is a key intermediate link connecting aerodynamic loads and material damage.

[0042] S2.2: The stress amplitude is corrected by eliminating the influence of mean stress on fatigue life.

[0043] In one specific implementation, the wind load in this embodiment is an asymmetric cyclic stress. Therefore, by introducing the Goodman mean stress correction criterion, the asymmetric cyclic stress is equivalently transformed into a symmetric cyclic stress amplitude to eliminate the influence of mean stress on fatigue life.

[0044] Specifically, because external insulation systems under wind loads often experience alternating positive and negative asymmetric stress cycles, their average stress... Since the value is usually not zero, directly applying the SN curve under symmetrical cyclic conditions will lead to deviations in fatigue life prediction. This embodiment introduces the Goodman mean stress correction criterion to perform an equivalent transformation on the amplitude of each stress cycle. The specific equivalent transformation process for asymmetric cyclic stress is as follows: For each stress cycle extracted from the wind pressure time history, its stress amplitude is considered. With average stress Using the Goodman mean stress correction criterion: , .

[0045] The asymmetric cycle is equivalent to the stress amplitude of the corresponding symmetric cycle. , r This is a correction factor.

[0046] in. This is the corrected equivalent symmetrical cyclic stress amplitude. The ultimate tensile strength of the interface (here, its equivalent failure stress) is measured by static tensile tests and cyclic fatigue tests. This step corrects for the influence of the non-zero mean stress caused by the alternating positive and negative characteristics of wind loads on the fatigue life of the component, so that subsequent damage accumulation calculations are based on a unified symmetrical cyclic stress benchmark.

[0047] This correction maps the actual asymmetric tension-tension or tension-compression cycles onto the symmetric cycle benchmark, effectively eliminating the nonlinear effect of mean stress on fatigue damage accumulation, making subsequent life calculations based on SN curves more conservative and safer.

[0048] This invention introduces the Goodman mean stress correction criterion, which transforms the asymmetric tensile-compressive cyclic stress caused by wind load into an equivalent symmetric cyclic stress, eliminating the optimistic estimate of fatigue life caused by neglecting mean stress in conventional analysis. At the same time, the SN curves of the insulation board-mortar interface under different adhesion rates are experimentally calibrated, giving the damage calculation a solid foundation of material mechanics parameters.

[0049] S3: Based on the modified stress amplitude and cycle number combined with the stress life curve, the cumulative damage of each surface area of ​​the external insulation system is quantitatively calculated using the linear cumulative damage theory. By introducing the damage equivalent load, the theoretical fatigue failure years of each surface area of ​​the external insulation system are then calculated.

[0050] S3.1: By conducting static tensile tests and cyclic load fatigue tests on the bonding interface between the insulation board and polymer mortar used in the external insulation system, the ultimate tensile bearing capacity of the interface failure and the number of fatigue failure cycles under different stress levels are obtained, and the stress life curve and fatigue constant of the bonding interface are obtained by fitting.

[0051] In one specific implementation, the process of obtaining the interface stress-life (SN) curve in this embodiment is as follows: Insulation boards and polymer bonding mortar, matching the actual engineering requirements, were selected, and tensile specimens were fabricated according to a predetermined bonding area ratio. First, a displacement-controlled static uniaxial tensile failure test was conducted using a universal testing machine to obtain the average ultimate tensile bearing capacity of the specimens. Subsequently, using a fatigue testing machine, under a sinusoidal wave loading at a frequency of 10 Hz, the load-bearing capacity was tested. Based on this, tensile fatigue tests were conducted at at least four different stress levels (e.g., 0.2F, 0.4F, 0.6F, 0.8F), with a constant minimum load set at 10 N. The number of fatigue failure cycles until interface delamination was recorded at each stress level. ; Regarding the obtained stress amplitude With fatigue failure cycle number Least squares regression was performed in a double logarithmic coordinate system to obtain the SN curve that conforms to the Basquin power function law, thus determining the fatigue index of the material. With material constants .

[0052] In this embodiment, high-density molded polystyrene (EPS) insulation board with a density of 18 kg / m³ was selected as the insulation material, and autoclaved aerated concrete (A5.0B07) blocks were used as the base layer. Polymer bonding mortar was used as the adhesive. The specimens were fabricated according to the relevant requirements of current industry standards, using a strip bonding process with a 60% adhesion rate to form a standard bonding interface between the 100 mm × 100 mm insulation board and the blocks. After bonding, the specimens were cured at room temperature for 14 days. Subsequently, 100 mm × 100 mm special tensile clamps were attached to the upper and lower surfaces respectively, and the specimens were placed in a 70 ℃ constant temperature chamber for 8 hours to cure the structural adhesive, ultimately forming a complete tensile specimen that can be clamped by a testing machine.

[0053] Static uniaxial tensile failure tests were conducted on an INSTRON 68TM-30 universal testing machine with a loading rate set at 5 mm / min. The maximum load until interfacial delamination failure was recorded. The arithmetic mean of the test results for three sets of parallel specimens (60% strip bond condition) was taken to obtain the average ultimate tensile strength. .

[0054] Cyclic fatigue tests were conducted on an INSTRON 8801 electro-hydraulic servo fatigue testing machine. A 10 Hz sinusoidal continuous loading method was used to study the interfacial fatigue performance under tension-tension fatigue (i.e., tensile stress throughout the cyclic loading process). During the experiment, the minimum load was constantly set at 10 N, and the maximum loads were set at four stress levels: 0.2F, 0.4F, 0.6F, and 0.8F. Each stress level group included three parallel specimens. The system automatically recorded the number of fatigue cycles N until interface delamination for each specimen. The average value of each group of parallel specimens was taken as the final fatigue life at that stress level. The experimental results are summarized in Table 1.

[0055] Table 1. Failure load and fatigue cycles of EPS insulation boards under different bonding methods

[0056] The obtained stress amplitude With fatigue life Linear regression using the least squares method in a double logarithmic coordinate system yields the SN curve equation that conforms to the Basquin power function law: .

[0057] in, The fatigue index. Let be the material fatigue constant. For the 60% strip-bonded condition, the fitted fatigue constant is: , This SN relationship provides crucial material constitutive parameters for the quantitative calculation of fatigue damage under all subsequent working conditions. The final failure mode observed in the experiment was the delamination of the interface between the insulation board and the mortar adhesive, indicating that interfacial bonding failure is the core failure mode of the external insulation system under cyclic loading.

[0058] In one specific implementation, this embodiment uses the corrected stress amplitude and cycle number, combined with the SN curve and Miner's linear cumulative damage theory, to quantitatively calculate the theoretical fatigue failure years of each surface region.

[0059] In this embodiment, to facilitate qualitative identification of the relative fatigue sensitivity of different surfaces or under different working conditions of the same building, the damage quantity is first defined. The indicator, its expression is: .

[0060] In the formula, This represents the range of equivalent stress amplitudes after the i-th level correction. This represents the number of cycles corresponding to this amplitude. This is the fatigue index, already calibrated in the SN curve. This index is independent of the absolute strength value of a specific material and can intuitively reflect the relative fatigue risk of different facade areas in cross-condition comparisons. Damage quantity is used to qualitatively compare the relative fatigue risk of different areas or different design conditions of the same building without depending on specific calendar times.

[0061] S3.3: The theoretical fatigue failure years of each surface area of ​​the external insulation system are calculated by introducing damage equivalent load.

[0062] In one specific implementation, this embodiment defines the damage equivalent load and combines it with a time conversion factor to convert the short-time simulated wind pressure time history into the number of annual cycles. Using the power function relationship of the stress-life curve, the theoretical fatigue failure years of each surface area of ​​the external insulation system are finally calculated.

[0063] To perform quantitative lifetime prediction, the Damage Equivalent Load (DEL) is further defined: .

[0064] in, The damage equivalent load refers to the load applied at a given reference equivalent number of cycles. Below this, a single equivalent stress range can be generated that is equivalent to the total damage caused by all collected fatigue cycles.

[0065] Subsequently, by combining the scaling conversion relationship between simulated duration and real time, the equivalent number of cycles per year is derived, and finally, based on the aforementioned SN curve relationship: .

[0066] Furthermore, the scaling factor of the simulated working condition and its relationship with time conversion are considered. In this embodiment, the scaling factor is set to 400, and the simulation duration is 10 seconds, corresponding to the equivalent fatigue damage accumulation within 10 seconds in reality. To annualize the short-time simulation results, a time conversion factor needs to be introduced. Therefore, the formula for calculating the theoretical fatigue failure age T (in years) is as follows: .

[0067] Wherein, constant 10 is the simulated physical duration (s), 3600 is the conversion factor between hours and seconds, and 365 is the number of days in a year.

[0068] The annual cumulative damage and theoretical fatigue failure life of each region were calculated. .

[0069] Applying the above calculation process to the data from each measuring point yields a spatial distribution cloud map of the damage amount and a distribution cloud map of the theoretical fatigue failure age on the entire building's exterior surface. Comparative analysis of different aspect ratios and dual-building interference conditions shows: For isolated buildings, when the depth-to-width ratio (D / B) is between 0.66 and 2.0, the trailing edge region of the crosswind side exhibits significant fatigue damage concentration characteristics, such as... Figure 4 As shown, under the reference wind speed of 11.4 m / s, the theoretical fatigue failure age of the middle of the trailing edge of the crosswind surface under the conditions of D / B=1.0 and D / B=1.5 can be as low as less than 20 years. Figure 5 As shown, this constitutes the weakest link in the system design.

[0070] For twin-building interference scenarios, a series layout (such as INT6#3, with the interfering building located at (-1.5, 0)) causes the windward side to change from a compressive fatigue state to a tensile fatigue state, reducing the theoretical service life of its side edges and top edge area to less than 20 years. Figure 6 As shown, the central region remains above 100 years; the parallel and upstream staggered layouts significantly amplify the fatigue risk in the middle and rear of the crosswind surface, and the area of ​​high damage is significantly larger than that of the isolated case, such as Figure 7 and Figure 8 As shown.

[0071] This invention integrates a two-level evaluation system of damage amount Im and theoretical fatigue failure life T, which can quickly and qualitatively locate fatigue-sensitive areas under different geometric parameters and dual-building interference conditions, and can also provide quantitative service time predictions for each part under the reference wind speed. It realizes a graded assessment from "regional risk screening" to "point life prediction", and can especially identify fatigue-critical parts such as the middle of the crosswind surface that cannot be found by static extreme wind pressure alone.

[0072] Example 2: Embodiment 2 of the present invention provides a wind-induced fatigue life assessment system for external thermal insulation systems of high-rise buildings, comprising: The wind pressure time history acquisition module is used to acquire the geometric parameters of the high-rise building to be evaluated and the layout information of the surrounding buildings, and to establish a computational fluid dynamics numerical model. The large eddy simulation method is used to calculate and evaluate the unsteady wind pressure time history data of the outer surface of the high-rise building under the preset atmospheric boundary layer inflow conditions under different working conditions. The cycle counting and correction module is used to extract the variable amplitude stress cycle caused by wind load at each surface measuring point based on unsteady wind pressure time history data and rain flow counting method, count each stress amplitude and the corresponding cycle number, and correct the stress amplitude by eliminating the influence of average stress on fatigue life. The damage and life calculation module is used to quantitatively calculate the cumulative damage of each surface area of ​​the external insulation system based on the corrected stress amplitude and cycle number combined with the stress-life curve, and then calculate the theoretical fatigue failure years of each surface area of ​​the external insulation system.

[0073] Example 3: Embodiment 3 of the present invention provides a computer-readable storage medium storing a computer program adapted to be loaded by a processor and executed the steps in the method for assessing the wind-induced fatigue life of an external thermal insulation system for high-rise buildings as described in Embodiment 1 of the present invention.

[0074] Example 4: Embodiment 4 of the present invention provides a computer device, the device comprising: A processor, adapted to execute computer programs; A computer-readable storage medium storing a computer program, which, when executed by the processor, implements the steps in the wind-induced fatigue life assessment method for the external thermal insulation system of a high-rise building as described in Embodiment 1 of the present invention.

[0075] Example 5: Embodiment 5 of the present invention provides a computer program product or computer program, which includes computer instructions stored in a computer-readable storage medium. A processor of a computer device reads the computer instructions from the computer-readable storage medium and executes the computer instructions, causing the computer device to perform the steps in the wind-induced fatigue life assessment method for high-rise building external insulation systems as described in Embodiment 1 of the present invention.

[0076] The steps and methods involved in Examples 2, 3, 4 and 5 above correspond to those in Example 1. For specific implementation methods, please refer to the relevant description section of Example 1.

[0077] Those skilled in the art will recognize that the units and algorithm steps of the various examples described in conjunction with the embodiments disclosed in this application can be implemented in electronic hardware or a combination of computer software and electronic hardware. Whether these functions are implemented in hardware or software depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0078] In the above embodiments, implementation can be achieved, in whole or in part, through software, hardware, firmware, or any combination thereof. When implemented in software, it can be implemented, in whole or in part, as a computer program product. A computer program product includes one or more computer instructions. When the computer program instructions are loaded and executed on a computer, all or part of the flow or function according to the embodiments of this application is generated. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable device. The computer instructions can be stored in or transmitted through a computer-readable storage medium. The computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center via wired or wireless means. The computer-readable storage medium can be any available medium that a computer can access or a data processing device such as a server or data center that integrates one or more available media. The available medium can be a magnetic medium, an optical medium, or a semiconductor medium, etc.

[0079] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations 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. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for assessing the wind-induced fatigue life of an external thermal insulation system for high-rise buildings, characterized in that, Includes the following steps: The geometric parameters of the high-rise building to be evaluated and the layout information of surrounding buildings were obtained, and a computational fluid dynamics numerical model was established. Large eddy simulation (LES) was used to calculate and evaluate the unsteady wind pressure time history data of the outer surface of the high-rise building under different operating conditions and under preset atmospheric boundary layer inflow conditions. Specifically, the steps for obtaining the unsteady wind pressure time history data are as follows: Based on the depth-to-width ratio, height-to-width ratio, and relative position to adjacent interfering buildings of the high-rise building to be evaluated, a three-dimensional computational fluid dynamics numerical model including the main building and interfering buildings was established. The inflow boundary adopted an exponential law average wind speed profile and a corresponding turbulence intensity profile, the outlet boundary was set as a pressure outlet, and the building surface and ground were subjected to no-slip wall conditions. The spatially filtered Navier-Stokes equations were solved using LES, and the subgrid-scale stress was closed using a wall-adapted local eddy viscosity model. Multiple pressure measuring points were preset on the outer surface of the building, and the instantaneous wind pressure time history data of each measuring point over the entire simulation period were extracted and stored. Based on unsteady wind pressure time history data, the variable amplitude stress cycle caused by wind load at each surface measuring point is extracted using the rainflow counting method. The stress amplitude and the corresponding number of cycles are statistically analyzed, and the stress amplitude is corrected by eliminating the influence of average stress on fatigue life. Based on the modified stress amplitude and cycle number combined with the stress-life curve, the cumulative damage of each surface area of ​​the external insulation system is quantitatively calculated using the linear cumulative damage theory. By introducing the damage equivalent load, the theoretical fatigue failure years of each surface area of ​​the external insulation system are then calculated.

2. The method for assessing the wind-induced fatigue life of an external thermal insulation system for high-rise buildings as described in claim 1, characterized in that, The geometric parameters of the high-rise building to be evaluated include the depth-to-width ratio and the height-to-width ratio. The surrounding building layout information includes the relative position parameters of the interfering buildings in at least one of the following dual-building interference conditions: series layout, parallel layout, upstream staggered layout, or downstream layout.

3. The method for assessing the wind-induced fatigue life of an external thermal insulation system for high-rise buildings as described in claim 1, characterized in that, The Goodman mean stress correction criterion is introduced to convert asymmetric cyclic stress into symmetric cyclic stress amplitude, thereby eliminating the influence of mean stress on fatigue life.

4. The method for assessing the wind-induced fatigue life of an external thermal insulation system for high-rise buildings as described in claim 1, characterized in that, By conducting static tensile tests and cyclic fatigue tests on the bonding interface between the insulation board and polymer mortar used in the external insulation system, the ultimate tensile bearing capacity of the interface failure and the number of fatigue failure cycles under different stress levels were obtained. The stress-life curve and fatigue constant of the bonding interface were then fitted.

5. The method for assessing the wind-induced fatigue life of an external thermal insulation system for high-rise buildings as described in claim 1, characterized in that, The specific steps for calculating the theoretical fatigue failure years of each surface region of the external insulation system by introducing an equivalent damage load are as follows: The damage equivalent load is defined, and the wind pressure time history of the short-time simulation is converted into the number of annual cycles by combining the time conversion factor. Using the power function relationship of the stress-life curve, the theoretical fatigue failure years of each surface area of ​​the external insulation system are finally calculated.

6. A wind-induced fatigue life assessment system for external thermal insulation systems of high-rise buildings, characterized in that, include: The wind pressure time history acquisition module is used to acquire the geometric parameters of the high-rise building to be evaluated and the layout information of surrounding buildings, and to establish a computational fluid dynamics numerical model. Large eddy simulation (LES) is used to calculate and evaluate the unsteady wind pressure time history data of the outer surface of the high-rise building under different operating conditions and preset atmospheric boundary layer inflow conditions. Specifically, the steps for acquiring the unsteady wind pressure time history data are as follows: Based on the depth-to-width ratio, height-to-width ratio, and relative position to adjacent interfering buildings of the high-rise building to be evaluated, a three-dimensional computational fluid dynamics numerical model including the main building and interfering buildings is established. The inflow boundary uses an exponential law average wind speed profile and a corresponding turbulence intensity profile, the outlet boundary is set as a pressure outlet, and the building surface and ground are subjected to no-slip wall conditions. The spatially filtered Navier-Stokes equations are solved using LES, and the subgrid-scale stress is closed using a wall-adapted local eddy viscosity model. Multiple pressure measuring points are preset on the outer surface of the building, and the instantaneous wind pressure time history data of each measuring point over the entire simulation period are extracted and stored. The cycle counting and correction module is used to extract the variable amplitude stress cycle caused by wind load at each surface measuring point based on unsteady wind pressure time history data and rain flow counting method, count each stress amplitude and the corresponding cycle number, and correct the stress amplitude by eliminating the influence of average stress on fatigue life. The damage and life calculation module is used to quantitatively calculate the cumulative damage of each surface area of ​​the external insulation system based on the corrected stress amplitude and cycle number combined with the stress-life curve, and then calculate the theoretical fatigue failure years of each surface area of ​​the external insulation system.

7. A computer program product, characterized in that, The computer program product includes a computer program that, when executed by a processor, implements the wind-induced fatigue life assessment method for the external thermal insulation system of high-rise buildings as described in any one of claims 1-5.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program adapted to be loaded by a processor and executed as described in any one of claims 1-5, for the method of assessing the wind-induced fatigue life of an external thermal insulation system for high-rise buildings.

9. A computer device, characterized in that, include: A processor, adapted to execute computer programs; A computer-readable storage medium storing a computer program, which, when executed by the processor, implements the method for assessing the wind-induced fatigue life of an external thermal insulation system for high-rise buildings as described in any one of claims 1-5.

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