Method for evaluating damage of long-lasting shock waves to engineering target in consideration of environment temperature

Abstract

The invention belongs to the field of electric digital data processing, and relates to a method for evaluating damage of long-lasting shock waves to an engineering target by considering environment temperature, which comprises the following steps of: calibrating normal-temperature constitutive model parameters; establishing a normal-temperature long-duration explosion numerical simulation model; calibrating constitutive model parameters at different temperatures; establishing a different-temperature explosion numerical simulation model, and performing explosion process numerical simulation to obtain different-temperature numerical simulation damage data; substituting the simulated damage data into a classical P-I curve expression for fitting, and establishing a P-I curve damage criterion expression at different temperatures; substituting the temperature empirical formula into a P-I curve damage criterion expression at different temperatures to obtain a damage criterion considering the temperature effect; and based on the damage criterion considering the temperature effect, completing the damage assessment work according to the characteristics of the to-be-assessed engineering target and the environment temperature. The method does not need to depend on physical tests, and can efficiently complete engineering target damage assessment under the action of long-lasting explosive shock waves through a numerical simulation technology and algorithm.

Description

Technical Field

[0001] The invention belongs to the technical field of explosion damage electrical digital data processing, and in particular relates to a method for evaluating damage to engineering targets caused by long-lasting shock waves taking into account ambient temperature. Background Art

[0002] In modern military decision-making, scientific and quantitative damage assessment is a key component of victory in war. Currently, one of the pre-battle damage assessment tasks involves determining the type of munitions based on strategic intent. For example, if the strategic intent is to inflict severe damage to an engineering target, the required munitions type and parameters must be determined based on the strategic intent and the physical properties of the target. This provides accurate decision-making for operational commanders, evaluates operational effectiveness, and provides a core engineering reference for optimizing subsequent strike strategies.

[0003] With the widespread use of high-yield high-energy explosives and the increasing militarization of underground space, the damage caused by long-lasting blast waves (typically lasting >30ms, potentially reaching seconds) to building structures urgently requires research. When a long-lasting blast wave acts on a building structure, it induces a significant cumulative effect on the overall dynamic response. This continuous load-driven structural system undergoes a complex, multi-stage nonlinear failure process: from the initiation and evolution of material damage to the instability of connection nodes, ultimately leading to the overall collapse of the structure. The failure mechanism is highly complex and difficult to predict. Existing technologies, most of which focus on assessing the localized destructive effects of short-lasting (millisecond-level) contact explosions, are not applicable to the damage assessment of long-lasting blast shock waves.

[0004] Furthermore, battlefield environments (particularly polar, alpine, and mountainous regions) experience significant temperature fluctuations. The mechanical properties of building materials, particularly reinforced concrete (RC), are highly sensitive to ambient temperature. Temperature fluctuations can significantly alter the constitutive relationships, dynamic strength, stiffness, and energy dissipation mechanisms of materials such as concrete and steel. Low temperatures exacerbate concrete brittleness and degrade the synergistic performance of steel-concrete interaction, significantly impacting the dynamic response characteristics, damage development paths, and ultimate failure modes of RC structures. Existing damage assessment methods are generally based on ambient temperature conditions, seriously neglecting the crucial role of ambient temperature as a key variable. This leads to significant deviations in assessment results in special environments such as alpine and fluctuating temperatures, compromising the accuracy and reliability of decision-making.

[0005] Traditional explosion testing methods struggle to directly conduct long-duration, temperature-stable explosions. For example, while high-yield field tests can produce long-lasting explosive shock waves, they require extremely high explosive yields (tens to hundreds of kilograms), resulting in stringent site safety requirements, high costs, and significant destructive potential. Furthermore, precise control and maintenance of target ambient temperatures are difficult in the field. Explosive shock tube technology is commonly used in laboratories, producing long-lasting explosive shock waves with a small amount of explosives. However, to meet the requirements of testing over a wide temperature range (especially low-temperature and high-altitude environments), dedicated large-scale constant-temperature and variable-temperature shock tube facilities are required. These facilities are extremely expensive to design, build, and maintain, and present significant engineering challenges. Furthermore, integrating large-scale, high-performance temperature control systems into existing shock tube systems presents uncontrollable safety risks.

[0006] In summary, accurately quantifying the damage to engineering targets subjected to sustained blast wave loading in realistic battlefield environments with varying temperatures (especially those characterized by high and low temperatures) presents two significant challenges: First, high-fidelity physical simulations of sustained blast waves are limited; second, existing testing techniques present significant difficulties in obtaining reliable data on the mechanisms by which the coupling of ambient temperature and sustained blast waves affects material dynamic properties and structural responses. This necessitates the development of a new quantitative damage assessment method for engineering targets that effectively integrates the effects of ambient temperature and the coupled effects of sustained blast waves, independent of physical testing under extreme conditions. Summary of the Invention

[0007] The purpose of the present invention is to solve the above-mentioned shortcomings in the prior art and to propose a method for assessing the damage of engineering targets caused by long-lasting shock waves taking into account the ambient temperature, so as to achieve rapid and efficient damage assessment.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions: The damage assessment method of a long-lasting shock wave to an engineering target considering the ambient temperature includes the following steps: Step 1: calibrate the parameters of the normal temperature constitutive model of the engineering target material; Step 2: Based on the parameters of the normal temperature constitutive model, a numerical simulation model of the engineering target normal temperature long-lasting explosion is established; Step 3: calibrate the constitutive model parameters at different temperatures of the engineering target; Step 4: Based on the constitutive model parameters at different temperatures, a numerical simulation model of explosions at different temperatures of the engineering target is established. The explosion process of the engineering target at different temperatures, different overpressures P, and different impulses I is numerically simulated to obtain the numerical simulation damage data of the engineering target at different temperatures. Step 5: Define damage levels and different critical damage states based on the project's target characteristics, classify the numerical simulation damage data at different temperatures into different damage levels, and find damage criterion criteria under different critical damage states. Substitute the numerical simulation damage data at different temperatures into the classic PI curve expression for fitting, and obtain the asymptotic overpressure and asymptotic impulse of the critical lines of different damage levels at different temperatures, and establish the PI curve damage criterion expression at different temperatures. Step 6: Analyze the correlation between asymptotic overpressure and asymptotic impulse and temperature. Establish temperature empirical formulas for asymptotic overpressure and asymptotic impulse at different temperatures through parameter fitting. Substitute these formulas into the damage criterion expressions of the PI curve at different temperatures to obtain a damage criterion that takes temperature effects into account. Step seven: Based on the damage criterion taking into account the temperature effect, complete the damage assessment work according to the characteristics of the engineering target to be assessed and the ambient temperature.

[0009] Preferably, in step 1, calibrating the parameters of the normal-temperature constitutive model of the engineering target material includes the following steps: Step 1.1: Conduct static and dynamic tests on the target engineering material at room temperature to obtain room-temperature mechanical test data; or collect publicly available room-temperature mechanical test data; Step 1.2: Establish a normal-temperature constitutive model based on normal-temperature mechanical test data and calibrate the parameters of the normal-temperature constitutive model; Step 1.3, using the calibrated parameters of the normal temperature constitutive model to establish a normal temperature mechanical numerical simulation model, and obtaining normal temperature mechanical numerical simulation data through numerical simulation; Step 1.4: If the error between the room-temperature mechanical test data and the room-temperature mechanical numerical simulation data is within 20%, save the room-temperature constitutive model parameters and the room-temperature mechanical numerical simulation model; otherwise, recalibrate the room-temperature constitutive model parameters and return to step 1.3.

[0010] Preferably, the step 2 of establishing a numerical simulation model for a long-lasting explosion at room temperature for an engineering target comprises the following steps: Step 2.1. Select the type of engineering target to be studied, conduct a room temperature long-lasting explosion test or collect publicly available data to obtain damage data from the room temperature long-lasting explosion test; Step 2.2: Establish a numerical simulation model for a long-lasting explosion at room temperature, and obtain numerical simulation damage data for a long-lasting explosion at room temperature through numerical simulation. Step 2.3: If the error between the damage data of the long-lasting explosion test at room temperature and the damage data of the long-lasting explosion numerical simulation at room temperature is within 20%, save the long-lasting explosion numerical simulation model at room temperature; otherwise, recalibrate the parameters of the long-lasting explosion numerical simulation model at room temperature and return to step 2.2.

[0011] Preferably, the step 3 of calibrating the constitutive model parameters of the engineering target at different temperatures includes the following steps: Step 3.1, conduct static tests and dynamic tests on the engineering target material at different temperatures to obtain mechanical test data at different temperatures; Step 3.2: Establish constitutive models at different temperatures based on mechanical test data at different temperatures, and calibrate parameters of constitutive models at different temperatures; Step 3.3, using the calibrated constitutive model parameters at different temperatures to establish a numerical simulation model of mechanical properties at different temperatures, and obtaining numerical simulation data of mechanical properties at different temperatures through numerical simulation; Step 3.4: If the error between the different-temperature mechanical test data and the different-temperature mechanical numerical simulation data is within 20%, save the different-temperature constitutive model parameters and the different-temperature mechanical numerical simulation model; otherwise, recalibrate the different-temperature constitutive model parameters and return to step 3.3.

[0012] Preferably, the step 7 of completing the damage assessment according to the characteristics of the engineering target to be assessed and the ambient temperature includes the following steps: Step 7.1. Determine damage criteria that take temperature effects into account based on the type of engineering target to be struck and the ambient temperature, and plot the damage criteria that take temperature effects into account on a PI curve. Step 7.2: Determine the required damage level based on strategic intent. Based on the required damage level and the damage criterion considering temperature effects, determine the required overpressure P and impulse I ranges for the explosion. Step 7.3: Determine the ammunition type and parameters based on the overpressure P and impulse I ranges.

[0013] Compared with the prior art, the present invention has the following beneficial effects: This invention eliminates the need for long-duration, high-fidelity shock wave simulations, which are extremely difficult to achieve in physical testing (such as high-yield field testing or large, constant-temperature or variable-temperature shock tubes requiring extreme modification). By leveraging advanced numerical simulation techniques and algorithms, it efficiently and cost-effectively simulates the process of long-duration explosive shock wave loads with various waveform characteristics acting on structures. This effectively addresses the core bottlenecks of existing physical simulation technologies, including high cost, high risk, high difficulty, and the inability to control a wide temperature range, significantly reducing the assessment threshold and cycle time. The invention is capable of quantitatively assessing damage to engineering targets over a wide temperature range, particularly suitable for extremely cold and low-temperature environments. This enables precise resource allocation in the diverse environments of real battlefields (such as polar, alpine, and mountainous regions), providing a solid engineering science foundation for command decision-making, effectiveness assessment, and subsequent strike optimization. This invention eliminates the need for high-risk, ultra-long-duration field explosion tests or the high-risk testing required to integrate complex temperature control systems into existing shock tubes. The present invention is mainly implemented through numerical methods, avoiding the huge safety hazards, extreme construction difficulties and maintenance problems (such as material thermal stress, sealing failure, control system complexity, etc.) existing in physical experiments. The evaluation process is safe, controllable and easy to implement. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is an overall flow chart of the method according to an embodiment of the present invention; Figure 2 This is a flow chart of calibrating parameters of a normal temperature constitutive model according to an embodiment of the present invention; Figure 3 This is a flow chart of establishing a numerical simulation model for a room temperature, long-lasting explosion according to an embodiment of the present invention; Figure 4 This is a flow chart for calibrating constitutive model parameters at different temperatures according to an embodiment of the present invention; Figure 5 A flowchart of establishing a numerical simulation model for explosions at different temperatures according to an embodiment of the present invention; Figure 6 A flowchart of establishing different temperature damage criteria and calculation equations according to an embodiment of the present invention; Figure 7 A flowchart of establishing a damage criterion considering temperature effects according to an embodiment of the present invention; Figure 8 This is a schematic diagram of the results of a static test at room temperature according to an embodiment of the present invention; Figure 9 This is a schematic diagram of the results of a room temperature kinetic test of an embodiment of the present invention; Figure 10 Schematic diagram of a static numerical simulation model according to an embodiment of the present invention; Figure 11 Schematic diagram of the dynamic numerical simulation model of the embodiment of the present invention, wherein Figure 11(a) is a static numerical simulation model, where Figure 11 (b) Dynamic numerical simulation model; Figure 12 Schematic diagram of comparison between static test and numerical simulation of an embodiment of the present invention; Figure 13 A schematic diagram of a review of the dynamics test and numerical simulation errors of an embodiment of the present invention; Figure 14 Schematic diagram showing a comparison between a long-lasting explosion shock wave test and a numerical simulation of a shock tube according to an embodiment of the present invention; Figure 15 Schematic diagram of error analysis of tests and numerical simulations at different strain rates and temperatures according to an embodiment of the present invention; Figure 16 A schematic diagram of a triangular wave load according to an embodiment of the present invention; Figure 17 PI curve schematic diagram at different temperatures according to an embodiment of the present invention; Figure 18 Graph showing the variation of the moderate failure overpressure asymptote and impulse asymptote values ​​with temperature in an embodiment of the present invention; Figure 19 Graph showing the variation of the severe failure overpressure asymptote and impulse asymptote values ​​with temperature for an embodiment of the present invention; Figure 20 This is a graph showing how the complete destruction overpressure asymptote and impulse asymptote values ​​vary with temperature in an embodiment of the present invention. DETAILED DESCRIPTION

[0015] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0016] The engineering target mainly made of concrete materials is the foundation bearing system widely used in civil, industrial and military buildings. Its explosion-proof safety assessment has great practical significance. This embodiment uses concrete materials for illustration.

[0017] like Figure 1-7 As shown in FIG, a method for assessing damage to an engineering target under the action of a long-lasting explosion shock wave taking into account the ambient temperature includes the following steps: First, a numerical simulation model of room-temperature mechanics is established.

[0018] Step 1.1: Conduct static and dynamic tests on concrete materials at room temperature to obtain room-temperature mechanical test data; or collect publicly available room-temperature mechanical test data.

[0019] The tests specifically include static and dynamic testing of C40 concrete components at room temperature. Static testing can be performed using an MTS universal mechanical testing machine, such as the RMT-150C rock mechanics testing machine, while dynamic testing typically utilizes a split-Hopkinson bar tester. Room-temperature static and dynamic testing are conventional and established testing techniques.

[0020] The room temperature mechanical test data includes: stress-strain curves of room temperature static mechanical tests, such as Figure 8 As shown; and the stress-strain curve of the room temperature dynamic test, as shown Figure 9 shown.

[0021] Step 1.2: Establish a normal-temperature constitutive model based on normal-temperature mechanical test data and calibrate the parameters of the normal-temperature constitutive model.

[0022] The normal temperature constitutive model refers to a constitutive model of concrete material that takes into account the strain rate effect at room temperature. Specific examples of the constitutive model include the HJC (Holmquist-Johnson-Cook) constitutive model and the CDP (Concrete Damaged Plasticity) constitutive model, which are all commonly used concrete constitutive models. Their parameter calibration is a mature method and will not be repeated here.

[0023] The parameters of the normal temperature constitutive model include elastic modulus, compressive strength, etc.

[0024] Step 1.3: Use the calibrated parameters of the normal-temperature constitutive model to establish a normal-temperature mechanical numerical simulation model, and obtain normal-temperature mechanical numerical simulation data through numerical simulation.

[0025] The normal temperature mechanical numerical simulation refers to: using numerical simulation software to model the concrete material, using the normal temperature constitutive model parameters as the preset parameters of the computer simulation, and performing computer numerical simulation of normal temperature static tests (uniaxial compression) and dynamic tests (Hopkinson bar tests) to obtain normal temperature mechanical numerical simulation data.

[0026] The model of static numerical simulation is as follows Figure 10 As shown in the figure, the model of dynamic numerical simulation is as follows Figure 11 The elastic modulus, compressive strength and other parameters adopt the parameters of the normal temperature constitutive model.

[0027] Currently, mechanical numerical simulation software is relatively mature, such as ABAQUS finite element analysis software and LS-DYNA finite element software. The focus of this invention is to use calibrated constitutive model parameters to carry out numerical simulation. Other numerical simulation processes, such as geometric modeling, meshing, boundary conditions, and loading methods, are all existing technologies and will not be described in detail here. At the same time, commonly used finite element numerical simulation software such as ABAQUS and LS-DYNA include commonly used concrete constitutive models, eliminating the need for secondary development.

[0028] Step 1.4: Compare the room-temperature mechanical test data and the room-temperature mechanical numerical simulation data to verify the reliability of the numerical simulation results. If the error between the room-temperature mechanical test data and the room-temperature mechanical numerical simulation data is within 20%, it is within a reasonable range, and the room-temperature constitutive model parameters and the room-temperature mechanical numerical simulation model are saved; otherwise, re-fine-tune and calibrate the room-temperature constitutive model parameters and return to step 1.3.

[0029] Because concrete materials themselves are heterogeneous and mechanical testing errors occur, concrete mechanical tests have a certain degree of discreteness. An error of less than 20% is generally considered reasonable. If the error is within a reasonable range, the normal-temperature constitutive model established in this step is considered reasonable. If the error exceeds 20%, the solution is usually to fine-tune the constitutive model parameters within the error range. This is also a common method for numerical simulation and will not be discussed here.

[0030] Secondly, a numerical simulation model for long-lasting explosion at room temperature was established. The steps are as follows: Step 2.1. Select the type of engineering target to be studied, conduct room-temperature explosion tests or collect publicly available data to obtain damage data from room-temperature, long-duration explosion tests.

[0031] The engineering target type refers to beams, slabs, columns, walls, and the like. In this embodiment, the engineering target type is a cross-beam-slab combination. The normal-temperature explosion test refers to the study of shock wave damage from a long-lasting shock tube explosion under normal temperature conditions. The damage data includes the deflection-to-span ratio (the ratio of deflection to span, with deflection measured using a displacement sensor) under the current explosion conditions (defined by overpressure P and impulse I).

[0032] Specifically, the engineering goal of this embodiment is to select a cross-beam-slab composite structure made of concrete material, and conduct a long-lasting explosion shock wave damage test study on the beam-slab composite structure of typical building components.

[0033] The long-lasting explosion shock wave damage test is a commonly used test method in this field. Usually, the selected engineering target is placed at the mouth of the explosion shock tube, and the long-lasting explosion shock wave generated by the explosion shock tube is used to apply a load to the engineering target. The specific test method can be referred to Chinese patents CN119294149A, CN119503158A, or other public books, which will not be repeated in this article.

[0034] Step 2.2: Establish a numerical simulation model for a room-temperature, long-lasting explosion and obtain damage data through numerical simulation. Set the load source parameters for the room-temperature, long-lasting explosion numerical simulation model to the same load source as used in the room-temperature explosion test or collected, publicly available data in Step 2.1. Set the engineering target constitutive parameters for the room-temperature, long-lasting explosion numerical simulation model to the room-temperature constitutive model parameters saved in Step 1.4.

[0035] The room-temperature, long-lasting explosion numerical simulation model specifically models and numerically simulates the damage process of a beam-slab composite structure caused by a long-lasting explosion at room temperature. The parameters of the room-temperature, long-lasting explosion numerical simulation model primarily include load source parameters and engineering target constitutive parameters.

[0036] The same shock wave overpressure P and impulse I as in step 2.1 were used as the load source parameters for the normal-temperature explosion numerical simulation. The concrete material constitutive model used in the normal-temperature explosion numerical simulation employed the normal-temperature constitutive model parameters saved in step 1.4. Other geometric modeling, meshing, and boundary condition settings were all based on existing techniques and were set up using the same dimensions as in step 2.1.

[0037] Step 2.3: Compare the damage data from the long-lasting explosion test at room temperature with the damage data from the numerical simulation at room temperature. If the error between the damage data from the long-lasting explosion test at room temperature and the damage data from the numerical simulation at room temperature is within 20%, save the numerical simulation model for the long-lasting explosion at room temperature. Otherwise, re-fine-tune and calibrate the parameters of the numerical simulation model for the long-lasting explosion at room temperature, and return to step 2.2.

[0038] The "fine-tuning of the parameters of the numerical simulation model for long-lasting explosion at room temperature" usually uses methods such as adjusting boundary conditions and contact algorithm parameters to correct the numerical simulation results, which is a commonly used method for numerical simulation in this field.

[0039] Data comparison Figure 14 As shown in the figure, through the comparison of displacement data, it is found that the peak value of the experimental displacement curve is in good agreement with the numerical simulation. Therefore, it is determined that the current numerical simulation model of long-lasting explosion at room temperature is more credible.

[0040] The third step is to calibrate the constitutive model parameters at different temperatures. The steps are as follows: Step 3.1: Using the same static / dynamic test equipment and test methods as Step 1.1, add a temperature-controlled test chamber to the original test. Before the test, control the temperature of the test chamber to set the test temperatures to 0°C, -10°C, -20°C, -30°C, -40°C, and -50°C. After the temperature stabilizes, conduct static and dynamic tests on the concrete material at different temperatures to obtain mechanical test data at different temperatures.

[0041] Step 3.2: Establish constitutive models at different temperatures based on mechanical test data at different temperatures, and calibrate the parameters of the constitutive models at different temperatures.

[0042] In this embodiment, the parameters of the HJC constitutive model of concrete material are calibrated at 0°C, -10°C, -20°C, -30°C, -40°C and -50°C respectively.

[0043] Step 3.3: Use the calibrated constitutive model parameters at different temperatures to establish a numerical simulation model of mechanical properties at different temperatures, and obtain numerical simulation data of mechanical properties at different temperatures through numerical simulation.

[0044] Step 3.4: Compare the mechanical test data at different temperatures with the mechanical numerical simulation data at different temperatures to verify the reliability of the numerical simulation results. If the error between the mechanical test data at different temperatures and the mechanical numerical simulation data at different temperatures is within 20%, it is within a reasonable range, and the constitutive model parameters at different temperatures and the mechanical numerical simulation model at different temperatures are saved; otherwise, re-fine-tune and calibrate the constitutive model parameters at different temperatures and return to step 3.3.

[0045] Fourthly, a numerical simulation model of explosions at different temperatures is established.

[0046] Step 4.1: Establish a numerical simulation model for explosions at different temperatures. Specifically, replace the load source parameters of the normal temperature long-term explosion numerical simulation model with a triangular wave load, and replace the engineering target constitutive parameters of the normal temperature long-term explosion numerical simulation model with the constitutive model parameters at different temperatures, thereby obtaining the numerical simulation model for explosions at different temperatures.

[0047] In this field, a hypothetical triangular overpressure time-history curve is often used to simplify the actual blast load overpressure time-history curve. For example, in the Tianjin University doctoral dissertation "Dynamic Response Behavior and Damage Mechanism of Reinforced Concrete Structures Under Explosive Loads," the positive overpressure component of the blast load can be simplified as a triangular load that rises instantaneously from zero to a maximum value and then decreases linearly to zero. The parameters describing this load are the wavefront arrival time, the positive overpressure duration, and the positive overpressure peak.

[0048] For the numerical simulation of explosions at different temperatures, since the existing technical data lacks relevant experimental parameter references, the numerical simulation of the present invention uses triangular waves to describe overpressure and impulse, such as Figure 16This is a commonly used method in related research and will not be described in detail here.

[0049] Step 4.2: Based on the numerical simulation model of explosions at different temperatures, the explosion process of the beam-slab composite structure at different temperatures, overpressures P, and impulses I is numerically simulated to obtain the numerical simulation damage data at different temperatures.

[0050] The numerical simulation damage data at different temperatures refers to the deflection-span ratio under different temperatures, different overpressures P and impulses I. Figure 17 As shown in the figure, each scattered point represents different temperature, overpressure P, impulse I and other conditions selected and numerically simulated in this embodiment.

[0051] Fifth, establish different temperature damage criteria and calculation equations. The steps are as follows: Step 5.1. Based on the structural characteristics of the beam-slab combination, this embodiment uses the deflection-span ratio as the damage criterion to classify the damage levels into mild damage, moderate damage, severe damage, and complete damage. The critical state between different damage levels is called the "critical damage state", which includes moderate damage critical, severe damage critical, and complete damage critical.

[0052] Specifically, "a small amount of concrete delamination, cracks or local deformation in the structure, no obvious overall deformation, the overall structure is intact, and its bearing capacity is not affected, and only simple repair is needed" is defined as slight damage; "concrete peeling occurs on the back of the slab, a certain number of cracks appear, the steel bars are partially exposed, the concrete slab has overall small-area damage, the cross beams have less damage, and can be repaired and continued in a short time" is defined as moderate damage; "the slab structure has large deformation or a large number of cracks, the whole structure has continuous peeling and crushing, the steel mesh has bending damage, and the bearing capacity has basically been lost. The beam structure has a certain degree of bending damage, but still has a certain integrity and bearing capacity, and there is a possibility of repair" is defined as severe damage; "both the cross beam structure and the slab structure have obvious collapse and penetration, severe crushing, a large number of bending and fractures in the steel cage and steel mesh, and the bearing capacity has been completely lost, its function has failed, and the value of repair has been lost" is defined as complete damage.

[0053] In this embodiment, the critical state between mild damage and moderate damage is defined as moderate damage critical, the critical state between moderate damage and severe damage is defined as severe damage critical, and the critical state between severe damage and complete damage is defined as complete damage critical.

[0054] Step 5.2: Divide the numerical simulation damage data of different temperatures obtained in step 4.2 into different damage levels according to the definition of damage level, and find the deflection-span ratio under different critical damage states.

[0055] Concrete structures have different constitutive parameters at different temperatures, and therefore exhibit different mechanical responses under different overpressures P and different durations of explosion shock waves. This example uses 550 sets of numerical simulations to batch calculate and derive the critical values ​​for moderate, severe, and complete damage of a cross-beam-slab composite structure at different temperatures. The deflection-span ratios corresponding to different levels of damage at different temperatures are calculated, as shown in the following table, "Critical Values ​​for Different Damage Levels of Cross-Beam-Slab Composite Structures at Different Temperatures": Different critical values ​​of failure of cross beam-slab composite structures at different temperatures

[0056] Temperature (℃) Critical deflection-span ratio for moderate damage (%) Critical deflection-span ratio for severe damage (%) Complete failure critical deflection span ratio (%) 30 7.6 20.9 30.8 0 4.2 12.1 26.3 -10 4.1 10.4 27.1 -20 2.3 13.3 35.0 -30 3.4 16.8 35.5 -40 3.0 12.7 43.2 -50 4.3 10.4 16.5 Step 5.3: Process the data at different temperatures one by one, substitute the numerical simulation damage data at different temperatures into the classic PI curve expression for fitting, obtain the asymptotic overpressure and asymptotic impulse of the critical lines of different damage levels at different temperatures, and establish the PI curve damage criterion expression at different temperatures.

[0057] The PI curve damage criterion expressions at different temperatures refer to PI curve expressions of moderate / severe / complete destruction critical states at different temperatures.

[0058] Specifically: The classic PI curve expression is:

[0059] In the above formula, P is overpressure, I is impulse, and P sn is the asymptotic overpressure, I sn is the asymptotic impulse.

[0060] The method of "determining the asymptotic overpressure and asymptotic impulse of the damage level critical line based on numerical simulation damage data at different temperatures" belongs to the prior art, and reference can be made to paragraphs

[0054] -

[0058] of Chinese patent CN120355776A.

[0061] The conventional method for establishing PI curves is relatively mature. You can refer to the methods in Tianjin University's doctoral dissertation "Dynamic Response Behavior and Damage Failure Mechanism of Reinforced Concrete Structures under Explosive Loads" (Shi Yanchao, 2009) and the National University of Defense Technology's doctoral dissertation "Study on the Damage Effects and Evaluation Methods of Reinforced Concrete Components under Explosive Loads" (Wang Wei, 2012).

[0062] The PI curve damage criterion at different temperatures established in this embodiment is as follows: Figure 17 The expressions of the curves shown are as follows: When Tn=30℃:

[0063] When Tn=0℃:

[0064] When Tn=-10℃:

[0065] When Tn=-20℃:

[0066] When Tn=-30℃:

[0067] When Tn=-40℃:

[0068] When Tn=-50℃:

[0069] The sixth aspect is to establish a damage criterion that takes temperature effects into account. The steps are as follows: Step 6.1: Analyze the damage criterion expression of the PI curve at different temperatures established in the fifth aspect, and analyze the asymptotic overpressure P sn and progressive impulse I sn The temperature empirical formulas of progressive overpressure and progressive impulse are established through parameter fitting based on the correlation between the temperature and progressive overpressure.

[0070] In this embodiment, moderate damage asymptotic overpressure and moderate damage asymptotic impulse The value changes with temperature as follows Figure 18 As shown; severe damage asymptotic overpressure and severe damage asymptotic impulse The value changes with temperature as follows Figure 19 As shown, the complete destruction of the asymptotic overpressure and the asymptotic impulse of complete destruction The value changes with temperature as follows Figure 20 The corresponding expression is as follows: The moderate failure asymptotic overpressure is obtained by fitting and moderate damage asymptotic impulse The specific piecewise function expression is as follows:

[0071]

[0072] The severe damage asymptotic overpressure is obtained by fitting and severe damage asymptotic impulse The specific piecewise function expression is as follows:

[0073]

[0074] The complete failure asymptotic overpressure is obtained by fitting and the asymptotic impulse of complete destruction The specific piecewise function expression is as follows:

[0075]

[0076] Step 6.2: Substitute the temperature empirical formulas for each progressive overpressure and progressive impulse in step 6.1 into the PI curve damage criterion expression at different temperatures in step 5.3 to obtain the PI curve expression considering the temperature effect, that is, the damage criterion considering the temperature effect.

[0077] The specific expression of the damage criterion considering the temperature effect is as follows: (1) PI curve function expression considering the temperature effect of moderate damage criticality:

[0078] (2) PI curve function expression considering temperature effect for severe damage criticality:

[0079] (3) Completely destroy the PI curve function expression considering the temperature effect:

[0080] According to the specific ambient temperature, the temperature parameter is substituted into the above expression to obtain the specific PI curve expressions corresponding to moderate damage, severe damage, and complete damage.

[0081] Seventh, the damage assessment is completed based on the engineering target characteristics and ambient temperature of the target to be assessed. The steps are as follows: Step 7.1: Determine the damage criterion that takes temperature effects into account based on the type of engineering target to be struck and the ambient temperature, and plot it on the PI curve.

[0082] Specifically, the corresponding damage criterion expression considering the temperature effect is selected according to the type of engineering target. The ambient temperature is substituted into the above expression to obtain the moderate / severe / complete damage curve of the engineering target at the current temperature, which is then plotted on the PI curve chart.

[0083] Step 7.2: Determine the required damage level based on the strategic intent. Based on the required damage level and the damage criteria, determine the range of overpressure P and impulse I required for the explosion.

[0084] For example, if the strategic intent is to paralyze the engineering target to be struck, it is determined that the target must be struck to a state of severe damage. Then, referring to the damage criteria determined in step 7.1, the region corresponding to the severe damage state and the corresponding overpressure P and impulse I ranges are found on the PI curve.

[0085] Step 7.3: Determine the ammunition type and parameters based on the overpressure P and impulse I ranges.

[0086] How to determine the type and parameters of ammunition from the range of overpressure P and impulse I involves ammunition science, and the current research is relatively mature, such as the CONWEP explosion load calculation method. This method is derived from the explosion load calculation method of US military test data and is used for explosion calculations in free air fields and close-range explosions. Therefore, the relevant calculation process will not be repeated here.

Claims

1. A method for assessing damage to engineering targets caused by long-lasting shock waves taking into account ambient temperature, characterized in that: The steps include: Step 1: calibrate the parameters of the normal temperature constitutive model of the engineering target material; Step 2: Based on the parameters of the normal temperature constitutive model, a numerical simulation model of the engineering target normal temperature long-lasting explosion is established; Step 3: calibrate the constitutive model parameters at different temperatures of the engineering target; Step 4: Based on the constitutive model parameters at different temperatures, a numerical simulation model of explosions at different temperatures of the engineering target is established. The explosion process of the engineering target at different temperatures, different overpressures P, and different impulses I is numerically simulated to obtain the numerical simulation damage data of the engineering target at different temperatures. Step 5: Define damage levels and different critical damage states based on the project's target characteristics, classify the numerical simulation damage data at different temperatures into different damage levels, and find damage criterion criteria under different critical damage states. Substitute the numerical simulation damage data at different temperatures into the classic PI curve expression for fitting, and obtain the asymptotic overpressure and asymptotic impulse of the critical lines of different damage levels at different temperatures, and establish the PI curve damage criterion expression at different temperatures. Step 6: Analyze the correlation between asymptotic overpressure and asymptotic impulse and temperature. Establish temperature empirical formulas for asymptotic overpressure and asymptotic impulse at different temperatures through parameter fitting. Substitute these formulas into the damage criterion expressions of the PI curve at different temperatures to obtain a damage criterion that takes temperature effects into account. Step seven: Based on the damage criterion taking into account the temperature effect, complete the damage assessment work according to the characteristics of the engineering target to be assessed and the ambient temperature.

2. The method for assessing damage to engineering targets caused by long-lasting shock waves taking into account ambient temperature according to claim 1 is characterized in that: In step 1, calibrating the parameters of the normal temperature constitutive model of the engineering target material includes the following steps: Step 1.1: Conduct static and dynamic tests on the target engineering material at room temperature to obtain room-temperature mechanical test data; or collect publicly available room-temperature mechanical test data; Step 1.2: Establish a normal-temperature constitutive model based on normal-temperature mechanical test data and calibrate the parameters of the normal-temperature constitutive model; Step 1.3, using the calibrated parameters of the normal temperature constitutive model to establish a normal temperature mechanical numerical simulation model, and obtaining normal temperature mechanical numerical simulation data through numerical simulation; Step 1.4: If the error between the room-temperature mechanical test data and the room-temperature mechanical numerical simulation data is within 20%, save the room-temperature constitutive model parameters and the room-temperature mechanical numerical simulation model; otherwise, recalibrate the room-temperature constitutive model parameters and return to step 1.

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3. The method for assessing damage to engineering targets caused by long-lasting shock waves taking into account ambient temperature according to claim 2 is characterized in that: Step 2 of establishing a numerical simulation model for a long-lasting explosion at room temperature for an engineering target includes the following steps: Step 2.

1. Select the type of engineering target to be studied, conduct a room temperature long-lasting explosion test or collect publicly available data to obtain damage data from the room temperature long-lasting explosion test; Step 2.2: Establish a numerical simulation model for a long-lasting explosion at room temperature, and obtain numerical simulation damage data for a long-lasting explosion at room temperature through numerical simulation. Step 2.3: If the error between the damage data of the long-lasting explosion test at room temperature and the damage data of the long-lasting explosion numerical simulation at room temperature is within 20%, save the long-lasting explosion numerical simulation model at room temperature; otherwise, recalibrate the parameters of the long-lasting explosion numerical simulation model at room temperature and return to step 2.

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4. The method for assessing damage to engineering targets caused by long-lasting shock waves taking into account ambient temperature according to claim 3 is characterized in that: Step 3 of calibrating the constitutive model parameters of the engineering target at different temperatures includes the following steps: Step 3.1, conduct static tests and dynamic tests on the engineering target material at different temperatures to obtain mechanical test data at different temperatures; Step 3.2: Establish constitutive models at different temperatures based on mechanical test data at different temperatures, and calibrate parameters of constitutive models at different temperatures; Step 3.3, using the calibrated constitutive model parameters at different temperatures to establish a numerical simulation model of mechanical properties at different temperatures, and obtaining numerical simulation data of mechanical properties at different temperatures through numerical simulation; Step 3.4: If the error between the different-temperature mechanical test data and the different-temperature mechanical numerical simulation data is within 20%, save the different-temperature constitutive model parameters and the different-temperature mechanical numerical simulation model; otherwise, recalibrate the different-temperature constitutive model parameters and return to step 3.

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5. The method for assessing damage to engineering targets caused by long-lasting shock waves taking into account ambient temperature according to claim 1 is characterized in that: Step 7, based on the characteristics of the project to be assessed and the ambient temperature, completes the damage assessment work, including the following steps: Step 7.

1. Determine damage criteria that take temperature effects into account based on the type of engineering target to be struck and the ambient temperature, and plot the damage criteria that take temperature effects into account on a PI curve. Step 7.2: Determine the required damage level based on strategic intent. Based on the required damage level and the damage criterion considering temperature effects, determine the range of overpressure P and impulse I required for the explosion. Step 7.3: Determine the ammunition type and parameters based on the overpressure P and impulse I ranges.

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