Method for evaluating damage of engineering target by long-duration shock wave considering environmental temperature

Abstract

The present application belongs to the field of electric digital data processing, and relates to a long duration shock wave damage evaluation method for engineering targets considering environmental temperature, calibration of normal temperature constitutive model parameters; establishment of a normal temperature long duration explosion numerical simulation model; calibration of different temperature constitutive model parameters; establishment of a different temperature explosion numerical simulation model, numerical simulation of the explosion process to obtain different temperature numerical simulation damage data; substitution of the simulated damage data into a classical P-I curve expression fitting to establish a P-I curve damage criterion expression at different temperatures; bringing of a temperature empirical formula into the P-I curve damage criterion expression at different temperatures to obtain a damage criterion considering temperature effect; and based on the damage criterion considering temperature effect, completion of damage evaluation work according to the characteristics of the engineering target to be evaluated and the environmental temperature. The present application can efficiently complete damage evaluation of engineering targets under the action of long duration explosion shock waves through numerical simulation technology and algorithms without relying on physical tests.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of explosion damage and digital data processing, and particularly relates to a method for damage assessment of long-duration shock wave on engineering targets considering environmental temperature. BACKGROUND

[0002] In the modern military decision-making system, scientific and quantitative damage assessment is a key support link for the victory of war. At present, one of the pre-war damage assessment work is to determine the type of ammunition according to the strategic intent. For example, if the current strategic intent is to strike the engineering target to the state of "heavy damage", then according to the strategic intent and the physical properties of the engineering target, the required ammunition type and ammunition parameters are determined in reverse, so as to provide accurate decision-making basis for combat command, evaluate the combat effectiveness, and provide core engineering reference for the optimization of subsequent strike strategy.

[0003] With the wide application of high-energy explosives and the increasing trend of military use of underground space, the damage of long-duration explosion shock wave (usually refers to the explosion duration > 30 ms, up to seconds) to building structures needs to be studied. When long-duration explosion shock wave acts on building structures, it will induce significant cumulative effect of overall dynamic response. This continuous load driven structure system undergoes a complex multi-stage nonlinear failure process: from the initiation and evolution of material damage, to the instability of connecting nodes, and finally possibly leading to the overall collapse of the structure. Its failure mechanism is highly complex and difficult to predict. Most of the existing technologies are based on short-duration (millisecond level) contact explosion local damage effect for evaluation, which cannot be applied to the damage assessment of long-duration explosion shock.

[0004] In addition, there are significant temperature changes in battlefield environments (especially in polar, cold and mountainous regions). The mechanical properties of building materials, especially reinforced concrete materials (Reinforced Concrete, hereinafter referred to as RC), are highly sensitive to environmental temperature. Temperature changes will significantly change the constitutive relationship, dynamic strength, stiffness and energy dissipation mechanism of materials such as concrete and steel. Low temperature environment will exacerbate the brittleness of concrete and deteriorate the steel-concrete cooperative performance, thereby significantly affecting the dynamic response characteristics, damage development path and final failure mode of RC structure. The existing damage assessment methods are generally based on normal temperature conditions, and the decisive role of the key variable of environmental temperature is seriously ignored, resulting in significant deviation in the assessment results in cold, variable temperature and other special environments, which endangers the accuracy and reliability of decision-making.

[0005] Traditional explosion test method is difficult to directly realize long duration, different temperature explosion test, for example, large equivalent field test can produce long duration explosion shock wave, but it needs very high explosion equivalent (tens to hundreds of kilograms), which leads to strict site safety requirements, extremely high cost, huge destructive, and the target environment temperature is difficult to control and maintain. In the laboratory, the explosion shock tube technology is usually used, which can obtain long duration explosion shock wave with a small amount of explosive. However, in order to meet the wide temperature range (especially low temperature / high cold environment) test requirements, a special constant temperature / variable temperature large shock tube facility needs to be built, which has extremely high design, construction and maintenance cost, and great engineering difficulty. Moreover, integrating a large-scale, high-performance temperature control system on the existing shock tube system has uncontrollable safety hazards.

[0006] In summary, accurately quantifying and evaluating the damage degree of engineering targets under the action of long duration explosion shock wave in different temperature real battlefield environment (especially represented by high cold and low temperature) is faced with double severe challenges: on the one hand, the high-fidelity technology of physical simulation of long duration explosion shock wave is limited; on the other hand, it is extremely difficult to obtain reliable data of the influence mechanism of the coupling effect of environmental temperature and long duration explosion shock wave on material dynamic performance and structure response by using existing test technology. Therefore, it is urgent to develop a new method for quantitatively evaluating the damage of engineering targets, which does not depend on extreme condition physical test and can effectively integrate the influence of environmental temperature and the coupling effect of long duration explosion shock wave. SUMMARY

[0007] The purpose of the present application is to solve the above-mentioned shortcomings in the prior art, and to provide a method for evaluating the damage of engineering targets considering the environmental temperature of long duration shock wave, which realizes fast and efficient damage evaluation.

[0008] In order to achieve the above-mentioned purpose, the present application adopts the following technical scheme:

[0009] The method for evaluating the damage of engineering targets considering the environmental temperature of long duration shock wave comprises the following steps:

[0010] Step 1, calibrate the normal temperature constitutive model parameters of engineering target materials;

[0011] Step 2, based on the normal temperature constitutive model parameters, establish a normal temperature long duration explosion numerical simulation model of engineering target;

[0012] Step 3, calibrate the different temperature constitutive model parameters of engineering targets;

[0013] Step 4, based on the different temperature constitutive model parameters, establish a different temperature explosion numerical simulation model of engineering target, and perform numerical simulation of the explosion process of engineering target under different temperature, different overpressure P and different impulse I, to obtain different temperature numerical simulation damage data of engineering target;

[0014] Step five, according to the characteristics of the engineering target, define the damage level and different damage critical states, divide the numerical simulation damage data at different temperatures into different damage levels, and find the damage criterion at different damage critical states; substitute the numerical simulation damage data at different temperatures into the classical P-I curve expression for fitting, obtain the asymptotic overpressure and asymptotic impulse of the critical line at different damage levels at different temperatures, and establish the P-I curve damage criterion expression at different temperatures;

[0015] Step six, analyze the correlation between the asymptotic overpressure and the asymptotic impulse and the temperature, establish the temperature empirical formula of the asymptotic overpressure and the asymptotic impulse at different temperatures through parameter fitting, and substitute it into the P-I curve damage criterion expression at different temperatures to obtain the damage criterion considering the temperature effect;

[0016] Step seven, based on the damage criterion considering the temperature effect, complete the damage assessment work according to the characteristics of the engineering target to be evaluated and the environmental temperature.

[0017] Preferably, the step one of calibrating the engineering target material constitutive model parameters at room temperature comprises the following steps:

[0018] Step 1.1, carry out statics and dynamics tests of the engineering target material at room temperature to obtain room temperature mechanics test data; or collect published room temperature mechanics test data;

[0019] Step 1.2, establish a room temperature constitutive model based on the room temperature mechanics test data, and calibrate the room temperature constitutive model parameters;

[0020] Step 1.3, establish a room temperature mechanics numerical simulation model using the calibrated room temperature constitutive model parameters, and obtain room temperature mechanics numerical simulation data through numerical simulation;

[0021] Step 1.4, if the error between the room temperature mechanics test data and the room temperature mechanics numerical simulation data is within 20%, save the room temperature constitutive model parameters and the room temperature mechanics numerical simulation model; otherwise, recalibrate the room temperature constitutive model parameters and return to step 1.3.

[0022] Preferably, the step two of establishing a room temperature long duration explosion numerical simulation model of the engineering target comprises the following steps:

[0023] Step 2.1, select the type of engineering target to be studied, carry out a room temperature long duration explosion test or collect published data, and obtain room temperature long duration explosion test damage data;

[0024] Step 2.2, establish a room temperature long duration explosion numerical simulation model, and obtain room temperature long duration numerical simulation damage data through numerical simulation;

[0025] Step 2.3, if the error between the damage data of the long-time explosion test at normal temperature and the damage data of the numerical simulation of the long-time explosion at normal temperature is within 20%, the numerical simulation model of the long-time explosion at normal temperature is saved; otherwise, the parameters of the numerical simulation model of the long-time explosion at normal temperature are recalibrated, and the step 2.2 is returned.

[0026] Preferably, the step three of calibrating the parameters of the constitutive model at different temperatures of the engineering target comprises the following steps:

[0027] Step 3.1, the static and dynamic tests of the engineering target material at different temperatures are carried out respectively, and the mechanical test data at different temperatures are obtained;

[0028] Step 3.2, the constitutive model at different temperatures is established based on the mechanical test data at different temperatures, and the parameters of the constitutive model at different temperatures are calibrated;

[0029] Step 3.3, the constitutive model at different temperatures is established based on the parameters of the constitutive model at different temperatures, and the numerical simulation data at different temperatures are obtained by numerical simulation;

[0030] Step 3.4, if the error between the mechanical test data at different temperatures and the numerical simulation data at different temperatures is within 20%, the parameters of the constitutive model at different temperatures and the numerical simulation model at different temperatures are saved; otherwise, the parameters of the constitutive model at different temperatures are recalibrated and the step 3.3 is returned.

[0031] Preferably, the step seven of completing the damage assessment according to the characteristics of the engineering target to be evaluated and the environmental temperature comprises the following steps:

[0032] Step 7.1, according to the type of the engineering target to be attacked and the environmental temperature, the damage criterion considering the temperature effect is determined, and the damage criterion considering the temperature effect is plotted in the P-I curve diagram;

[0033] Step 7.2, according to the required damage level determined according to the strategic intention, the required damage level is determined according to the damage criterion considering the temperature effect, and the required overpressure P and impulse I range of the explosion are determined;

[0034] Step 7.3, according to the overpressure P and impulse I range, the type and parameters of the ammunition are determined.

[0035] Compared with the prior art, the present application has the following beneficial effects:

[0036] The present application does not need to rely on the long duration high fidelity shock wave simulation in physical test which is extremely difficult to realize (such as large equivalent field test or constant temperature / variable temperature large scale shock tube which needs extreme modification), through advanced numerical simulation technology and algorithm, the process that long duration explosion shock wave load with various waveform characteristics acts on the structure can be simulated efficiently and at low cost, the core bottleneck of high cost, high risk, high difficulty and wide temperature range control unfeasible faced by existing physical simulation technology is effectively solved, and the evaluation threshold and period are greatly reduced. The present application has the capability of quantitative damage evaluation of engineering targets in a wide temperature range (especially suitable for cold and low temperature environment). This meets the precise configuration of resources in real battlefield variable environment (such as polar region, high cold and mountainous region), and provides a solid engineering scientific basis for command decision, efficiency evaluation and subsequent attack optimization. The present application does not need to carry out high-risk super-long duration field explosion test or high-risk test on existing shock tube integrated with complex temperature control system. The present application is mainly realized by numerical method, which avoids the great safety hidden danger, extreme construction difficulty and maintenance problem (such as material thermal stress, sealing failure and control system complexity) in physical test, and the evaluation process is safe and controllable, and convenient to implement. BRIEF DESCRIPTION OF DRAWINGS

[0037] Figure 1 The flow chart of the method of the embodiment of the present application is shown in the figure;

[0038] Figure 2 The flow chart of calibrating the normal temperature constitutive model parameters of the embodiment of the present application is shown in the figure;

[0039] Figure 3 The flow chart of establishing the normal temperature long duration explosion numerical simulation model of the embodiment of the present application is shown in the figure;

[0040] Figure 4 The flow chart of calibrating the different temperature constitutive model parameters of the embodiment of the present application is shown in the figure;

[0041] Figure 5 The flow chart of establishing the different temperature explosion numerical simulation model of the embodiment of the present application is shown in the figure;

[0042] Figure 6 The flow chart of establishing the different temperature damage criterion and calculation equation of the embodiment of the present application is shown in the figure;

[0043] Figure 7 The flow chart of establishing the damage criterion considering temperature effect of the embodiment of the present application is shown in the figure;

[0044] Figure 8 The normal temperature statics test result schematic diagram of the embodiment of the present application is shown in the figure;

[0045] Figure 9 The normal temperature dynamics test result schematic diagram of the embodiment of the present application is shown in the figure;

[0046] Figure 10 A static numerical simulation model diagram of an embodiment of the present application;

[0047] Figure 11 A dynamic numerical simulation model diagram of an embodiment of the present application, wherein Figure 11 (a) is a static numerical simulation model, wherein Figure 11 (b) is a dynamic numerical simulation model;

[0048] Figure 12 A static test and numerical simulation comparison diagram of an embodiment of the present application;

[0049] Figure 13 A dynamic test and numerical simulation error analysis diagram of an embodiment of the present application;

[0050] Figure 14 A shock tube long duration explosion shock wave test and numerical simulation comparison diagram of an embodiment of the present application;

[0051] Figure 15 A test and numerical simulation error analysis diagram of an embodiment of the present application at different strain rates and different temperatures;

[0052] Figure 16 A triangular wave load diagram of an embodiment of the present application;

[0053] Figure 17 A P-I curve diagram at different temperatures of an embodiment of the present application;

[0054] Figure 18 A moderate damage overpressure asymptote and impulse asymptote numerical value change diagram with temperature of an embodiment of the present application;

[0055] Figure 19 A severe damage overpressure asymptote and impulse asymptote numerical value change diagram with temperature of an embodiment of the present application;

[0056] Figure 20 A complete damage overpressure asymptote and impulse asymptote numerical value change diagram with temperature of an embodiment of the present application. DETAILED DESCRIPTION

[0057] In order to make the above purposes, features and advantages of the present application more obvious and easy to understand, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0058] The engineering target of concrete material is a widely used basic bearing system in civil, industrial and military buildings, and the blast safety evaluation has great practical significance, and the present embodiment selects concrete material for illustration.

[0059] As Figures 1-7As shown, the engineering target damage assessment method considering ambient temperature under long-duration explosion shock wave action comprises the following steps:

[0060] In a first aspect, a normal-temperature mechanical numerical simulation model is established.

[0061] Step 1.1, carry out static and dynamic tests of concrete materials at normal temperature to obtain normal-temperature mechanical test data; or collect public normal-temperature mechanical test data.

[0062] The test specifically includes: carrying out static and dynamic tests of C40 concrete members at normal temperature, the static test can use MTS multi-function mechanical testing machine, RMT-150C rock mechanics testing machine, etc., and the dynamic test usually uses a split Hopkinson bar test device. The normal-temperature static and dynamic tests are conventional and mature test technologies.

[0063] The normal-temperature mechanical test data include: stress-strain curves of normal-temperature static tests, as shown in Figure 8 ; and stress-strain curves of normal-temperature dynamic tests, as shown in Figure 9 .

[0064] Step 1.2, establish a normal-temperature constitutive model based on the normal-temperature mechanical test data, and calibrate parameters of the normal-temperature constitutive model.

[0065] The normal-temperature constitutive model refers to a constitutive model of concrete materials considering strain rate effect at normal temperature, and the constitutive model specifically includes, for example, HJC (Holmquist-Johnson-Cook) constitutive model, CDP (Concrete Damaged Plasticity) constitutive model, etc., which are common concrete constitutive models, and the parameter calibration is a mature method and will not be described here.

[0066] The normal-temperature constitutive model parameters include elastic modulus, compressive strength, etc.

[0067] Step 1.3, establish a normal-temperature mechanical numerical simulation model using the calibrated normal-temperature constitutive model parameters, and obtain normal-temperature mechanical numerical simulation data through numerical simulation.

[0068] The normal-temperature mechanical numerical simulation refers to modeling of concrete materials using numerical simulation software, taking the normal-temperature constitutive model parameters as preset parameters of computer simulation, and performing computer numerical simulation of normal-temperature static tests (uniaxial compression) and dynamic tests (Hopkinson bar test) to obtain normal-temperature mechanical numerical simulation data.

[0069] The model of static numerical simulation is as shown in Figure 10 , and the model of dynamic numerical simulation is as shown in Figure 11The parameters such as elastic modulus, compressive strength, etc. adopt the constitutive model parameters at normal temperature.

[0070] At present, the mechanical numerical simulation software is relatively mature, such as ABAQUS finite element analysis software, LS-DYNA finite element software, etc. The focus of the present application is to carry out numerical simulation by using the calibrated constitutive model parameters, and other numerical simulation processes, such as geometry modeling, meshing, boundary conditions, load mode, etc. are prior art, which will not be described here. At the same time, the commonly used finite element numerical simulation software such as ABAQUS, LS-DYNA, etc. contains the commonly used concrete constitutive model, which does not need to be developed again.

[0071] Step 1.4, compare the normal temperature mechanical test data and the normal temperature mechanical numerical simulation data, verify the reliability of the numerical simulation result, if the error between the normal temperature mechanical test data and the normal temperature mechanical numerical simulation data is within 20%, it is within the reasonable range, save the normal temperature constitutive model parameters and the normal temperature mechanical numerical simulation model; otherwise, readjust and calibrate the normal temperature constitutive model parameters and return to step 1.3.

[0072] Because of the non-homogeneity of the concrete material itself and the mechanical test error, the concrete mechanical test has a certain dispersion, and it is generally considered that the error within 20% is reasonable. If the error is within the reasonable range, it is considered that the normal temperature constitutive model established in this step is reasonable. If the error exceeds 20%, the method of adjusting the constitutive model parameters within the error range is usually used to solve it, which is also a common method of numerical simulation, which will not be described here.

[0073] In the second aspect, a normal temperature long duration explosion numerical simulation model is established, and the steps are as follows:

[0074] Step 2.1, select the type of engineering target to be studied, carry out normal temperature explosion test or collect published data, and obtain normal temperature long duration explosion test damage data.

[0075] The engineering target type refers to the engineering target being a beam, a plate, a column, a wall, etc. The engineering target type of the present embodiment is a cross beam-plate combination. The normal temperature explosion test refers to: carrying out shock tube long duration explosion shock wave damage test research under normal temperature conditions. The damage data includes the deflection-span ratio (deflection-span ratio is the ratio of deflection and span, deflection is obtained by displacement sensor) under the current explosion working condition (working condition is limited by overpressure P and impulse I), etc.

[0076] Specifically, the engineering target of the present embodiment selects a cross beam-plate combination structure of concrete material, and carries out long duration explosion shock wave damage test research on the typical building component beam-plate combination structure.

[0077] The long-duration explosion shock wave damage test is a commonly used test method in the art. The selected engineering target is usually placed at the mouth of the explosion shock tube, and the long-duration explosion shock wave generated by the explosion shock tube is used to apply load to the engineering target. The specific test method can be referred to in Chinese patents CN119294149A and CN119503158A, or other published books, which will not be described here.

[0078] Step 2.2, establish a normal temperature long-duration explosion numerical simulation model, and obtain normal temperature long-duration numerical simulation damage data through numerical simulation. The load source parameters of the normal temperature long-duration explosion numerical simulation model are set to be the same as the load source in the normal temperature explosion test or the collected published data in step 2.1. The engineering target constitutive parameter of the normal temperature long-duration explosion numerical simulation model is set to be the normal temperature constitutive model parameter saved in step 1.4.

[0079] The normal temperature long-duration explosion numerical simulation model specifically refers to modeling and numerically simulating the long-duration explosion shock wave damage process of the beam-slab composite structure under normal temperature conditions. The parameters of the normal temperature long-duration explosion numerical simulation model mainly include load source parameters and engineering target constitutive parameters.

[0080] The same shock wave overpressure P and impulse I as in step 2.1 are used as the load source parameters of the normal temperature explosion numerical simulation. The constitutive model of the concrete material in the normal temperature explosion numerical simulation adopts the normal temperature constitutive model parameter saved in step 1.4. Other geometric modeling, mesh division, boundary condition setting, etc. are all prior art, and are set according to the same size as in step 2.1.

[0081] Step 2.3, compare the normal temperature long-duration explosion test damage data and the normal temperature long-duration numerical simulation damage data. If the error between the normal temperature long-duration explosion test damage data and the normal temperature long-duration numerical simulation damage data is within 20%, save the normal temperature long-duration explosion numerical simulation model; otherwise, readjust the parameters of the normal temperature long-duration explosion numerical simulation model and return to step 2.2.

[0082] The "fine-tuning of normal temperature long-duration explosion numerical simulation model parameters" usually uses methods such as adjusting boundary conditions and contact algorithm parameters to correct the numerical simulation results, which is a commonly used method in the numerical simulation field.

[0083] The data comparison is as shown in the figure. Figure 14 As shown in the figure, through the displacement data comparison, it is found that the peak value of the test displacement curve is in good agreement with the numerical simulation, and therefore it is determined that the current normal temperature long-duration explosion numerical simulation model has high reliability.

[0084] In the third aspect, the parameters of the different temperature constitutive model are calibrated, and the steps are as follows:

[0085] Step 3.1, based on the same statics / dynamics test equipment and test method as step 1.1, on the basis of the original test, increase the temperature control test box, control the temperature control test box before the test, and set the test temperature to 0℃, -10℃, -20℃, -30℃, -40℃ and -50℃ respectively. After the temperature is stable, carry out static test and dynamic test of concrete material at different temperatures, and obtain different temperature mechanical test data.

[0086] Step 3.2, based on the different temperature mechanical test data, establish different temperature constitutive model, and calibrate different temperature constitutive model parameters.

[0087] In this embodiment, the parameters of the HJC constitutive model of the concrete material are calibrated at 0℃, -10℃, -20℃, -30℃, -40℃ and -50℃ respectively.

[0088] Step 3.3, using the calibrated different temperature constitutive model parameters to establish different temperature mechanical numerical simulation model, and obtaining different temperature mechanical numerical simulation data through numerical simulation.

[0089] Step 3.4, comparing different temperature mechanical test data and different temperature mechanical numerical simulation data, verifying the reliability of the numerical simulation results, if the error between different temperature mechanical test data and different temperature mechanical numerical simulation data is within 20%, it is within the reasonable range, save different temperature constitutive model parameters and different temperature mechanical numerical simulation model; otherwise, readjust and calibrate different temperature constitutive model parameters and return to step 3.3.

[0090] Fourthly, a different temperature explosion numerical simulation model is established.

[0091] Step 4.1, establish different temperature explosion numerical simulation model. Specifically: replace the load source parameters of the normal temperature long duration explosion numerical simulation model with the triangular wave load, and replace the engineering target constitutive parameters of the normal temperature long duration explosion numerical simulation model with the different temperature constitutive model parameters, that is, obtain the different temperature explosion numerical simulation model.

[0092] The actual explosion load overpressure time history curve is usually simplified by a hypothetical triangular overpressure time history curve. For example, in the doctoral thesis of Tianjin University, "Dynamic response behavior and damage and failure mechanism of reinforced concrete structures under explosion load", the positive overpressure part of the explosion load can be simplified as a triangular load which rises from zero to maximum value instantaneously and then linearly decreases to zero. The parameters describing this load are wave front arrival time, positive overpressure duration and positive overpressure peak value.

[0093] For different temperature explosion numerical simulation, since the existing technical materials lack relevant test parameter references, the numerical simulation of the present application uses a triangular wave to describe the overpressure and impulse, such as Figure 16The method is commonly used in related researches and will not be described herein.

[0094] Step 4.2, numerical simulation of the explosion process of the beam-slab composite structure under different temperatures, different overpressures P and impulses I is carried out based on a different-temperature explosion numerical simulation model, and different-temperature numerical simulation damage data is obtained.

[0095] The different-temperature numerical simulation damage data refers to the deflection-span ratio under different temperatures, different overpressures P and impulses I. Figure 17 As shown in the figure, each scatter point in the figure represents different conditions of temperature, overpressure P and impulse I selected and simulated in the embodiment.

[0096] In a fifth aspect, different-temperature damage criteria and calculation equations are established, and the steps are as follows:

[0097] Step 5.1, according to the characteristics of the beam-slab composite structure, the deflection-span ratio is used as a damage criterion in the embodiment, and the damage levels are divided into light damage, moderate damage, severe damage and complete damage; the critical state between different damage levels is referred to as a “damage critical state”, including moderate damage critical, severe damage critical and complete damage critical.

[0098] Specifically, “a small amount of concrete layer cracks, cracks or local deformation appear on the structure, the overall deformation is not obvious, the overall structure is intact, the bearing capacity is not affected, and only simple repair is required” is defined as light damage; “concrete spalling appears on the back of the plate, a certain number of cracks appear, part of the reinforcement is exposed, the concrete plate appears overall small area damage, the cross beam damage is small, and the cross beam can be repaired and used in a short time” is defined as moderate damage; “a large deformation or a large number of cracks appear on the plate structure, the overall structure appears continuous spalling and crushing, the steel mesh is bent and damaged, and the bearing capacity is basically lost, the beam structure appears 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; “obvious collapse and penetration appear on the cross beam structure and the plate structure, the steel reinforcement cage and the steel mesh are bent and fractured, the bearing capacity is completely lost, the function is failed, and the repair value is lost” is defined as complete damage.

[0099] In the embodiment, the critical state between light 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.

[0100] Step 5.2, the different-temperature numerical simulation damage data obtained in step 4.2 is divided into different damage levels according to the definition of the damage levels, and the deflection-span ratio under different damage critical states is found.

[0101] The constitutive parameters of concrete structures at different temperatures are different, so they have different mechanical responses under the action of explosion shock waves with different overpressure P and different holding time. In this embodiment, through 550 numerical simulation batch calculations, the critical values of moderate damage, severe damage and complete damage of the cross beam plate composite structure at different temperatures are obtained, and the corresponding deflection-span ratios at different temperatures and different levels are calculated, as shown in the following table "Critical values of different damages of cross beam plate composite structure at different temperatures":

[0102] Critical values of different damages of cross beam plate composite structure at different temperatures

[0103] Temperature (°C) Moderate damage critical deflection ratio (%) Severe damage critical deflection ratio (%) Complete damage critical deflection 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

[0104] Step 5.3, process the data at different temperatures one by one, substitute the numerical simulation damage data at different temperatures into the classical P-I curve expression for fitting, and obtain the asymptotic overpressure and asymptotic impulse of the critical line of different damage levels at different temperatures, and establish the P-I curve damage criterion expression at different temperatures.

[0105] The P-I curve damage criterion expression at different temperatures refers to the P-I curve expression of the moderate / severe / complete damage critical state at different temperatures.

[0106] Specifically, the classical P-I curve expression is:

[0107]

[0108] In the above formula, P is the overpressure, I is the impulse, P sn is the asymptotic overpressure, and I sn is the asymptotic impulse.

[0109] 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 can refer to paragraphs

[0054] -

[0058] of Chinese Patent CN120355776A.

[0110] The conventional method of establishing P-I curve is relatively mature, and can refer to the method in the doctoral thesis "Dynamic Response Behavior and Damage and Failure Mechanism of Reinforced Concrete Structures under Explosive Load" (Shi Yanchao, 2009) of Tianjin University and the doctoral thesis "Damage Effect and Evaluation Method of Reinforced Concrete Members under Explosive Load" (Wang Wei, 2012) of National University of Defense Technology.

[0111] The P-I curve damage criterion established by this embodiment at different temperatures is shown as each curve in Figure 17 , and the expression is as follows:

[0112] When Tn=30℃:

[0113]

[0114] When Tn=0℃:

[0115]

[0116] When Tn = -10℃:

[0117]

[0118] When Tn = -20℃:

[0119]

[0120] When Tn = -30℃:

[0121]

[0122] When Tn = -40℃:

[0123]

[0124] When Tn = -50℃:

[0125]

[0126] Sixthly, establish a damage criterion that considers temperature effects, with the following steps:

[0127] Step 6.1: Analyze the damage criterion expressions for the PI curves at different temperatures established in the fifth aspect, and analyze the asymptotic overpressure P. sn and progressive impulse I sn The correlation between temperature and parameters was investigated, and empirical temperature formulas for asymptotic overpressure and asymptotic impulse were established through parameter fitting.

[0128] In this embodiment, the asymptotic overpressure of moderate destruction and moderate damage asymptotic impulse The numerical value changes with temperature as follows: Figure 18 As shown; Severe damage asymptotic overpressure and asymptotic impulse of severe damage The numerical value changes with temperature as follows: Figure 19 As shown, the asymptotic overpressure is completely destroyed. and complete destruction of asymptotic impulse The numerical value changes with temperature as follows: Figure 20 As shown. Its corresponding expression is as follows:

[0129] The asymptotic overpressure for moderate destruction was obtained through fitting. and moderate damage asymptotic impulse The specific piecewise function expression is shown below:

[0130]

[0131]

[0132] By fitting to get heavy damage asymptotic overpressure and heavy damage asymptotic impulse The specific piecewise function expression is as follows:

[0133]

[0134]

[0135] By fitting to get complete damage asymptotic overpressure and complete damage asymptotic impulse The specific piecewise function expression is as follows:

[0136]

[0137]

[0138] Step 6.2, the temperature empirical formula of each asymptotic overpressure and asymptotic impulse in step 6.1 is brought into the P-I curve damage criterion expression at different temperatures in step 5.3, that is, the P-I curve expression considering temperature effect, that is, the damage criterion considering temperature effect.

[0139] The specific expression of the damage criterion considering temperature effect is as follows:

[0140] (1) The P-I curve function expression considering temperature effect at the moderate damage critical:

[0141]

[0142] (2) The P-I curve function expression considering temperature effect at the heavy damage critical:

[0143]

[0144] (3) The P-I curve function expression considering temperature effect at the complete damage:

[0145]

[0146] According to the specific environmental temperature, the temperature parameter is brought into the above expression, and the specific P-I curve expression corresponding to moderate damage, heavy damage and complete damage can be obtained.

[0147] In the seventh aspect, according to the engineering target characteristics and environmental temperature of the target to be evaluated, the damage evaluation work is completed, and the steps are as follows:

[0148] Step 7.1, determine the damage criterion considering temperature effect according to the type of the engineering target to be attacked and the ambient temperature, and plot it in the P-I curve diagram.

[0149] Specifically, according to the type of the engineering target, select the corresponding damage criterion expression considering temperature effect, and substitute the ambient temperature into the above expression, so as to obtain the moderate / severe / complete destruction curve of the engineering target at the current temperature, and plot it in the P-I curve diagram.

[0150] Step 7.2, determine the required damage level according to the strategic intention, and determine the required overpressure P and impulse I range according to the required damage level and the damage criterion.

[0151] For example, the strategic intention is to paralyze the engineering target to be attacked, and accordingly it is determined that the engineering target needs to be attacked to the severe damage state. Then, according to the damage criterion determined in step 7.1, the region corresponding to the severe damage state and the corresponding overpressure P and impulse I range are found in the P-I curve diagram.

[0152] Step 7.3, determine the ammunition type and ammunition parameters according to the overpressure P and impulse I range.

[0153] How to determine the ammunition type and parameters from the overpressure P and impulse I range involves ammunition science, which is currently relatively mature, such as the CONWEP explosion load calculation method, which is derived from the explosion load calculation method of the U.S. military test data, and is used for free air field explosion and close-range explosion calculation, so the relevant calculation process is not described again.

Claims

1. A method for assessing the damage of long-duration shock waves to engineering targets considering ambient temperature, characterized in that, Includes the following steps: Step 1: Calibrate the room-temperature constitutive model parameters of the target material in the project; Step 2: Based on the parameters of the room-temperature constitutive model, establish a numerical simulation model for the room-temperature long-duration explosion of the engineering target; Step 3: Calibrate the constitutive model parameters for the engineering target at different temperatures; Step 4: Based on the constitutive model parameters at different temperatures, establish numerical simulation models of explosions of engineering targets at different temperatures. Perform numerical simulations of the explosion process of engineering targets at different temperatures, different overpressures P, and different impulses I to obtain numerical simulation damage data of engineering targets at different temperatures. Step 5: Define damage levels and different critical failure states according to the characteristics of the engineering objectives. Divide the numerical simulation damage data at different temperatures into different damage levels and find the damage criteria under different critical failure states. Substitute the numerical simulation damage data at different temperatures into the classical PI curve expression for fitting to obtain the asymptotic overpressure and asymptotic impulse of the critical line 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 empirical temperature formulas for asymptotic overpressure and asymptotic impulse at different temperatures through parameter fitting, and substitute them into the damage criterion expression of the PI curve at different temperatures to obtain the damage criterion considering the temperature effect. Step 7: Based on the damage criterion considering temperature effects, complete the damage assessment according to the characteristics of the engineering target to be assessed and the ambient temperature, including the following steps: Step 7.1: Based on the type of engineering target to be attacked and the ambient temperature, determine the damage criterion that takes into account the temperature effect, and plot the damage criterion that takes into account the temperature effect on the PI curve graph. Step 7.2: Determine the required damage level based on the strategic intent, and determine the range of overpressure P and impulse I required for the explosion by referring to the damage criteria that take into account the temperature effect based on the required damage level. Step 7.3: Determine the ammunition type and ammunition parameters based on the overpressure P and impulse I ranges.

2. The method for assessing the damage to engineering targets by long-duration shock waves considering ambient temperature as described in claim 1, characterized in that, Step one, calibrating the room-temperature constitutive model parameters of the target material in the project, includes the following steps: Step 1.1: Conduct static and dynamic tests on the target 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 room-temperature constitutive model based on room-temperature mechanical test data, and calibrate the parameters of the room-temperature constitutive model; Step 1.3: Establish a room-temperature mechanical numerical simulation model using the calibrated room-temperature constitutive model parameters, and obtain room-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 the damage to engineering targets by long-duration shock waves considering ambient temperature according to claim 2, characterized in that, Step two, establishing a numerical simulation model for a long-duration, room-temperature explosion of the engineering target, includes the following steps: Step 2.1: Select the type of engineering target to be studied, conduct room temperature long-duration explosion tests or collect publicly available data to obtain damage data from room temperature long-duration explosion tests; Step 2.2: Establish a numerical simulation model for a long-duration explosion at room temperature, and obtain numerical simulation damage data for a long-duration explosion at room temperature through numerical simulation; Step 2.3: If the error between the damage data from the room temperature long-duration explosion test and the damage data from the room temperature long-duration numerical simulation is within 20%, then save the room temperature long-duration explosion numerical simulation model; otherwise, recalibrate the parameters of the room temperature long-duration explosion numerical simulation model and return to step 2.

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4. The method for assessing the damage to engineering targets by long-duration shock waves considering ambient temperature according to claim 3, characterized in that, Step three, calibrating the constitutive model parameters of the engineering target at different temperatures, includes the following steps: Step 3.1: Conduct static 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 for different temperatures based on mechanical test data at different temperatures, and calibrate the parameters of the constitutive models for different temperatures; Step 3.3: Establish numerical simulation models of mechanical motion at different temperatures using the calibrated constitutive model parameters, and obtain numerical simulation data of mechanical motion at different temperatures through numerical simulation. Step 3.4: If the error between the experimental data and numerical simulation data of different temperatures is within 20%, save the constitutive model parameters and numerical simulation models of different temperatures; otherwise, recalibrate the constitutive model parameters and return to step 3.3.

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