TNT埋爆载荷下700 MPa高强韧钢变形行为及仿真分析

Deformation behavior and simulation of 700 MPa steel subjected to TNT buried explosion load

以自主研发的新型高强韧700 MPa防爆钢(BR700钢)为研究对象,结合LS-DYNA模拟计算软件和正交试验设计对BR700钢抗爆轰过程进行研究。根据测得的准静态及动态拉伸力学性能,拟合出了BR700防爆钢的Johnson-Cook本构方程。通过实爆试验,研究了20 mm厚钢板在8 kg TNT埋爆载荷下的抗爆轰变形行为。建立了相关仿真模型,使用LS-DYNA模拟计算软件分析了其变形量、应力应变分布情况以及超压。在确保仿真模型准确的情况下,结合有限元分析以及正交试验设计,以钢板的变形量D为评定指标,通过极差分析计算了材料屈服强度A、应变硬化模量B、应变硬化指数n、应变速率常数C和失效应变FS等因素对抗爆轰性能影响规律。结果表明,在不考虑工装偏移的条件下,8 kg TNT埋爆载荷下钢的抗爆轰变形模拟计算结果可以准确地反映BR700钢的抗爆轰变形行为。模拟结果与实际爆炸后钢板变形量误差仅为7.7%。且根据模拟结果的超压分析,钢板因其良好的塑韧性起到了较好的吸能作用,有效削弱了爆炸冲击波的破坏。根据正交试验模拟结果,对爆炸后钢板变形量D而言,材料屈服强度A值影响程度最高,其次是应变硬化指数n值。材料强度提升可以大幅减小爆炸变形量,可以有效降低爆炸冲击对车辆和乘员的伤害。同时通过1100 MPa钢板爆炸试验验证了强度对抗爆轰变形的影响。

A new type of 700 MPa explosion-proof steel(BR700)developed by ourselves was taken as the research object,and the blast resistence process of BR700 steel was studied by simulation and orthogonal experimental design.According to the measured quasi-static and dynamic tensile properties,the Johnson-Cook constitutive equation of BR700 explosion-proof steel was fitted.The deformation behavior of 20 mm thick steel plate under 8 kg TNT buried blast load was studied by detonation test.A simulation model was established,and LS-DYNA simulation software was used to analyze the deformation,stress-strain distribution and overpressure.Under the condition of ensuring the accuracy of simulation model,combined with finite element analysis and orthogonal experimental design.Based on the evaluation indexes of deformation D of steel plate,the rule of the parameters affecting on the blast resistence were calculated by using range analysis,such as material yield strength A,strain hardening constant B,strain hardening index n,strain rate constant C and failure strain FS.The results show that the simulation results of deformation of BR700 steel under 8 kg TNT buried blast load can accurately reflect the deformation behavior of BR700 steel without considering the offset of the tool.The error between the simulated results and the actual steel plate deformation is only 7.7%.According to the overpressure analysis of the simulation results,the steel plate has a good energy absorption effect because of its good plastic toughness,which effectively weakens the damage of the explosion shock wave.According to the orthogonal experimental simulation results,the yield strength A of the material has the highest influence on the deformation D of the steel plate after explosion,followed by the strain hardening index n.The increase of material strength can greatly reduce the amount of explosion deformation and effectively reduce the damage of the explosion impact on the vehicle and occupants.At the same time,the effect of strength on anti-detonation deformation was verified by 1100 MPa steel plate explosion experiment.