GCr15弹丸冲击不同厚度GH4169板的变形与破坏模式试验研究

Tests for deformation and failure modes of GH4169 plates with different thickness under GCr15 projectile impact

为理解航空发动机包容机匣用镍基高温合金GH4169遭受高速冲击载荷时的动态力学特性,采用GCr15硬质合金弹丸,利用一级空气炮试验装置对不同厚度(2 mm、3 mm、5 mm、6 mm)的GH4169靶板进行了弹丸速度从96.7~314.2 m/s的弹道冲击试验,对冲击载荷作用下靶板的变形、破坏模式和失效机理进行了系统的试验研究。结果表明:在试验冲击速度范围之内,随着靶板厚度的增加,靶板的变形模式逐渐由拉伸与弯曲主导的蝶形变形转变为局部的剪切变形;同时靶板的破坏模式由花瓣形损伤与冲塞共存模式向单一剪切冲塞模式转变;随着冲击速度的增加,靶板对弹丸动能的吸收能量是逐渐增加的,但在临界穿透速度时出现一个拐点,使得靶板被击穿后吸收能能量的增速变缓,表明靶板被穿透破坏后降低其的吸能能力;当冲击速度为临界穿透速度时靶板变形挠度达到最大值;冲击后靶板的花瓣裂纹数量与弹体速度呈线性关系。当入射速度为284 m/s时,与试验结果比较,修正后R-I公式预测弹丸剩余速度比未修正的结果精度提高7.01%。

Here,to understand dynamic mechanical characteristics of nickel base superalloy GH4169 for aeroengine casing under high-speed impact load,GCr15 cemented carbide projectiles and one-stage air gun were adopted to conduct ballistic impact tests on GH4169 target plates with different thicknesses of 2 mm,3 mm,5 mm and 6 mm within the projectile velocity range of 96.7-314.2 m/s.The target plates’deformation,failure mode and failure mechanism under impact load were systematically studied.The results showed that within the range of impact velocity,with increase in target plate thickness,the deformation mode of target plate gradually changes from butterfly deformation dominated by tension and bending to local shear deformation;its failure mode changes from coexistence pattern of petal damage and tamponade to single shear tamponade one;with increase in impact velocity,the projectile kinetic energy absorbed by target plate increases gradually,but an inflection point appears at the critical penetration velocity to slow down the growth rate of the absorbed energy after target plate is broken down,so its energy absorption capacity drops after its being broken down;when the impact velocity is the critical penetration velocity,the deformation deflection of target plate reaches the maximum;the number of petal cracks on target plate after impact is linearly related to projectile velocity;when the incident velocity is 284 m/s,compared with the test results,the accuracy of the corrected R-I formula to predict projectile residual velocity is 7.01%higher than that of its uncorrected results.