摘要
对混凝土、岩石类脆性材料的层裂实验进行了有限元模拟,研究了应力波在此类材料中传播的衰减规律,包括两类机制:弹性波因大尺寸试样的几何弥散产生的小幅度线性衰减、与应变率相关的黏塑性波因本构关系导致的指数衰减。在此基础上,提出了包含常数项的指数型应力波峰值拟合公式。建议采用可以忽略应力波衰减影响的细长形试样进行层裂实验。混凝土类脆性材料层裂破坏模拟结果显示,有限元模拟得到的层裂片厚度与一维应力波理论得到的结果非常吻合,验证了按一维应力波理论确定层裂强度的实验方法的有效性。通过对比3种不同入射波形下层裂片的形状和净拉应力波形,发现不对称的入射波形状更有利于实验获得平直的层裂断面和较准确的层裂强度。
Using finite element simulation, we investigated the spalling of sconcrete and rock,studied the attenuation mechanism governing the stress wave propagation through the specimen of brittle materials, and found two kinds of mechanisms： the small amplitude linear attenuation of the elastic wave due to the geometric dispersion of the large size specimen, and the exponential decay of the viscoplastic wave associated with the strain rate due to the constitutive rela-tion. Based on this,we proposed a peak fitting formula of exponential type stress wave with a con-stant term. It is suggested that we should choose a slender specimen in the spalling test ／n which the attenuation of the stress wave can be ignored. In addition,we studied the spalling damage of concrete and rock. The scab thickness obtained from the finite element method agrees well wsional stress wave theory, verifying that the method for determining the spalling strength by one-dimensional stress wave theory is effective. By comparing the scab shape and the tensile stress wave of the brittle material loading by three kinds of the incident wave,we proved that iobtain a flatter spalling cross-section and more precise strength by using an asymmetric incident wave.
出处
《爆炸与冲击》
EI
CAS
CSCD
北大核心
2017年第4期705-711,共7页
Explosion and Shock Waves
关键词
脆性材料
应力波
衰减规律
层裂
brittle material
stress wave
attenuation law
spalling
