Adopting the classical theory of hydrocodes,the constitutive relations of concretes are separated into an equation of state(EoS)which describes the volumetric behavior of concrete material and a strength model which d...Adopting the classical theory of hydrocodes,the constitutive relations of concretes are separated into an equation of state(EoS)which describes the volumetric behavior of concrete material and a strength model which depicts the shear properties of concrete.The experiments on the EoS of concrete is always challenging due to the technical difficulties and equipment limitations,especially for the specimen size effect on the EoS.Although some researchers investigate the shock properties of concretes by fly-plate impact tests,the specimens used in their tests are usually in one size.In this paper,the fly-plate impact tests on concrete specimens with different sizes are performed to investigate the size effect on the shock properties of concrete materials.The mechanical background of the size effect on the shock properties are revealed,which is related to the lateral rarefaction effect and the deviatoric stress produced in the specimen.According to the tests results,the modified EoS considering the size effect on the shock properties of concrete are proposed,which the bulk modulus of concrete is unpredicted by up to 20% if size effects are not accounted for.展开更多
PETN、RDX和造粒RDX可作为飞片雷管激发药。为了研究这3种激发药的燃烧性能,制备了不同配比的造粒RDX,并采用50 m L密闭爆发器测试了3种激发药定容条件下的燃烧速度和峰值压力。结果表明:相同点火条件下,PETN的燃烧速度大于RDX;相同质量...PETN、RDX和造粒RDX可作为飞片雷管激发药。为了研究这3种激发药的燃烧性能,制备了不同配比的造粒RDX,并采用50 m L密闭爆发器测试了3种激发药定容条件下的燃烧速度和峰值压力。结果表明:相同点火条件下,PETN的燃烧速度大于RDX;相同质量的RDX燃烧产生的峰值压力大于PETN;随着KClO_4质量分数的增加,造粒RDX的燃烧速度和峰值压力均呈现先增大后减小的趋势;当KClO_4质量分数为30%-40%时,造粒RDX燃烧性能最佳。展开更多
低温共烧陶瓷技术(Low Temperature Co-fired Ceramic LTCC)是近年来兴起的一种相当令人瞩目的多学科交叉的整合组件技术,广泛用于基板、封装及微波器件等领域。主要介绍当前广泛用于检测混合电路板、LTCC陶瓷基板、PCB裸板故障的飞针...低温共烧陶瓷技术(Low Temperature Co-fired Ceramic LTCC)是近年来兴起的一种相当令人瞩目的多学科交叉的整合组件技术,广泛用于基板、封装及微波器件等领域。主要介绍当前广泛用于检测混合电路板、LTCC陶瓷基板、PCB裸板故障的飞针测试设备在陶瓷基片测试中的工艺研究。展开更多
基金supported by the National Natural Science Foundation of China[Grant Nos.51938011 and 51908405]Australian Research Council。
文摘Adopting the classical theory of hydrocodes,the constitutive relations of concretes are separated into an equation of state(EoS)which describes the volumetric behavior of concrete material and a strength model which depicts the shear properties of concrete.The experiments on the EoS of concrete is always challenging due to the technical difficulties and equipment limitations,especially for the specimen size effect on the EoS.Although some researchers investigate the shock properties of concretes by fly-plate impact tests,the specimens used in their tests are usually in one size.In this paper,the fly-plate impact tests on concrete specimens with different sizes are performed to investigate the size effect on the shock properties of concrete materials.The mechanical background of the size effect on the shock properties are revealed,which is related to the lateral rarefaction effect and the deviatoric stress produced in the specimen.According to the tests results,the modified EoS considering the size effect on the shock properties of concrete are proposed,which the bulk modulus of concrete is unpredicted by up to 20% if size effects are not accounted for.
文摘PETN、RDX和造粒RDX可作为飞片雷管激发药。为了研究这3种激发药的燃烧性能,制备了不同配比的造粒RDX,并采用50 m L密闭爆发器测试了3种激发药定容条件下的燃烧速度和峰值压力。结果表明:相同点火条件下,PETN的燃烧速度大于RDX;相同质量的RDX燃烧产生的峰值压力大于PETN;随着KClO_4质量分数的增加,造粒RDX的燃烧速度和峰值压力均呈现先增大后减小的趋势;当KClO_4质量分数为30%-40%时,造粒RDX燃烧性能最佳。
文摘低温共烧陶瓷技术(Low Temperature Co-fired Ceramic LTCC)是近年来兴起的一种相当令人瞩目的多学科交叉的整合组件技术,广泛用于基板、封装及微波器件等领域。主要介绍当前广泛用于检测混合电路板、LTCC陶瓷基板、PCB裸板故障的飞针测试设备在陶瓷基片测试中的工艺研究。
