基于虚拟裂缝黏聚应力分布,采用解析法与权函数法,对高温后混凝土断裂全过程的裂缝扩展阻力曲线进行求解.试验采用楔入劈拉法,设置20～600℃共10组温度.混凝土断裂全过程划分为四个部分,裂缝黏聚应力按照Petersson及CEB-FIP Model 1990...基于虚拟裂缝黏聚应力分布,采用解析法与权函数法,对高温后混凝土断裂全过程的裂缝扩展阻力曲线进行求解.试验采用楔入劈拉法,设置20～600℃共10组温度.混凝土断裂全过程划分为四个部分,裂缝黏聚应力按照Petersson及CEB-FIP Model 1990两类双线性软化本构曲线分布.结果表明：断裂韧度阻力曲线随裂缝扩展长度的增加而增长,但随温度的上升呈下降趋势;解析法与权函数法计算结果吻合较好;软化本构曲线对断裂韧度阻力曲线的形状有明显影响.展开更多
By using an instrumented impact pendulum, the force versus time curves of 7075-T651 aluminum welds were obtained from standard Charpy-V samples. Considering the force-time curves and constant impact velocity, the frac...By using an instrumented impact pendulum, the force versus time curves of 7075-T651 aluminum welds were obtained from standard Charpy-V samples. Considering the force-time curves and constant impact velocity, the fracture energies for different zones were quantified. A fracture energy improvement for the HAZ(33.6 J) was observed in comparison with the weld metal(7.88 J), and base metal(5.37 J and 7.37 J for longitudinal and transverse directions, respectively). This toughness increment was attributed to the microstructural transformation caused by the thermodynamic instability of η′ precipitates during the welding. Fracture energy for weld metal was higher than that for base metal, probably due to pores created during solidification. Regarding the dynamic yielding force obtained from the force-time curves, an approximation to the dynamic yield strength for weld, HAZ and base metal was determined. Fracture surfaces revealed an intergranular failure for base metal in longitudinal direction, whereas a predominately brittle failure(cleavage) with some insights of ductile characteristics was observed for the transverse direction. In contrast, a ductile failure was observed for weld metal and HAZ.展开更多
文摘基于虚拟裂缝黏聚应力分布,采用解析法与权函数法,对高温后混凝土断裂全过程的裂缝扩展阻力曲线进行求解.试验采用楔入劈拉法,设置20～600℃共10组温度.混凝土断裂全过程划分为四个部分,裂缝黏聚应力按照Petersson及CEB-FIP Model 1990两类双线性软化本构曲线分布.结果表明：断裂韧度阻力曲线随裂缝扩展长度的增加而增长,但随温度的上升呈下降趋势;解析法与权函数法计算结果吻合较好;软化本构曲线对断裂韧度阻力曲线的形状有明显影响.
基金CONACy T (project CB 177834)SIP-IPN for the funds given to conduct this research
文摘By using an instrumented impact pendulum, the force versus time curves of 7075-T651 aluminum welds were obtained from standard Charpy-V samples. Considering the force-time curves and constant impact velocity, the fracture energies for different zones were quantified. A fracture energy improvement for the HAZ(33.6 J) was observed in comparison with the weld metal(7.88 J), and base metal(5.37 J and 7.37 J for longitudinal and transverse directions, respectively). This toughness increment was attributed to the microstructural transformation caused by the thermodynamic instability of η′ precipitates during the welding. Fracture energy for weld metal was higher than that for base metal, probably due to pores created during solidification. Regarding the dynamic yielding force obtained from the force-time curves, an approximation to the dynamic yield strength for weld, HAZ and base metal was determined. Fracture surfaces revealed an intergranular failure for base metal in longitudinal direction, whereas a predominately brittle failure(cleavage) with some insights of ductile characteristics was observed for the transverse direction. In contrast, a ductile failure was observed for weld metal and HAZ.
