To model the damage process of masonry walls under blast loading, a dynamic continuum damage material model is constructed for brick and mortar separately. The degradation of both the stiffness and strength are govern...To model the damage process of masonry walls under blast loading, a dynamic continuum damage material model is constructed for brick and mortar separately. The degradation of both the stiffness and strength are governed by a damage variable. By using the proposed material model, damage and fragmentation of a typical masonry wall under blast loading at different scaled distances is calculated. The hazard level of the masonry wall to blast loading is evaluated by analyzing the numerical results.展开更多
Thermal cracking occurs in the plastic packaging materials due to the presence of moisturized micro-cavities in the material.The moisture resident in the micro-cavities gives rise to the internal vapor pressure that d...Thermal cracking occurs in the plastic packaging materials due to the presence of moisturized micro-cavities in the material.The moisture resident in the micro-cavities gives rise to the internal vapor pressure that drives the thermal expansion of micro-cavities as temperature rises.The plastic packaging materials are considered a class of thermo-hyperelastic materials,thus allowing the micro-cavities to thermally expand to the substantial extent before the cracking failure.The micro-cavities can be moisture-abundant(i.e.,wet) or substantially dry when cracking occurs.Cracking appears to be almost certain in the presence of wet cavities.The possibility of cracking in dry cavities turns to be two-sided:when the initial volume fraction of the micro-cavities is relatively small,cracking cannot occur in the dry cavities regardless of the phase transition temperature;when the initial cavity volume fraction is relatively large,cracking tends to occur in the dry cavities especially when the phase transition temperature is large.Because of the two-sided cracking possibility,the dry-cavity cracking mode presents a scenario that might reveal the mechanism of popcorning-type cracking failure in plastic packaging materials.展开更多
文摘To model the damage process of masonry walls under blast loading, a dynamic continuum damage material model is constructed for brick and mortar separately. The degradation of both the stiffness and strength are governed by a damage variable. By using the proposed material model, damage and fragmentation of a typical masonry wall under blast loading at different scaled distances is calculated. The hazard level of the masonry wall to blast loading is evaluated by analyzing the numerical results.
基金supported by the National Natural Science Foundation of China (Grant No. 11172195)the Natural Science Foundation of Shanxi Province,China (Grant No. 2012011019-4)
文摘Thermal cracking occurs in the plastic packaging materials due to the presence of moisturized micro-cavities in the material.The moisture resident in the micro-cavities gives rise to the internal vapor pressure that drives the thermal expansion of micro-cavities as temperature rises.The plastic packaging materials are considered a class of thermo-hyperelastic materials,thus allowing the micro-cavities to thermally expand to the substantial extent before the cracking failure.The micro-cavities can be moisture-abundant(i.e.,wet) or substantially dry when cracking occurs.Cracking appears to be almost certain in the presence of wet cavities.The possibility of cracking in dry cavities turns to be two-sided:when the initial volume fraction of the micro-cavities is relatively small,cracking cannot occur in the dry cavities regardless of the phase transition temperature;when the initial cavity volume fraction is relatively large,cracking tends to occur in the dry cavities especially when the phase transition temperature is large.Because of the two-sided cracking possibility,the dry-cavity cracking mode presents a scenario that might reveal the mechanism of popcorning-type cracking failure in plastic packaging materials.
