To investigate the bedding influence on coal mechanical behaviour in underground environments such as coal or rock burst, simulations of dynamic SHPB tests of pre-stressed coal specimens with different bedding angles ...To investigate the bedding influence on coal mechanical behaviour in underground environments such as coal or rock burst, simulations of dynamic SHPB tests of pre-stressed coal specimens with different bedding angles were carried out using a particle flow code 2-dimensional(PFC2D). Three impact velocities of 4, 8 and 12 m/s were selected to study dynamic behaviours of coal containing bedding planes under different dynamic loads. The simulation results showed that the existence of bedding planes leads to the degradation of the mechanical properties and their weakening effect significantly depends on the angle h between the bedding planes and load direction. With h increaseing from 0° to 90°, the strength first decreased and subsequently increased and specimens became most vulnerable when h was 30° or 45°.Five failure modes were observed in the specimens in the context of macro-cracks. Furthermore, energy characteristics combined with ultimate failure patterns revealed that maximum accumulated energy and failure intensity have a positive relation with the strength of specimen. When bedding planes were parallel or perpendicular to loading direction, specimens absorbed more energy and experienced more violent failure with increased number of cracks. In contrast, bedding planes with h of 30° or 45° reduced the specimens' ability of storing strain energy to the lowest with fewer cracks observed after failure.展开更多
风力机叶片的全尺寸检测是对叶片质量和安全性进行评估的重要手段,而叶片的静载荷试验是分析叶片结构稳定性的重要基础。对100 k W风力机叶片进行了静载荷试验,对试验方法和试验条件进行了详细介绍。采用不测力法,分别从最大摆振、最小...风力机叶片的全尺寸检测是对叶片质量和安全性进行评估的重要手段,而叶片的静载荷试验是分析叶片结构稳定性的重要基础。对100 k W风力机叶片进行了静载荷试验,对试验方法和试验条件进行了详细介绍。采用不测力法,分别从最大摆振、最小摆振、最大挥舞、最小挥舞4个方向施加载荷。基于测得的叶片静载荷数据,分析了叶片在载荷作用下的刚度及应变等性能,并通过失效试验对叶片的安全性能进行了评价。评价表明,叶片具有较大的安全裕量。展开更多
基金the Chinese Scholarship Council (No. 201706370022) for the financial support to the joint Ph.D. programme at the University of Wollongong,Australia
文摘To investigate the bedding influence on coal mechanical behaviour in underground environments such as coal or rock burst, simulations of dynamic SHPB tests of pre-stressed coal specimens with different bedding angles were carried out using a particle flow code 2-dimensional(PFC2D). Three impact velocities of 4, 8 and 12 m/s were selected to study dynamic behaviours of coal containing bedding planes under different dynamic loads. The simulation results showed that the existence of bedding planes leads to the degradation of the mechanical properties and their weakening effect significantly depends on the angle h between the bedding planes and load direction. With h increaseing from 0° to 90°, the strength first decreased and subsequently increased and specimens became most vulnerable when h was 30° or 45°.Five failure modes were observed in the specimens in the context of macro-cracks. Furthermore, energy characteristics combined with ultimate failure patterns revealed that maximum accumulated energy and failure intensity have a positive relation with the strength of specimen. When bedding planes were parallel or perpendicular to loading direction, specimens absorbed more energy and experienced more violent failure with increased number of cracks. In contrast, bedding planes with h of 30° or 45° reduced the specimens' ability of storing strain energy to the lowest with fewer cracks observed after failure.
文摘风力机叶片的全尺寸检测是对叶片质量和安全性进行评估的重要手段,而叶片的静载荷试验是分析叶片结构稳定性的重要基础。对100 k W风力机叶片进行了静载荷试验,对试验方法和试验条件进行了详细介绍。采用不测力法,分别从最大摆振、最小摆振、最大挥舞、最小挥舞4个方向施加载荷。基于测得的叶片静载荷数据,分析了叶片在载荷作用下的刚度及应变等性能,并通过失效试验对叶片的安全性能进行了评价。评价表明,叶片具有较大的安全裕量。
