为深入研究炸高对聚能切割索(Flexible Linear Shaped Charge,FLSC)切割能力的影响,开展了聚能切割索在0~5mm炸高条件下切割20mm厚有机玻璃板的爆炸切割试验;建立了一种有机玻璃有限元模型及切割索炸药模型,数值模拟研究了0mm和5mm炸高...为深入研究炸高对聚能切割索(Flexible Linear Shaped Charge,FLSC)切割能力的影响,开展了聚能切割索在0~5mm炸高条件下切割20mm厚有机玻璃板的爆炸切割试验;建立了一种有机玻璃有限元模型及切割索炸药模型,数值模拟研究了0mm和5mm炸高情况下切割索爆破侵彻过程,并与试验结果进行对比。结果表明:该聚能切割索射流的汇聚过程较短,最佳炸高为0mm。随着炸高增加,侵彻能力逐渐减弱,层裂宽度逐渐增加,断面平整度降低;该切割索在0~4mm炸高下均能稳定切割20mm厚有机玻璃材料,5mm炸高情况下射流发散,无法形成有效切割能力;并且,仿真分析与试验结果一致性较高,最大误差为6%。展开更多
Floodwater and debris flow caused by glacial lake burst is an important land process and a serious mountain disaster in glacial area of Xizang (Tibet) Autonomous Region, and the overflow burst is mainly caused by glac...Floodwater and debris flow caused by glacial lake burst is an important land process and a serious mountain disaster in glacial area of Xizang (Tibet) Autonomous Region, and the overflow burst is mainly caused by glacial landslide falling into moraine lake. On the premise that moraine lake is full, instantaneous burst in part of the lake bank happens, as flow velocity at burst mouth caused by overflow head is higher than threshold flow velocity of glacial till. Under some supposes, d(90) and d(10) of the glacial till in the hank were used as the threshold sizes of coarse and fine grains respectively. Thus, the formula of calculating threshold flow velocity of uniform sand was simplified, and threshold flow velocity of glacial till was calculated with the formula. Then, with synthesis formula calculating flow velocity of instantaneous part burst, flow velocity at overflow burst mouth was calculated, and calculation formula of critical height (H(0)) of overflow head was derived. Overflow head was caused by volume and surge of glacial landslide falling into moraine lake, calculation formulas of ascendant height (H(1)) of lake water surface and surge height (H(2)) on burst mouth caused by glacial landslide falling into moraine lake were derived. To sum up, critical hydrologic conditions of moraine lake burst with overflow form are: the burst is inevitable as H(1) > H(0); the burst is possible as H(1) < H(0) and (H(1)+H(2)) > H(0); the burst is impossible as (H(1)+H(2)) < H(0). In the factors influencing the burst critical conditions, it is advantageous for the burst that scale of the lake is 10(5)m(2) range; terminal glacial till is more fine and is even more uniform; the width of overflow mouth is even smaller than the length of the bank; the landslide has large scale and steep slip surface; and glacial end is close to the lake. With burst of Guangxiecuo Lake in Midui Valley of the Polongzangbu River in Xizang as an example, the burst critical conditions were tested.展开更多
文摘为深入研究炸高对聚能切割索(Flexible Linear Shaped Charge,FLSC)切割能力的影响,开展了聚能切割索在0~5mm炸高条件下切割20mm厚有机玻璃板的爆炸切割试验;建立了一种有机玻璃有限元模型及切割索炸药模型,数值模拟研究了0mm和5mm炸高情况下切割索爆破侵彻过程,并与试验结果进行对比。结果表明:该聚能切割索射流的汇聚过程较短,最佳炸高为0mm。随着炸高增加,侵彻能力逐渐减弱,层裂宽度逐渐增加,断面平整度降低;该切割索在0~4mm炸高下均能稳定切割20mm厚有机玻璃材料,5mm炸高情况下射流发散,无法形成有效切割能力;并且,仿真分析与试验结果一致性较高,最大误差为6%。
基金Foundation term: Under the auspices of the Knowledge Innovation Program of Chinese Academy of Sciences(KZCX2-306)
文摘Floodwater and debris flow caused by glacial lake burst is an important land process and a serious mountain disaster in glacial area of Xizang (Tibet) Autonomous Region, and the overflow burst is mainly caused by glacial landslide falling into moraine lake. On the premise that moraine lake is full, instantaneous burst in part of the lake bank happens, as flow velocity at burst mouth caused by overflow head is higher than threshold flow velocity of glacial till. Under some supposes, d(90) and d(10) of the glacial till in the hank were used as the threshold sizes of coarse and fine grains respectively. Thus, the formula of calculating threshold flow velocity of uniform sand was simplified, and threshold flow velocity of glacial till was calculated with the formula. Then, with synthesis formula calculating flow velocity of instantaneous part burst, flow velocity at overflow burst mouth was calculated, and calculation formula of critical height (H(0)) of overflow head was derived. Overflow head was caused by volume and surge of glacial landslide falling into moraine lake, calculation formulas of ascendant height (H(1)) of lake water surface and surge height (H(2)) on burst mouth caused by glacial landslide falling into moraine lake were derived. To sum up, critical hydrologic conditions of moraine lake burst with overflow form are: the burst is inevitable as H(1) > H(0); the burst is possible as H(1) < H(0) and (H(1)+H(2)) > H(0); the burst is impossible as (H(1)+H(2)) < H(0). In the factors influencing the burst critical conditions, it is advantageous for the burst that scale of the lake is 10(5)m(2) range; terminal glacial till is more fine and is even more uniform; the width of overflow mouth is even smaller than the length of the bank; the landslide has large scale and steep slip surface; and glacial end is close to the lake. With burst of Guangxiecuo Lake in Midui Valley of the Polongzangbu River in Xizang as an example, the burst critical conditions were tested.
