闭孔泡沫铝低速冲击防护的临界条件与优化设计  

CRITICAL CONDITIONS AND OPTIMAL DESIGN OF CLOSED-CELLED ALUMINUM FOAM PROTECTION UNDER LOW VELOCITY IMPACT

作　　者：李斌潮[1] 赵桂平[2] 卢天健[1] 

机构地区：[1]西安交通大学强度与振动教育部重点实验室,西安710049 [2]西安交通大学航天航空学院,西安710049

出　　处：《固体力学学报》2011年第4期325-338,共14页Chinese Journal of Solid Mechanics

基　　金：国家重大基础研究计划项目(2006CB601202);国家"111计划"引智计划项目(B06024);国家自然科学基金项目(10632060;10825210)资助

摘　　要：建立了高孔隙率闭孔泡沫铝抗低速撞击的分析模型,通过落重冲击试验验证了模型预测的准确性;采用所建立的模型,计算了闭孔泡沫铝作为大质量结构抗低速冲击构件的临界冲击速度,研究了不同冲击条件下结构响应的最小加速度和临界加速度.结果表明,闭孔泡沫铝适合作为大质量结构的低速冲击防护材料:当撞击速度低于临界冲击速度时,泡沫铝的作用应力不会超过其平台压缩应力,具有高孔隙率的泡沫铝甚至可使冲击响应加速度大幅降低,具有优良的防护效果;当撞击速度超过相应条件下的临界速度时,由于泡沫铝压缩密实阶段的应力增强作用,不仅使其作用应力迅速增大(为平台应力的5-15倍),而且使冲击响应加速度迅速增加甚至超过1000g,从而对结构的安全防护构成威胁.最后,讨论了冲击质量比、泡沫铝孔隙率、泡沫几何尺寸等冲击参数对临界冲击速度和冲击响应加速度的影响.A one-dimensional collision model for a large-mass structure protected by high porosity, close-celled aluminum foam subjected to low velocity impact is established and validated with drop hammer tests. Based on the proposed model, the concept of critical impact velocity is introduced, which is dependent upon the mass ratio of the collision system as well as foam porosity. Both the minimum acceleration and critical acceleration of the protected structure are obtained under different impact conditions. It is demon- strated that closed-celled aluminum foams are suitable for protecting large-mass structures subjected to low velocity impact. When the initial impact velocity is lower than the critical one, the stress imposed by the foam on the structure will not exceed the plateau stress of the foam,with the corresponding acceleration of the structure significantly reduced if the foam porosity is relatively high. On the other hand, when the ini- tial velocity exceeds the critical one,due to foam densification,the imposed stress increases sharply （about 5-15 times of foam plateau stress） ：correspondingly, the acceleration of the structure increases rapidly （even up to 1000g）. The influence of impact mass ratio, porosity and geometrical dimensions of foam protection on the critical velocity and acceleration is systematically explored.

关 键 词：临界冲击速度 响应加速度 低速冲击 防护 闭孔泡沫铝 优化设计 

分 类 号：TB383.4[一般工业技术—材料科学与工程]