厚壁胞体的孔结构形态对其接触强度影响的研究

Study on Influence of Cell-structures on Contact Strength of Thick-walled Cellular Materials

选用H59黄铜为材料,制备了具有不同微孔结构的圆柱体单孔试样,采用型号为YE-600的液压式压力试验机对试样进行压缩试验,探讨了孔隙率、微孔形状以及承载方向对厚壁胞体多孔材料接触强度的影响。研究表明:厚壁胞体多孔材料的接触强度不仅随着孔隙率的增大而降低,而且与孔结构形态密切相关;正六边形孔胞体的接触强度大于圆形孔胞体,且其对边受力情况的失效力大于对角受力情况;裂纹源均产生在微孔边缘且离初始接触点最近的地方,并且裂纹沿着平行于外力的方向进行扩展;该胞体材料的接触失效主要由最大拉伸主应力引起。

Materials of H59 brass were chosen for the preparation of cylindrical specimens which contained single pore with different structures,and YE-600 hydraulic pressure testing machine was used for compression tests on these specimens.The influences of the porosity,the shape of the pore and the load-bearing direction on the contact strength of the materials were discussed.Research results show that： the increase of porosity leads to the decrease of contact strength of the material,and its contact strength is markedly effected by the pore-structures.The contact strength of the material with regular hexagon pore is superior to the material with round hole,and the contact strength of the load to-edge is higher than that of the load in diagonal.Cracks are generated in the edge of micropore which is the nearest away from the initial point of contact and expandes along the direction which is parallel to the load.It is indicated by the contrast between experiments and finite element analysis that the contact failure of the thick-walled cellular materials is caused by the largest principal stretching stress.