Research On Creep Strength And Life For Ultralight Lattice Truss Sandwich Plate Structure

Lattice truss sandwich plate structure material, with the feature of light weight, highstrength, good multi-functional comprehensive application, is widely recognised as a kind ofnew lightweight material whose application prospect is very broad. This paper studies thepyramid and X type lattice material on creep strength and life by finite element method,which will provide some theoretical guidance for the future application in project. The mainresearch contents and conclusions of this paper are as follows:(1) This paper designs a higher-bearing capacity X type lattice material with rectangularnode, and studies a group of the same relative density pyramid and X type lattice material oncreep strength and life, finding that the advantage of X type lattice material’s incipient andcreep bearing capacity is very obvious for the strengthening function of rectangular X node,while the difference of their creep life is not big. The change of single geometric factors willincrease the creep strength and life when it increases the relative density. And it found thefunction between two lattice materials’ incipient integral strain, integral creep rate, creep lifeand the load.(2) This paper deduces the pyramid and X type lattice core’s calculation formula ofrelative density. Then it found the effect of these geometric factors, plate thickness T,stamping angle α, cut angle β, beam length L, beam width w, beam thickness d, on the corerelative density, the cell overall performance and creep life. And it found the function betweentwo lattice materials’ incipient integral strain, integral creep rate, creep life and thesegeometric factors.(3) This paper analyzes the effect of the different relative density on overall and localperformance, and found that these two kinds of lattice materials can not directly get thefunction of overall performance and relative density like foam materials. Then the paper getsthe six variables functions of the integral creep rate, creep life and the geometry factors and load. Then this paper gives the design criteria of the pyramid and X type lattice material fromtwo sides of the load and the geometric structure.(4) Finally, the paper discusses the creep performance of the non-ideal multi-cellspyramid and X type lattice material models which have local defects, and finds the cell localfailure effect on the overall properties of the two kinds of lattice materials. The paperproposes the concept of failure cumulative effect, and deduces the lattice materials’calculation formula of the failure cumulative effect divisor. And it is proved the calculationformula is right through comparison of analytic and numerical results.