弹性平面问题超奇异边界积分方程的近似列式与数值求解

1　Introduction　Theformulationofboundaryvalue problemsintermsofhypersingularboundaryintegralequations(HBIE)isgainingincreasinginterestinrecentyearslargelyowingtothephysicalandengineeringrequire ments[1 8] .Theseequationsarecoupled quiteoftenwiththesingularboundaryintegralsinthesenseofCauchyprincipalvalues (CPV) .Thereliablenumeri caltreatmentofHBIEseemsstilltobeproblematic .Muchefforthasbeendevotedtothedevelopmentofvarioustypesofboundaryelementsintermsofspecialinterpolationsandcollocatio…     

Finite element simulation of stress intensity factors in elastic-plastic crack growth

INTRODUCTION The finite element method (FEM) has been widely employed for solving linear elastic and elas-tic-plastic fracture problems. The evaluation of stress intensity factors in 2D geometries by FEM is a tech-nique widely used for non-standard crack configura-tions. Basically, there are two groups of estimation methods, those based on field extrapolation near the crack tip (Chan et al., 1970; Shih et al., 1976) and those using the energy release when the crack propagates. However…     

Numerical simulation of mechanical behaviors of degradable porous bioceramics with cracks

Hydroxyapatite bioceramics is simulated by using finite element method (FEM).The influences of porosity,hole shape,angle of crack and other parameters on the ceramics are analyzed.The results show that with the increase of the angle between crack and horizontal direction,the stress intensity factor KⅠdecreases gradually,but stress intensity factor K II increases at first and then it decreases.The value of K Ⅱ reaches maximum when the angle between crack and horizontal direction is 45°.KⅠ and K Ⅱ rise with the increase of porosity,and they are almost the same for the circular and hexagonal holes.For elliptical holes,KⅠand KⅡreach maximum when the long axis of ellipse is perpendicular to the loading direction and they reach minimum when the same axis is parallel to the loading direction.Moreover,with the increase of the angle between the long axis and loading direction,KⅠ and KⅡ increase gradually.