共查询到14条相似文献,搜索用时 125 毫秒
1.
2.
根据叠加原理将含有椭圆形非穿透分层的层板在横向载荷作用下的受力状态进行分解,从而将分层问题归结为在分层表面上的附加剪切载荷作用下层板附加位移与附加应力的分析,并据此建立了一个仅包含分层区的力学模型。进而在层板分层区中切取平行于坐标平面的切片,将切片视为含分层的层合梁,其位移模态以相应层合梁的附加位移模态来表示。这样,可构造层板分层区内满足位移边界条件的位移场。最后,应用最小势能原理确定位移幅值的闭合解。计算结果表明,挠度幅值远远大于中面位移幅值,且与由双三角级数能量解法所得挠度幅值吻合很好。 相似文献
3.
根据叠加原理将含有矩形内部分层的层板在横向载荷作用下的受力状态进行分解, 从而 将分层问题归结为在分层表面上的附加剪切载荷作用下层板附加位移与附加应力的分析, 并据此 建立了一个仅包含分层区的力学模型。进而在层板分层区中切取平行于边界的切片, 将切片视为 含分层的层合梁, 其位移模态以相应层合梁的附加位移模态来表示。这样, 可构造层板分层区内满 足位移边界条件的位移场。最后, 应用最小势能原理确定位移幅值的闭合解。计算结果表明, 挠度 幅值远远大于中面位移幅值, 且与由双三角级数能量解法所得挠度幅值吻合很好。 相似文献
4.
5.
根据叠加原理将横向载荷作用下的含有非对称矩形内部分层的层板进行状态分解,从而将分层问题归结为分层表面上的附加剪切载荷作用下层板附加位移与附加应力的分析,并据此建立一个仅包含分层区的简单的力学模型。进而在分层区中切取平行于边界的无限小的切片,将切片视为含分层的层合梁,其位移模态以相应的层合梁的附加位移模态表示。在此基础上构造层板分层区内满足位移边界条件的位移模态,最后用最小势能原理确定位移幅值的闭合解并且分析了分层区的应力场和能量释放率。 相似文献
6.
为了克服经典层合板理论的缺点,提高层间应力的计算精度,提出了受分布载荷层合板应力分析的一般理论。首先根据叠加原理将层合板受力状态分解成对称和反对称状态,然后用正交完备的傅立叶级数和勒让德级数构造这两种受力状态中每一铺层与层间胶层的位移场,并应用广义势能原理确定位移场中的待定系数,从而确定层合板的位移场和应力场。另外,胶层被视为各向同性材料,并且与其它材料层具有相似的力学特性,即具有有限厚度、有限弹性常数。计算结果显示,这种解法的收敛性非常好,根据物理方程与根据平衡方程得到的层合板横向剪应力及横向正应力分布非常一致。 相似文献
7.
本文将非线性的接触问题线性化,即假设已知带可调参数的接触区载荷分布模态以及接触区宽度,再反求圆柱压头的半径。首先根据叠加原理将受力状态分解成对称和反对称状态,然后用正交完备的三角级数和勒让德级数构造这两种受力状态的位移场,并应用最小势能原理确定位移场中的待定系数,从而确定层合梁的位移场和应力场。载荷分布模态中的可调参数可根据接触区表面的位移协调条件确定,从而求得圆柱压头的半径。最后,由于在给定接触区的条件下压头曲率与压头合力成正比,故可以得到压头曲率在不同的接触区下随载荷变化的直线族。根据这些直线族,可以由已知的压头曲率和外载荷确定接触区尺寸。计算结果显示,这种解法的收敛性非常好。根据物理方程与根据平衡方程得到的层合梁剪应力分布的一致性非常好。而且,在远离接触区处的应力分布同经典层合梁理论结果的一致性也非常好。 相似文献
8.
9.
10.
11.
An analytical solution for predicting delamination buckling and growth of a thin fiber reinforced-plastic (FRP) layer in laminated wood beams under bending is presented. Based on a strength-of-materials approach, displacement functions for a delaminated beam under four-point bending are derived. Using force and displacement compatibility conditions, an explicit form relating the applied transverse load with the delamination buckling load is established. An explicit form of the strain-energy release rate is presented to study the delamination growth in beams under bending. The analytical solution is evaluated using experimental data for glued-laminated timber (glulam) beams reinforced with a thin fiber-reinforced plastic composite on the compression face. The delamination growth in bending is shown to behave differently to that of the in-plane loading case. 相似文献
12.
A “mutual integral” approach is used to calculate the mixed-mode stress intensity factors for a free-edge delamination crack
in a laminate under tensile loading conditions. This “mutual integral” approach, for generalized plane strain conditions,
is based on the application of the path-independent J integral to a linear combination of three solutions: one, the problem
of the laminate to be solved using the quasi 3-D finite element method, the second, an “auxiliary” solution with a known asymptotic
singular solution, and the third, the particular solution due to the out-of-plane loading. A comparison with the exact solutions
is made to determine the accuracy and efficiency of this numerical method. With this “mutual integral” approach, it was found
that the calculated mixed-mode stress intensity factors of the free-edge delamination crack remain relatively constant as
the crack propagates into the laminate. It was also found that the fracture criterion based on the mixed-mode stress intensity
factors is more consistent with the experimental observations than the criterion based on the total energy release rate, and
hence demonstrates the importance of the ability to calculate each individual component of the stress intensity factors. Furthermore,
it was found that the fracture toughness measurements from double cantilever beam specimens can be used directly to predict
the onset of delamination crack growth between two dissimilar laminae. Using these fracture toughness measurements from the
double cantilever beam specimens, some examples are given to show that the fracture criterion based on the mixed-mode stress
intensity factors can accurately predict the failure load for various laminates under tensile loading conditions. 相似文献
13.