In the present investigation, by putting the isogeometric finite element methodology to use, the nonlinear flexural response of composite rectangular microplates having functionally graded (FG) porosity is predicted incorporating couple stress type of small scale effect. To accomplish this analysis, a non-uniform kind of rational B-spline functions are employed for an accurate geometrical description of cutouts with various shapes located at the center of microplates. The modified couple stress continuum elasticity is implemented within the framework of a new quasi-three-dimensional (quasi-3D) plate theory incorporating normal deflections with only four variables. By refining the power-law function, the porosity dependency in conjunction with the material gradient are taken into consideration in a simultaneous scheme. The couple stress-based nonlinear flexural curves are achieved numerically based upon a parametrical study. It is demonstrated that for a larger plate deflection, the role of couple stress type of small scale effect on the nonlinear bending curves of porous FG composite microplates is highlighted. It is seen that the gap between nonlinear flexural responses associated with different through-thickness porosity distribution schemes is somehow higher by taking the couple stress effect into account. Also, it is observed that the existence of a cutout at the center of composite microplates makes a change in the slope of their nonlinear flexural curve.

在本研究中，通过使用等几何有限元方法，预测具有功能梯度 (FG) 孔隙率的复合矩形微板的非线性弯曲响应，并结合小尺度效应的耦合应力类型。为完成此分析，采用非均匀的有理 B 样条函数对位于微孔板中心的各种形状的切口进行精确的几何描述。修正的耦合应力连续弹性是在新的准三维（准 3D）板理论的框架内实现的，该理论结合了只有四个变量的法向挠度。通过细化幂律函数，在同步方案中考虑了孔隙度依赖性与材料梯度。基于参数研究以数值方式获得基于耦合应力的非线性弯曲曲线。结果表明，对于较大的板挠度，强调了小尺度效应的耦合应力类型对多孔 FG 复合微板的非线性弯曲曲线的作用。可以看出，通过考虑耦合应力效应，与不同的全厚度孔隙度分布方案相关的非线性弯曲响应之间的差距在某种程度上更高。此外，还观察到复合微板中心切口的存在使其非线性弯曲曲线的斜率发生变化。强调了耦合应力类型的小尺度效应对多孔 FG 复合微孔板的非线性弯曲曲线的作用。可以看出，通过考虑耦合应力效应，与不同的全厚度孔隙度分布方案相关的非线性弯曲响应之间的差距在某种程度上更高。此外，还观察到复合微板中心切口的存在使其非线性弯曲曲线的斜率发生变化。强调了耦合应力类型的小尺度效应对多孔 FG 复合微孔板的非线性弯曲曲线的作用。可以看出，通过考虑耦合应力效应，与不同的全厚度孔隙度分布方案相关的非线性弯曲响应之间的差距在某种程度上更高。此外，还观察到复合微板中心切口的存在使其非线性弯曲曲线的斜率发生变化。