Abstract

Present investigation deals with the snap-through phenomenon in a thermally pre-buckled or post-buckled reinforced composites beam. Composite laminated beam is reinforced with graphene platelets (GPLs) where the weight fraction of GPLs may vary in each layer. The governing equations of the beam are obtained by means of the first order shear deformation beam theory and the von-Kármán type of kinematic assumptions. The conventional Ritz method with Chebyshev polynomials is used to discretize the governing equations and establish a set of non-linear equations dealing with the response of a beam under the action of thermal and mechanical loads. Furthermore, the case of uniform temperature elevation in the beam and uniform lateral pressure is considered. At first, the response of the beam under uniform temperature elevation is obtained. Depending on the magnitude of temperature rise, beam may remain flat or undergo thermal post-buckling. Using the displacement control strategy, the non-linear eigenvalue problem is solved. After that the response of the pre-buckled or post-buckled beam subjected to uniform lateral pressure in large deflection is evaluated. Due to the possibility of snap-through phenomenon, the cylindrical arch-length technique is employed. At first, two comparison studies are provided to assure the validity and efficiency of the developed formulation. After that, novel numerical results are given to discuss the effects of temperature change, weight fraction of GPLs, distribution pattern of GPLs and boundary conditions. It is shown that the limit loads of the snapping phenomenon and the intensity of the snap-through phenomenon are highly dependent to the mentioned factors.

摘要

目前的研究涉及在热预屈曲或后屈曲的增强复合材料梁中的卡扣现象。复合层压梁用石墨烯薄片（GPL）增强，其中GPL的重量分数在每一层中都可能不同。借助一阶剪切变形梁理论和von-Kármán类型的运动学假设获得梁的控制方程。使用具有Chebyshev多项式的常规Ritz方法离散化控制方程，并建立一组非线性方程，处理梁在热载荷和机械载荷作用下的响应。此外，考虑梁中温度升高均匀且侧向压力均匀的情况。首先，获得光束在均匀温度升高下的响应。根据温升的幅度，光束可能保持平坦或经历热后屈曲。使用位移控制策略，解决了非线性特征值问题。之后，评估在大挠度下承受均匀侧向压力的预屈曲或后屈曲梁的响应。由于可能会发生卡扣现象，因此采用了圆柱弧长技术。首先，提供两项比较研究以确保所开发配方的有效性和效率。此后，给出了新的数值结果，讨论了温度变化，GPL的重量分数，GPL的分布方式和边界条件的影响。