Nonlinear shell modeling is always accompanied by simplifying assumptions on some computational parameters. In the latest nonlinear model based on eight parameters, that considers the displacement field as third-order polynomials in all three directions of curvilinear system, rotational inertia and shear deformations are also included; however, nonlinear terms are eliminated from some dependent variables, in addition, curvature and torsion variations of the shell are also assumed linear. In this study, not only all the dependent variables were considered as nonlinear in a different approach, but curvatures and torsion nonlinearities also retained, and a complete and accurate model for thick shells of any shape was presented. The equations of motion of the system have been derived on the basis of Lagrange equations, and cylindrical shells under static and dynamic loads have been studied. In the case of static loading, it was seen, with increasing the shell thickness, the effects of nonlinear curvature and torsion were limited, but have a significant impact on post-buckling behavior of the shell, where noticeable large deformations have occurred. However, their effects in static loading were less than the dynamic case, especially the aftermath of the buckling. It was also observed in dynamic loading, while the nonlinearities of curvature and torsion raised the system frequency content, it also intensifies the vibration amplitude and changes the response style to the dynamic excitation.

非线性壳建模总是伴随着简化某些计算参数的假设。在基于八个参数的最新非线性模型中，将位移场视为曲线系统所有三个方向上的三阶多项式，还包括了旋转惯性和剪切变形。然而，非线性项从某些因变量中消除了，此外，壳体的曲率和扭转变化也被认为是线性的。在这项研究中，不仅以不同的方法将所有因变量视为非线性，而且还保留了曲率和扭转非线性，并提出了一个完整而准确的任何形状的厚壳模型。系统的运动方程是根据拉格朗日方程推导出来的，研究了在静态和动态载荷下的圆柱壳。可以看到，在静载荷的情况下，随着壳体厚度的增加，非线性曲率和扭转的影响受到了限制，但对壳体的屈曲后行为产生了显着影响，发生了明显的大变形。但是，它们对静态载荷的影响小于动态情况，尤其是屈曲的后果。在动态载荷下也观察到了这一点，尽管曲率和扭转的非线性增加了系统频率的含量，但也加剧了振动幅度并改变了对动态激励的响应方式。非线性曲率和扭转的影响是有限的，但是对壳体的屈曲后行为有显着影响，在壳体中发生了明显的大变形。但是，它们对静态载荷的影响小于动态情况，尤其是屈曲的后果。在动态载荷下也观察到了这一点，尽管曲率和扭转的非线性增加了系统频率的含量，但也加剧了振动幅度并改变了对动态激励的响应方式。非线性曲率和扭转的影响是有限的，但是对壳体的屈曲后行为有显着影响，在壳体中发生了明显的大变形。但是，它们对静态载荷的影响小于动态情况，尤其是屈曲的后果。在动态载荷下也观察到了这一点，尽管曲率和扭转的非线性增加了系统频率的含量，但也加剧了振动幅度并改变了对动态激励的响应方式。