A new joint modeling method for a beam-based analysis of a car body applied during the concept design phase is presented. The body-in-white (BIW) of a car mainly consists of thin-walled beams with closed cross-sections, the joints of which show a significant flexibility owing to higher-order deformation modes. The joint flexibility effect cannot be evaluated using conventional beam theories. Although a hybrid modeling method using shell elements for a joint region, condensed in the form of a superelement, can be employed, its increase in accuracy for the joint flexibility is marginal. This is because the interface of the shell-modeled joint and that of conventional beam elements is rigidly connected, and thus the flexibility of the shell elements of the joint disappears at the interface. In this investigation, a thin elastic layer is introduced to account for a flexible connection between the interfaces of the shell-modeled joint and those of the beam elements. By employing an absorption parameter, the stiffness of the thin layer is set such that the thin layer can represent not only the accurate flexibility of the shell-modeled joint, but also higher-order deformations such as distortion and warping of thin-walled beams that are connected to the joint. To determine the absorption parameter of a thin layer, a surrogate model is built with respect to the geometric parameters of the cross-section of a connected beam, joint angle, and wall thickness. The effectiveness of the proposed beam-joint modeling method is shown by solving two-beam joint problems with various cross-sections and the BIW of a passenger car.

在概念设计阶段施加提出了一种用于汽车车身的基于射束的分析的新的联合建模方法。汽车的车身的白车身（BIW）主要由薄壁梁封闭截面的，关节其中显示由于较高阶变形模式的显著灵活性。关节灵活性效果不能使用常规的光束的理论进行评价。虽然使用了接合区域的壳单元，在超单元的形式冷凝的混合建模方法，可以采用，其在准确度增加了关节的灵活性是有限的。这是因为壳建模关节的和常规的梁元件的接口，其被刚性地连接，从而在界面处的接合消失的壳单元的灵活性。本次调查中，薄的弹性层被引入到帐户用于壳建模的接头的接口和那些梁元件之间的柔性连接。通过采用吸收参数，所述薄层的刚性被设定为使得该薄层可以表示不仅壳建模的关节的准确的灵活性，但也较高阶变形诸如扭曲和薄壁梁翘曲那连接到接头。为了确定一个薄层的吸收参数，一个替代模型是建立相对于所连接的梁，关节角度，和壁厚的横截面的几何参数。所提出的波束联合建模方法的有效性是通过求解具有各种横截面和客车的BIW双光束关节问题所示。