How to model stacked beams using Rigid Links

Simply specify the member “类型” 作为 “刚性连杆” to create a member that acts as a Rigid Link. When this is done you will see that the rigid link is drawn with a light-grey color and has an “[R” 旁边的符号:

刚性链接可用于定义涉及堆叠梁或构件的结构之间的刚性连接. They are often thought of as imaginary stiff links that join members so they can translate and/or rotate together. 刚性连杆也可用于手动控制构件偏移. 另外, 您可以更改刚性链接中的固定/释放，以控制它对所连接对象的作用力和影响.

Looking at the analysis results, you can see that as the top beam is loaded, and deflects, so does the beam below:

Member design checks will still run, 然而, it is important to consider the limitations of the software in understanding the unbraced lengths and member end fixities. In this scenario, the Lb should be adjusted according to your design needs.

C3.1.2.1-6 2: Using Custom Shapes in Section Builder

An alternative method to the above is using the SkyCiv Section Builder to model two models on top of each other, and treating it as one element:

This will use FEA to calculate the geometric properties of this ‘single’ 部分. 然后它将使用这些几何属性以及整个线元素. 可以在以下文档页面上查看有关此方法的更多信息: Composite and Built-up Shapes in SkyCiv

结果比较

When modeling the two methods together, the results are quite consistent for deflection:

由于成员仅在沿梁的某些点处链接, 梁的连通性存在差异. In the bottom (Section Builder Method), the element is treated as one piece, whereas in the Rigid Link method, it is only connected at 3 points along the beam’s span.