The finite element method (FEM) is the most widely used method for solving problems of engineering and mathematical models. The process starts with the creation of a geometric model and then program subdivides the model into small pieces of simple shapes i.e. elements connected at common points i.e. nodes. Finite element analysis programs look at the model as a network of discrete interconnected elements.
Meshing is a very crucial step in design analysis. And in these blogs, we will study elements types available in SOLIDWORKS Simulation. There are five elements are available in SOLIDWORKS Simulation.
- First Order Solid Tetrahedral Elements:
First order (draft quality) tetrahedral elements model the first (linear) displacements field in their volume, along faces and edges. The linear, or the first order displacements field gives these element name: first order elements.
Each first order tetrahedral element has total of four nodes, one in each corner. Each node has three degrees of freedom, meaning that nodal displacements can be fully described by three translation components. The edges of first order elements are straight and the faces are flat. These edges deformation and faces must remain straight and flat after the elements experience deformation under an applied load. Each edge of the draft quality element is formulated by the equation of a line, y = Ax + B.
2. Second Order Solid Tetrahedral Elements:
Second order (high quality) solid tetrahedral elements model the second order (parabolic) displacements field and, consequently, first order (linear) stress field (note that the derivative of a parabolic function is a linear function). The second order displacements field gives these elements their name: second order elements.
Each second order tetrahedral element has ten nodes (four corner nodes and six mid-side nodes) and each node has three degrees of freedom. The edges and faces of second order solid After elements can assume curvilinear shapes if deformation the elements need to map to curvilinear geometry and/or during the deformation process when the elements deform under a load. Therefore, these elements map precisely to curvilinear geometry, as illustrated by the same below spider geometry.
Again, for demonstration purposes, excessively large (as compared to the model size) elements are used for this mesh. This mesh is not sufficiently refined for analysis, even though it uses second order elements that require a significantly less-refined mesh compared to that for first order elements. Each edge of the high-quality solid element can be formulated by the equation of a curve, y = Ax^2 + Bx + C.
3. First Order Triangular Shell Elements:
Analogous to first order solid elements, first order triangular shell elements model the linear displacements field and constant strain and stress along their faces and edges. The edges of first order shell clement are straight and must remain straight while the elements deform. Each first order shell element has three nodes (all in corners) and each node has six degrees of freedom, meaning that its displacements are fully described by three translation components and three rotation components.
4. Second Order Triangular Shell Elements:
Second order (high quality) triangular shell elements model the second order displacement field and the first order (linear) stress field. Each second order shell element has six nodes: three corner nodes and three mid-side nodes. The edges and faces of second order shell elements can assume curvilinear shapes in the meshing process when the elements need to map to curvilinear geometry and/or during the deformation process a load. This shell element mesh created with second order shell elements maps precisely to curvilinear geometry as illustrated in below elbow model.
5. Beam Elements:
Beam elements require defining the exact cross section so that the program can calculate the moments of inertia, neutral axes and the distances from the extreme fibers to the neutral axes. The stresses vary within the plane of the cross-section and along the beam. Each two-node beam element features six degrees of freedom at each node: three translation and three rotations. A structural member is automatically identified as a beam and meshed with beam elements. After you create the mesh, you can apply mesh controls to specify a different number of elements or element size for selected beams.