Finite Element Homework Solution

How to Solve Finite Element Homework Problems with Ease

Finite element method (FEM) is a powerful numerical technique for solving complex engineering problems involving partial differential equations. FEM can handle various types of boundary conditions, geometries, materials, and loads. However, FEM also requires a lot of mathematical and computational skills, which can make it challenging for students to complete their homework assignments.

If you are struggling with finite element homework problems, don't worry. There are some tips and tricks that can help you master this subject and ace your assignments. Here are some of them:

Review the theory and concepts. Before you start working on any problem, make sure you understand the underlying theory and concepts of FEM. Review the lecture notes, textbook chapters, or online resources that cover the topics related to your problem. Pay attention to the assumptions, approximations, and limitations of FEM. Also, review the basic concepts of linear algebra, calculus, and differential equations that are essential for FEM.

Choose an appropriate element type and mesh. Depending on the problem domain, boundary conditions, and desired accuracy, you need to choose an appropriate element type and mesh for your FEM analysis. Element types can be classified into one-dimensional (bar, beam, truss), two-dimensional (triangle, quadrilateral, shell), or three-dimensional (tetrahedron, hexahedron, solid) elements. Mesh is the discretization of the domain into a finite number of elements and nodes. You need to ensure that your mesh is fine enough to capture the variations of the solution, but not too fine to cause excessive computational cost.

Formulate the element equations. For each element in your mesh, you need to formulate the element equations that relate the nodal displacements (or other unknowns) to the applied loads (or other knowns). This can be done by using various methods, such as direct method, variational method, weighted residual method, or Galerkin method. The element equations can be written in matrix form as [K]e{d}e = {f}e, where [K]e is the element stiffness matrix, {d}e is the element displacement vector, and {f}e is the element load vector.

Assemble the global equations. After obtaining the element equations for all elements in your mesh, you need to assemble them into a global system of equations that governs the entire domain. This can be done by using a scatter matrix [L]e that maps the local nodal numbers to the global nodal numbers. The global system of equations can be written as [K]{d} = {f}, where [K] is the global stiffness matrix obtained by summing up [L]e[K]e[L]e over all elements, {d} is the global displacement vector obtained by stacking up {d}e over all elements, and {f} is the global load vector obtained by summing up [L]e{f}e over all elements.

Solve for the unknowns. Once you have assembled the global system of equations, you need to solve for the unknown nodal displacements (or other unknowns) by using various methods, such as direct methods (Gauss elimination, LU decomposition), iterative methods (Jacobi method, Gauss-Seidel method), or sparse matrix methods (conjugate gradient method). You may also need to apply boundary conditions (such as prescribed displacements or forces) to reduce the size of the system or to ensure its uniqueness.

Evaluate the results. After obtaining the solution vector {d}, you need to evaluate the results by calculating various quantities of interest, such as stresses, strains, reactions, errors, or convergence rates. You can use interpolation functions or shape functions to obtain these quantities at any point within an element or on its boundary. You can also use post-processing tools or software to visualize and analyze your results graph aa16f39245