Finite Element Method

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Tarea Diseño y Manufactura Asistidos Por Computadora Mind Map on Finite Element Method, created by César Pineda on 15/05/2016.
César Pineda
Mind Map by César Pineda, updated more than 1 year ago
César Pineda
Created by César Pineda over 9 years ago
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Finite Element Method
  1. General procedure
    1. Discretise the structure or continuum into finite elements.
      1. Specify the approximation equation.
        1. Determine the shape functions for each element.
          1. Formulate the properties of each element.
            1. Determine stiffness matrices and equivalent load vectors for all elements.
              1. Assemble elements to obtain the finite element model of the structure or continuum.
                1. Apply the known loads
                  1. Apply boundary conditions.
                    1. Solve simultaneous linear algebraic equations
                      1. DOF
                        1. nodal displacements in stress analysis
                          1. nodal temperatures in heat transfer analysis
                          2. stress analysis
                            1. Compute stress
                            2. heat transfer analysis
                              1. compute temperature
                                1. Interpret results
          2. Advantages of FEM
            1. Model complex shaped bodies quite easily.
              1. Handle several load conditions without difficulty.
                1. Handle different kinds of boundary conditions.
                  1. Include dynamic effects.
                    1. Vary the size of the elements to make it possible to use small elements where necessary.
                      1. Handle time-dependent and time-independent heat transfer problems.
            2. Engineering Applications
              1. Mechanical Desing
                1. Stress concentration problems
                  1. Stress analysis of pressure vessels
                    1. Composite materials
                      1. Linkages and gears
                      2. Electrical machines and electromagnetics
                        1. Steady state analysis of synchronous and induction machines
                          1. eddy current and core losses in electric machines
                            1. magnetostics
                            2. Biomedical engineering
                              1. Stress analysis of eyeballs
                                1. bones and teeth
                                  1. load-bearing capacity in plant and prosthetic systems
                                    1. mechanics of heart values
                                    2. Nuclear engineering
                                      1. Analysis of nuclear pressure vessels and containment structures
                                        1. Steady state temperature distribution in reactor components
                                      2. Degrees of freedom(DOF)
                                        1. Specify the state of the element. They also function as ‘handles’ through which adjacent elements are connected. DOF are defined as the values (and possibly derivatives) of a primary field variable at nodal points
                                        2. What is FEM?
                                          1. FEM is a powerful tool for the numerical solution of a wide range of engineering problems.
                                            1. The basic concept in the physical interpretation of the FEM is the sub-division of the mathematical model into disjoint (non-overlapping) components of simple geometry called finite elements
                                          2. Boundary conditions
                                            1. Avoid the possibility of the structure moving as a rigid body. Two approaches are used for handling specified displacement boundary conditions.
                                              1. Elimination approach
                                                1. Penalty approach
                                              2. Variational Formulation
                                                1. The Total Potential Energy Functional (TPE)
                                                  1. Relation between strain energy density and external energy
                                                  2. The Minimum Potential Energy Principle (MPEP)
                                                    1. states that the actual displacement solution u(x) is that which renders Pi stationary
                                                  3. ANSYS
                                                    1. It is one of the finite element analysis computer programming software.
                                                      1. ANSYS-Mechanical product is designed for analysing
                                                        1. static
                                                          1. structural and thermal
                                                            1. linear and non-linear
                                                              1. buckling
                                                                1. sub-structure
                                                                  1. acoustics
                                                                    1. dynamic/transient
                                                                  2. It enables users to solve a wide variety of analyses in mechanical engineering applications
                                                                  3. Finite Element Discretisation
                                                                    1. Decompose the TPE functional into a sum of contributions of individual elements.
                                                                      1. The same decomposition applies to the internal and external energies, as well as to the condition of MPEP
                                                                        1. Using the fundamental lemma of variational calculus, it can be shown that implies that for a generic element (e) we may write:
                                                                          1. This variational equation is the basis for the derivation of element stiffness equations once the displacement field has been discretised over a bar element.
                                                                    2. By César Pineda Leonardo
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