Each element contains nodes which are points were the elements are mathematically connected to one another. The idea of dividing a domain up into subdomains is the basic principle of how FEA works'
FEA consists of a computer model of a material or design that is stressed and analyzed for specific results. It is used in new product design, and existing product refinement. A company is able to verify a proposed design will be able to perform to the client's specifications prior to manufacturing or construction. Modifying an existing product or structure is utilized to qualify the product or structure for a new service condition. In case of structural failure, FEA may be used to help determine the design modifications to meet the new condition.
There are generally two types of analysis that are used in industry: 2-D modeling, and 3-D modeling. While 2-D modeling conserves simplicity and allows the analysis to be run on a relatively normal computer, it tends to yield less accurate results. 3-D modeling, however, produces more accurate results while sacrificing the ability to run on all but the fastest computers effectively. Within each of these modeling schemes, the programmer can insert numerous algorithms (functions) which may make the system behave linearly or non-linearly. Linear systems are far less complex and generally do not take into account plastic deformation. Non-linear systems do account for plastic deformation, and many also are capable of testing a material all the way to fracture.
How Does Finite Element Analysis Work'
FEA uses a complex system of points called nodes which make a grid called a mesh . This mesh is programmed to contain the material and structural properties which define how the structure will react to certain loading conditions. Nodes are assigned at a certain density throughout the material depending on the anticipated stress levels of a particular area. Regions which will receive large amounts of stress usually have a higher node density than those which experience little or no stress. Points of interest may consist of: fracture point of previously tested material, fillets, corners, complex detail, and high stress areas. The mesh acts like a spider web in that from each node, there extends a mesh element to each of the adjacent nodes. This web of vectors is what carries the material properties to the object, creating many elements.
A wide range of objective functions (variables within the system) are available for minimization or maximization:
Mass, volume, temperature
Strain energy, stress strain
Force, displacement, velocity, acceleration
Synthetic (User defined)
There are multiple loading conditions which may be applied to a system. Next to Figure 3, some examples are shown:
Point, pressure (Figure 3), thermal, gravity, and centrifugal static loads
Thermal loads from solution of heat transfer analysis
Heat flux and convection
Point, pressure and gravity dynamic loads
Each FEA program may come with an element library, or one is constructed over time. Some sample elements are:
Viscous damping elements
Many FEA programs also are equipped with the capability to use multiple materials within the structure such as:
Isotropic, identical throughout
Orthotropic, identical at 90 degrees
General anisotropic, different throughout