In
a finite element analysis we determine the structural response of a part due to
the conditions in which it is placed. We determine the stress levels in the
part, how much the part will deform, how hot the part will get, and whether or
not the part will fail in service. This knowledge can be determined early in
the design process and can eliminate the need to build and test a prototype.
The basic process of conducting a finite element analysis is to build a computer
model of the part (using a CAD file if available), apply loads and boundary
conditions, solve the matrix equations, and interpret the results.
All types of finite element analysis begin with generating a computer model of
the part or system. Once the model is built several types of analysis can be
performed depending on the environment in which the part will be placed. Some
of these are discussed below.
Types of FEA.
Stress analysis.
Structural problems in elasticity can be solved using linear stress fea. Stress
and displacement response are the main results of a linear stress analysis.
These stress levels and deformations are critical in determining whether a
product will fail in service and to show conformance to design codes.
Vibration analysis.
Most problems in vibration are based on a linear stress analysis. The analyst
will expand on the static analysis by applying time varying loads and the
damping properties of the system. The results of a vibration analysis include
the natural frequencies and the dynamic response (stresses and displacements) of
a system to the time varying loads. The main design objective in vibration
analysis is to avoid destructive resonant frequencies in which the response
amplifies itself until the part fails. Vibration analysis can also used to
determine the fatigue life of a part.
Thermal fea analysis.
The thermal response of a part or system can also be determined using fea.
Temperature values, heat flow, and thermal stress can be critical for parts
placed in a thermal environment.
Non-linear fea Analysis. Nonlinear
analysis involves systems that have large displacements or advanced material
behavior such as plastic yielding. buckling, or failure. Another type of
non-linearity involves contact between the part and other parts. We have been
solving nonlinear problems since 1983 and have extensive experience in this
area.
Advanced fea Analysis. Many
structures and systems are placed in very complicated environments that
traditional fea methods have problems with. Some of these environments include
impact, severe post yield behavior, fracture surfaces, and coupled physics
environments. To tackle these complicated systems we turn to the explicit
methods developed by the defense industries.
Programs such as Abaqus, ADINA, ANSYS, and NASTRAN, can routinely handle
behaviour that traditional implicit methods have trouble with. A couple of
examples of these advanced problems would be drop testing, crash testing,
explosives, and forming problems. In addition explicit methods have very robust
contact capabilities and can be used to resolve a non-converging implicit
analysis.
