Study Types

The software offers the following types of studies:

Static (or Stress) studies

Static studies calculate displacements, reaction forces, strains, stresses, and factor of safety distribution. Material fails at locations where stresses exceed a certain level. Factor of safety calculations are based on a failure criterion. The software offers 4 failure criteria.

Static studies can help you avoid failure due to high stresses. A factor of safety less than unity indicates material failure. Large factors of safety in a region indicate low stresses and that you can probably remove some material from this region.

Frequency studies

A body disturbed from its rest position tends to vibrate at certain frequencies called natural, or resonant frequencies. The lowest natural frequency is called the fundamental frequency. For each natural frequency, the body takes a certain shape called mode shape. Frequency analysis calculates the natural frequencies and the associated mode shapes.

In theory, a body has an infinite number of modes. In FEA, there are theoretically as many modes as degrees of freedom (DOFs). In most cases, only a few modes are considered.

Excessive response occurs if a body is subjected to a dynamic load operating at one of its natural frequencies. This phenomenon is called resonance. For example, a car with an out-of-balance tire shakes violently at a certain speed due to resonance. The shaking decreases or disappears at other speeds. Another example is that a strong sound, like the voice of an opera singer, can cause a glass to break.

Frequency analysis can help you avoid failure due to excessive stresses caused by resonance. It also provides information to solve dynamic response problems.

Buckling studies

Buckling refers to sudden large displacements due to axial loads. Slender structures subject to axial loads can fail due to buckling at load levels lower than those required to cause material failure. Buckling can occur in different modes under the effect of different load levels. In many cases, only the lowest buckling load is of interest.

Buckling studies can help you avoid failure due to buckling.

Thermal studies Thermal studies calculate temperatures, temperature gradients, and heat flow based on heat generation, conduction, convection, and radiation conditions. Thermal studies can help you avoid undesirable thermal conditions like overheating and melting.
Design Studies Optimization Design Studies automate the search for the optimum design based on a geometric model. The software is equipped with a technology to quickly detect trends and identify the optimum solution using the least number of runs. Optimization Design Studies require the definition of the following:

Goals

State the objective of the study. For example, minimize material. If you do not define goals, the software performs a Non-Optimization Design Study.

Variables

Select the dimensions that can change and set their ranges. For example, the diameter of a hole can vary from 0.5” to 1.0” while the extrusion of a sketch can vary from 2.0” to 3.0”.

Constraints

Set the conditions that the optimum design must satisfy. For example, stresses, displacements, temperatures should not exceed certain values and the natural frequency should be in a specified range.

Nonlinear studies In some cases, the linear solution can produce erroneous results because the assumptions upon which it is based are violated. Nonlinear analysis can be used to solve problems with nonlinearity caused by material behavior, large displacements, and contact conditions. You can define static as well as dynamic studies.
Linear Dynamic studies When inertial and damping effects cannot be ignored, static studies do not give accurate results. Linear dynamic studies use natural frequencies and mode shapes to evaluate the response of structures to dynamic loading environments. You can define:
  • Modal time history studies to define loads and evaluate response as functions of time.
  • Harmonic studies to define loads as functions of frequency and evaluate the peak response at various operating frequencies.
  • Random vibration studies to define random loads in terms of power spectral densities and evaluate the response in terms of the overall root mean square values or power spectral densities at various frequencies.
  • Response Spectrum studies to estimate peak responses over time for a system subjected to a particular base motion described in terms of a design spectrum.
Drop Test studies Drop test studies evaluate the effect of dropping a part or an assembly on a rigid or flexible floor. You can use drop test studies to simulate the impact of the model with a rigid or flexible planar surface.
Fatigue studies Repeated loading and unloading weakens objects over time even when the induced stresses are considerably less than the allowable stress limits. This phenomenon is known as fatigue. Linear and nonlinear structural studies do not predict failure due to fatigue. They calculate the response of a design subjected to a specified environment of restraints and loads. If the analysis assumptions are observed and the calculated stresses are within the allowable limits, they conclude that the design is safe in this environment regardless of how many times the load is applied. Fatigue studies evaluate the consumed life of an object based on fatigue events and S-N curves. You can base the fatigue calculations on stress intensity, von Mises stresses, or maximum principal alternating stresses.
Pressure Vessel Design studies Combine the results of static studies with the desired factors. Each static study has a different set of loads that produce corresponding results. These loads can be dead loads, live loads (approximated by static loads), thermal loads, seismic loads, and so on. The Pressure Vessel Design study combines the results of the static studies algebraically using a linear combination or the square root of the sum of the squares (SRSS).
2D Simplification studies You can simplify certain 3D models by simulating them in 2D. 2D simplification is available for static, nonlinear, pressure vessel design, thermal studies, and design studies. You can save analysis time by using the 2D simplification option for applicable models. 2D models require fewer mesh elements and less complex contact conditions compared to the 3D models. After running the analysis, you can plot the results in 3D.