In this course, we discussed boundary conditions and loads to be used in structural analysis. Let’s summarize the key points from each lesson.

Determining which Support to Use

  • Supports are used to represent parts that are not present in the model but are interacting with it.
  • Supports help truncate the domain, which in turn helps in efficiently obtaining numerically accurate results without modeling parts of the geometry that are not of primary interest.
  • There are different types of support available, and choosing the appropriate support is essential as it assures that the simulation model will properly represent the boundary condition.
  • We discussed the different support types and showed which support to use for different situations.

Understanding the Need to Fully Constrain the Model

  • Always keep in mind the need to fully constrain the model.
  • The model should not be over-constrained; rather, we must have optimal boundary conditions to complete an analysis successfully and accurately.
  • Understand the importance of properly constraining the model and the best strategies that users may follow to achieve success.

Understanding when to Take Advantage of Symmetry

  • If the geometry, material orientation, loading, and expected response all exhibit symmetry about the same planes, we can take advantage of planar symmetry and only model a portion of the actual structure to reduce analysis run time and memory requirements.
  • Using Symmetry Regions in Ansys Mechanical can give more accurate and more computationally efficient solutions.
  • The Symmetry Region tool should not be used when all four symmetry requirements are not satisfied such as in modal or linear buckling analyses where non-symmetric modes are needed to be calculated.

Understanding the Difference Between Forces and Pressures

  • In 3D analysis, force and pressure loads are related to each other.
  • The major difference between force and pressure is how it is applied to the system.
  • Users can select either force or pressure to excite or load the model; however, one might be easier to use and more accurate than the other.

Understanding Inertial Loads

  • Gravitational acceleration can be included in a static analysis, but it may be a bit confusing for new users since parts should not move or accelerate in a static analysis.
  • Different types of inertial loads are available, such as acceleration, rotational velocity, rotational acceleration, and gravity.
  • The inputs needed for their definition in a static analysis are different.
  • Defining proper material properties is essential for carrying out a finite element analysis with inertial loads.
  • Inertia loads need to be interpreted in the context of a moving reference frame, and the equation of motion varies for static and dynamic analysis.

Performing a Thermal-Stress Analysis

  • Change in temperature produces thermal strain.
  • Constraining thermal expansion or contraction will produce stresses.
  • We receive the temperature distribution from thermal analysis and thermal strains from structural analysis.
  • We can map temperature results from thermal to structural analysis even when the geometry or mesh differ.