**CAD:** 3D solid modeling, dimensioning and tolerances, rendering, animation.

**FEA:** Finite Element (FEA) Analysis and simulation of stress, pressure, temperature, flow velocity distribution is space and time.

**Failure Mode Effect and Analysis (FMEA):** Extensive failure modes and effects analysis, and design iteration.

# FEA (Finite Element Analysis)

Finite element analysis (FEA) software tools implements the physics based mathematical equations and numerical solutions in the background. All general purpose FEA software tools (ANSYS, Abacus etc.) provide a graphical user interface (GUI) to define the problem and desired simulation conditions: that it to define the 3D geometry, material properties (i.e. a rectangular plate made of cast aluminum), simulated conditions (externa load conditions and boundary conditions). Then the FEA software tool provides tools to automatically or customizer finite element mesh generation, constructs the back physics based equations and solves them using a selected numerical solution method. The result are then presented in the form of field variable distribution over space (for static simulations) and time (for dynamic simulations). For instance, the simulated results can be stress, strain, temperature, pressure, fluid speed as function of location in space (x,y,z) and time (t).

The FEA analysis process is generally described in three stages: 1. pre-processing stage where, geometry, material, simulation conditions (external inputs, boundary conditions, initial conditions) are defined and mesh is generated using the GUI tool. 2. Solver phase where the set of FEA equations are solved to simulate the conditions and predict the results. This phase can be done also interactive mode or in batch mode. Batch mode is more appropriate when a given product is to be simulated for many different parameters and external input conditions. A set of simulations can be run in batch mode 3. Post-processing stage is evaluating the results, i.e. displaying the stress distribution over the product for the simulated case. If the simulated case is dynamic, than the results can be animated over time for realistic presentation of the results. The engineer must have a solid understanding of the physics of the problem and how FEA software works. Using different FEA software packages is a simple matter of learning the GUI they provide. We must also select FEA software package that implements the appropriate physics based mathematical equations in the background, i.e. stress-strain relations, heat, energy and temperature, fluid flow and pressure relations.

# FMEA Process

- Identify different failure modes
- Analyze consequences of failures at different levels
- Estimate probability, severity and detection of failures
- Quantify risks involved in each failure mode
- Early identification and mitigation of potential failures
- Minimize late changes and warranty costs
- Helps with design choices with trade-off analysis
- Involves root cause and 5-why analysis