CAE Simulation: How It Works and Why It Matters

Computer-aided engineering (CAE) simulation works by using computers to divide a 3D model of a product into smaller elements; applying loads and boundary conditions to geometry; and then solving a stiffness matrix to determine the resulting behavior and response.

CAE simulation empowers product development companies to be on the leading edge of their industry and quick to market. Let’s take a deeper dive into how it works and how it can benefit you.

Areas for CAE Simulation

CAE simulation can be used for a variety of analyses including the following:

• Structural analysis finds the stresses, strains, and displacements for objects under loading, which can be static or dynamic (changing as a function of time or frequency).
• Modal analysis determines the natural frequencies and mode shapes of an object. Knowing these modes helps avoid resonance due to nearby vibration sources.
• Thermal analysis calculates the temperatures and heat flux for objects experiencing conduction, convection, and radiation. The analyses can be steady-state (at equilibrium) or transient (over time).
• Fluid analysis evaluates the movement of liquids and gases around and through our parts to measure temperature, pressure, flow velocity, and vortices.

Image: A fluid flow study of a turbine engine in Creo.

How It Works

The four main inputs for structural, modal, thermal, or fluids analyses are:

1. The element mesh.
2. Material properties.
3. Constraints.
4. Loads.

The Mesh represents the physical object to be analyzed and/or the fluid (liquid or gas) in or around it. Since most parts and assemblies are too complex to solve with closed-form equations, numerical problem solving methods take a “divide and conquer” approach. CAE simulation tools break up a product’s volume into smaller elements – tetrahedra (pyramids), blocks (rectangles), and wedges (extruded triangles). The nodes (corners) of these elements are used to construct a “stiffness matrix” of the model.

Material Properties describe how objects in the real world react to loads. Common material properties for CAE simulation include density, Young’s modulus, Poisson’s ratio, coefficient of thermal expansion, thermal conductivity, and specific heat capacity.

Constraints represent the real-world boundary conditions in which a physical object is held down or some kind of interface condition like temperature.

• Structural constraints prevent motion of an object.
• Thermal constraints include known fixed temperatures and convection conditions.

Modal analyses can be constrained or unconstrained. Fluids analyses need an outlet pressure and at least one inlet condition like pressure, mass flow, or flow velocity. Constraints are essential because they allow the equations from the stiffness matrix to be reduced to a solvable number of variables.

Loads simulate the real-world conditions that you expect your product to encounter. Structural loads include forces, moments, pressure, gravity, and centrifugal acceleration. Heat loads like heat flows and heat fluxes can be used in both thermal and fluid analyses.

When these four inputs are defined, the analysis can be run. Then the user can generate numerical and graphical results to determine factors and margins of safety. These values determine if the product will survive or needs re-design.

Why It Matters

CAE simulation provides your product development organization with a differentiator to get to market faster and at a lower cost by:

• Completing initial concept and detailed design with fewer iterations.
• Generating prototypes with first-time quality that give you a higher level of confidence that they are validated for their operating conditions.
• Narrowing your test program down to only those runs necessary to verify your product.

You are using a virtual version of your product to reduce development time, manufacturing tooling, and material and resource costs. More reliable products lead to higher customer satisfaction as well as lower service and warranty costs for the manufacturer.

When I designed drones at Amazon, CAE simulation tools enabled us to select between different design alternatives without having to prototype and test. They also enabled us to design structural components that did not resonate at our motor frequencies. Austrian sports car and motorcycle manufacturer KTM reports a 15% reduced time-to-market and 10% increased fuel economy due to CAE simulation tools.

Can CAE Simulation Benefit You?

If you do not already employ CAE simulation in your workflows and processes, you could be missing out on efficiency. Worse, you could be providing your competitors with an advantage. If you are looking to improve schedule and budgets while making better products, CAE simulation should be one of the first places you look.