Virtual Product Development Tools Will Shorten Time to Market

Michael L. Bussler
President
Algor, Inc.
Pittsburgh, PA

Virtual Product Development (VPD) encompasses a wide variety of software tools that take a product design from conception through the beginning of production, helping the engineer to design by trial and error on the computer. In this process, engineers replace prototype testing with testing on the computer, which reduces the time and expense of getting products to market. While a wide variety of CAD, finite element analysis (FEA), kinematics and simulation software tools exist today, tomorrow’s VPD products will integrate these functions more tightly into a What-You-See-Is-What-You-Get environment and will consider more physical phenomena, resulting in truer representation and replication of real physical events.

Reduction of the Design Cycle is Good for Business.

The use of computers has already shortened the design cycle by automating work that used to be done literally by hand. We have come a long way since the days when paper and pencil were an engineer’s primary tools for drafting designs and doing hand calculations. Engineers now use CAD, FEA, kinematics and simulation software packages to eliminate large-scale errors in designs.

Although no one package contains all the elements to simulate reality well enough yet to replace prototype testing completely, existing tools are currently helping to reduce prototype testing. Reduction in prototype testing has enabled companies to develop products faster without compromising safety. The more efficient the design cycle is, the faster companies can fulfill consumer needs and desires and the more competitive and profitable the company is to its investors.

Engineers at Selantic Industrier A.S. performed a drop test simulation with Algor's Accupak/VE Mechanical Event Simulation software to determine the limits of a protection net for a new ELF offshore oil platform currently under development in the North Sea. Based on the initial mechanical event simulation results, Selantic engineers modified the net design by substituting a different material type and adding more termination points at the edges of the net. The final simulation revealed both deflections and stresses to be within the allowable limits.

The General State of VPD Today.

Existing software tools, including CAD, FEA, kinematics and simulation software packages, each offer different advantages. CAD software helps with design and manufacturing by representing components and assemblies visually. FEA software is useful for calculating stresses, usually at a single instance in time, provided that the engineer can make good assumptions about forces and boundary conditions and knows how to interpret the results. Kinematics software represents motion in mechanisms and yields forces at each instance in time, assuming that the components in the mechanism are rigid. Algor, Inc. offers Accupak/VE Mechanical Event Simulation software to simulate both motion and flexing in a single process for a mechanical device during a hypothetical "event", showing stresses on the moving model, which can be based on a CAD model or assembly.

In the last few years, interfacing between software packages has developed to enable engineers to more effectively use two or more packages together. For example, a CAD model can easily be converted to an FEA model. Furthermore, the maximum force from a kinematic analysis can be used as input for a static finite element analysis.

Integration is the Future of VPD.

The VPD products of the future will be more tightly integrated. By "integrated" I mean that one package will simultaneously perform several functions, which could previously be achieved only by harnessing multiple software packages. The development of increased integration will reduce the need to interface multiple software packages, eliminating the inefficiency inherent in transferring data. The engineer will be spared the effort now spent on repeatedly feeding back results between different packages.

I also foresee the integration of a wider range of physical phenomena. Stress caused by motion is not the only way that failure can occur. For example, pressures, significant temperature gradients or the flow of fluids such as water or air against an object can also induce forces, which can result in motion and stress. The VPD products of the future will include capabilities to account for all of those phenomena and will replicate the behavior of materials more accurately.

From Assumption-Based to Physics-Based.

By integrating a full range of physical phenomena simultaneously, VPD tools move from being assumption-based to being physics-based. Current software tools require the user to make assumptions because they do not simulate a full range of physical phenomena simultaneously. For example, linear static FEA software requires that the engineer make assumptions about loads and boundary conditions. Another example is that kinematic software assumes that the components are rigid. By simulating physical reality more completely, the need to make assumptions is eliminated.

A Taste of the Future.

Algor Accupak/VE Mechanical Event Simulation software has already achieved the integration of motion and flexing simulation in a single process. Accupak/VE models bend, twist, stretch and squash on the computer screen as a result of motion, and the stresses produced by the motion and flexing of the model can be viewed at the same time. Because this is a single process, Accupak/VE helps engineers to see the cause-and-effect relationship between motion, flexing and stress. The results are clear even to non-engineers.

Accupak/VE also integrates nonlinear material behavior. The Release 12 version of the entire Algor software line includes three enhanced nonlinear material models. Algor’s ongoing development of material models aims to represent real-world material behavior more accurately.

In addition, Accupak/VE interfaces with CAD systems and offers special "kinematic" elements to reduce run times in simulations with highly detailed models that look more like real components and assemblies than the simplified models that were previously used for their processing speed. Using the new kinematic elements, an engineer can simulate an event using a complete CAD solid model or assembly in a practical amount of time, yielding a computer simulation that performs as an actual virtual prototype. While Algor is still in the process of benchmarking how much faster kinematic elements are, preliminary test results are impressive. A 37,659-element model created from a CAD assembly completed one timestep in exactly 24 hours when regular finite elements were used. Using a combination of 7,622 regular and 30,037 kinematic elements, the same model completed one timestep in only 8.9 minutes – 161 times faster* – on the same computer. (*Processing times depend on many factors that vary with model geometry and setup as well as the event being simulated.)

In this simulation of a SolidWorks assembly, dynamic stresses are shown only on the spring. The other suspension components are modeled with Algor’s proprietary kinematic elements for faster processing.

Finally, Algor offers a range of FEA capabilities including linear and nonlinear stress, vibration and natural frequencies, heat transfer, electrostatics, fluid flow, piping design and composite materials so that multiple physical phenomena can be considered on the same model – a process known as multiphysics analysis. In the future, multiphysics simulations will be even more tightly integrated within the Algor environment.