Virtual product development (VPD) encompasses a wide variety of software tools that take a product from conception to production, enabling the engineer to design completely on the computer. In this process, engineers replace prototypes with computer evaluations, reducing the time and expense of getting products to market.
While numerous 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. They will consider more physical phenomena, instead of assumptions, resulting in a truer representation and replication of events.
| 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.
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 calculations. Engineers now use CAD, FEA, kinematics, and simulation software packages to eliminate large-scale design errors.
Although no one package contains the elements needed to replace prototypes completely, existing tools reduce testing at the prototype stage. This reduction has enabled companies to develop products faster, thus saving money, without compromising safety.
VPD today. Existing software tools including CAD, FEA, kinematics, and simulation software packages, 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. Kinematics software represents motion in mechanisms and yields forces at each instance in time, assuming that the components are rigid.
In the last few years, interfacing between software packages has enabled engineers to use two or more packages together more effectively. 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.
Future of VPD. In the VPD products of the future, interfacing will give way to integration. By "integration" I mean that one package will simultaneously perform several functions, which could previously be achieved only by harnessing multiple software packages. Increased integration will eliminate the inefficiency inherent in transferring data.
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. Pressures, significant temperature gradients, or the flow of fluids 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 these phenomena, and will replicate the behavior of materials more accurately.
| Engineers at Selantic Industrier A.S. (Agotnes, Norway) performed a drop-test simulation with Algor’s Accupak/VE Mechanical Event Simulation software to determine the limits of a protection net for an 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.
By integrating a full range of physical phenomena simultaneously, VPD tools move from being based on assumptions to being based on physics. Current software tools require the user to make certain conjectures because they do not simulate exact physical behaviors.
A taste of tomorrow. Algor Accupak/VE Mechanical Event Simulation software has already achieved the integration of motion and flexing in a single process. Accupak/VE models bend, twist, stretch, and squash on the computer screen. The stresses produced by simulating the motion and flexing of the model can be viewed at the same time. Accupak/VE helps engineers 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 the real thing.
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 8.9 minutes--161 times faster--on the same computer. (Keep in mind, though, that processing times depend on many factors that vary with model geometry and setup as well as the event being simulated.)