Henry H. Fong

In the medical-device industry, manufacturers use FEA to analyze implants such as stents. Designers must consider the nonlinear behavior, material, and geometric design of these metallic stents. Today implants are analyzed using nonlinear FEA codes like Ansys, Abaqus, and MSC.Marc that allow creating custom devices such as gender-specific knee implants. Patient-specific cartilage, tendons, tissues, blood vessels, skin, and muscles are considered when describing their time-dependent mechanical behavior.

FEA is an approximate numerical analysis technique used to solve a variety of engineering problems. It got its start in the mid-1950s with two seminal papers written by academic and aerospace researchers that became the basis of the finite element method (FEM). Starting in the 1960s, FEM researchers began to extend the method beyond linear structural analysis to nonlinear FEA and other engineering disciplines such as fluid dynamics, heat transfer, soil mechanics, wave propagation, and electromagnetics. The first industry to use FEA techniques was the aircraft industry, followed by the automotive and energy industries.

In the early 1970s, four commercial, or proprietary, general-purpose FEA codes appeared: Stardyne from MRI, MSC/Nastran from the MacNeal-Schwendler Corp., Ansys from SASI, and Marc - a general-purpose, nonlinear FEA code. MSC/Nastran was primarily used by FEA engineers in the aerospace and automotive companies, while Ansys and Marc were mostly used in the energy and manufacturing industries. These codes were written in Fortran, typically ran in “batch mode” on big IBM mainframes (with punch cards as input), and the jobs would generally take 1 to 2 days.

The 1970s and 1980s saw the first computational fluid dynamics (CFD) codes: Fluent, Star-CD, and Fidap. And on the nonlinear FEA side, Abaqus from HKS was developed. PCs became popular in the 1980s, and the first PC FEA codes appeared, such as Algor and Cosmos/M. Special-purpose codes also were developed for kinematics, acoustics, electromagnetic, and plastics injection-molding analysis.

Today the future of FEA is bright, thanks to cheaper and faster computers, and code improvements. With iPods and Blackberries everywhere, is it conceivable that in the not-too-distant future, an engineer might carry a hand-held computer and perform on-the-spot FEA? My opinion: it's a nice thought, but not likely. For the next five years, such nonlinear FEA (or crash or CFD) number-crunching simulations of a complex model will still likely be done on a moderately-sized HPC cluster, of 16 to 64 processors or cores. In the biomedical field, remember that the human body is nonlinear in behavior. When it comes to fully understanding the complexities of the human body, we still have a long way to go.

In 2006 and 2007, I visited a dozen manufacturers and organizations in five major cities in India and China. I was blown away by how advanced their MCAE and IT technologies were, including software, hardware, grid computing, and applications, and how competent their FEA engineers and IT professionals appeared to be. The young Indian and Chinese engineers asked me perceptive questions. They wanted to find out what's happening in the West. Now, they possess the financial resources to purchase whatever FEA software, hardware, and infrastructure they need to help improve their global competitiveness. Give them another three years - and watch out!