Would you volunteer to drive into a brick wall? Probably not. Which is why computer simulations are crucial to auto safety.
Software lets engineers run crash tests inside computers rather than on roads. It also allows them to compare the performance of different designs early in the process while cars are still on the drawing board, saving money and injuries.
When Software Saves Lives
What actually happens during a car crash? How does each part of the car react? What are the specific effects on passengers? To design safer cars you need to fully understand accidents. Software simulations help uncover the deadliest dangers—and test solutions.
More than 30,000 people die every year on American roads. Too many—but far fewer than a generation ago, thanks largely to seat belts and knowledge gained from simulations.
Computers vs. Crashes
Software can simulate the real world. But it can’t replace the real world. So car design engineers combine information from virtual crashes and from actual crashes.
Simulations let engineers explore varied options early in the design process. But final, definitive tests, the basis for safety ratings, require smashing real cars.
Credit: © Consumer Reports
”Auto Issue,” Consumer Reports, April 2016
Results from crash tests impact a car’s safety ratings -a major consideration for many car buyers. Rave reviews and scientific data in trusted sources, like Consumer Reports, can instantly change a buyers’ perspective about a car.
Car Crash Simulation Software Makers and Users
Crashed Ford Taurus, 2008
Creating a Virtual Crash
Creating an actual car crash is easy (unfortunately). But how do you create a simulation?
Once designers have outlined a car’s basic form, they use the finite element method (FEM) to model its shape by plotting many interconnected points on the car’s surface.
Software then calculates how the forces in a crash would affect each of those points to determine the overall result of the impact.
Car model by George Washington University, 2012. Image courtesy of Livermore Software Technology Corporation.
Car crash simulation using LS-DYNA software, 2016
This virtual car simulation, shown in the program LS-DYNA, shows the FEM “mesh” covering the car. Each point in the mesh represents a series of calculations.
CAD in Auto Design
Appearance. Performance. Efficiency. Safety. Cost. Computer-aided design (CAD) lets car designers balance all these factors, simulating the performance and tweaking the look of each new model before building actual prototypes.
Auto manufacturers adopted many CAD techniques from aeronautical engineers, who pioneered the use of powerful computers to model the performance of aircraft designs.
1/5th-scale 2020 Buick Skylark concept model, 2014
From Concept to Construction
Software simulations play a part beyond crash tests. They touch every step, from design and engineering through production.
For example, fluid dynamics computations analyze aerodynamics to improve fuel efficiency. Performance tests provide feedback as the design evolves. And simulating the manufacturing process identifies ways to increase efficiency or reduce waste.
Courtesy of Murtazo Nazarov, Uppsala University (geometry courtesy of Volvo Car Corporation)
Minivan CFD simulation, 2008
To improve fuel economy, car manufacturers try to reduce wind resistance. Computational fluid dynamics (CFD) simulations show how air moves around a moving object, like this minivan, allowing designers to adjust its shape.
Top-1984 Camaro lift window outer panel (outlined) Middle-Stamped sheet metal. Lift window outer panel Bottom-CAD screenshot
There are many steps in designing, testing, and building a safe, stylish car. Software plays a central role in each.
DesignComputer-aided Design (CAD) software transforms ideas into images, showing how the car will look, and creating a data set representing the car.
“Mesh” EngineeringUsing the CAD data, a finite element method (FEM) engineer creates a graphical “mesh,” plotting each car part as a mosaic of small polygons called “elements.” Software assembles each individual element into a complete and structurally accurate mesh model of the car.
Simulated CrashFinally, engineers crash the car into a barrier—virtually—using powerful software to simulate the effect on each element. The system displays the results as a moving image, which engineers use as a guide to fine-tune the design.
The Origins of Crash Test Software
Software that makes cars safer was originally developed to help blow things up.
In 1976, John Hallquist at Lawrence Livermore National Laboratory (LLNL) created DYNA3D, which used the finite element method to measure the impact of nuclear bombs dropped at low altitudes. Its unique 3-D capabilities became the foundation for commercial software that simulated car crashes.
Photo by Julie Russell/Lawrence Livermore National Laboratory.
John Hallquist, 2014
John Hallquist is the creator of the earliest crash test software, LS-DYNA (originally called DYNA3D). He left LLNL in 1987 to start his own company, Livermore Software Technology Corporation, and now holds over 15 patents for his work.
John Hallquist creator of the earliest crash test software, LS-DYNA (originally called DYNA3D)
Graphics Help the Engineer
The earliest simulations produced pages of numerical data, which engineers had to interpret. Today, powerful computers turn this data into graphics, letting engineers watch moving images of car crashes, greatly simplifying their analysis of the results.
The more powerful the computer, the more complex, accurate, and easily interpreted the simulation.
Courtesy of Volkswagen AG & ESI Group
Comparison of simulated and physical crash test results of VW Polo simulation, 1986
The first car crash simulation from a major car manufacturer was Volkswagen’s test of its Polo car in 1986. The simulation had only 5,600 elements. Today simulations have millions of elements.
Crash Test Stands-Ins
Engineers want to know what happens to cars during crashes. Even more, they need to know what happens to passengers.
Before computer simulations, crash tests used animals, cadavers…and volunteers. But there’s only so much you can learn from a cadaver. And only so much you can do to a volunteer.
Photograph by Sean Haight/Courtesy of the Collision Safety Institute
Rusty Haight, ARC-CSI Crash Conference, Las Vegas, Nevada, June 4, 2012
Rusty Haight is the director of the Collision Safety Insititute—he's also the “Human Crash Test Dummy.” Haight holds the Guiness World Record for “Most Human Subject Crash Tests,” with over 1,000 crash tests.