Impact Sled – How Does Your Component Stack Up?

Crash testing has evolved significantly over the last several decades. Currently, today’s vehicles are designed and developed much earlier in their automotive life cycle. This shift has pushed out conventional technologies such as physical testing with engineers relying heavily on evaluating vehicle subsystems in unique ways. The challenge to maximize structural integrity and provide the highest level of occupant protection during crash events is a constant battle waged over years of material, dynamic and quasi-static component, dynamic sled, full vehicle crash, and CAE simulation testing. The impact sled provides many advantages to this early development effort in allowing engineers to create models using data collected from these tests and use it to correlate their models efficiently and effectively.

To complicate it further, advanced vehicle architecture and new technologies require significant attention to detail when developing a test plan that includes crash simulation. Today’s crash tests are increasingly complicated to reflect the changes in vehicle mass, center of gravity, and overall vehicle size. The push towards electrification also requires strict safety measures which push the limits of current crash labs in protecting personnel, equipment, and the subject vehicles from potential catastrophic events. An example of this is shown in the CAE model example below.

Managing crash energy when dealing with an elective vehicle requires a new approach. While conventional front-end components like engines and transmissions are designed to manage crash energy, EV vehicles do not have these types of components, and the front end is largely empty space. Designers and engineers are using these cavities to redefine the crush zone and its applicability to being used to manage the required crash energy. Additionally, to protect the high-voltage batteries typically located beneath the floor, the surrounding vehicle structure must be modified to withstand impacts from all directions.

MGA’s Dynamic Impact Sled has been in service at the Troy, Michigan location since 2020. Significant improvements have been made to the system in the last few years. This sled was previously introduced at the SAE World Congress in 2020 under the paper entitled, Kaleto, H., Pinelli, A., Briskey, J.P., Gizowski, J.W. et al., “An Innovative Approach to Component Testing Using an Impact Sled,” SAE Technical Paper 2020-01-1331, 2020, doi:10.4271/2020-01-1331.

The variety of vehicle subsystems today requires more unique evaluation methods in test laboratories to provide reliable data for virtual crash analysis and validate CAE models. Sled testing methodology is an efficient and economical way to evaluate vehicle safety components, offering economic advantages by allowing multiple compliance and component evaluations with a single vehicle. With the switch to virtual analysis as a global trend, the impact sled system becomes critical and more valuable, as it provides physical data from components or subsystems that correlate with CAE models early in the development process.

MGA offers an extensive range of impact conditions with our dynamic impact sled ranging from singular component to multi-system level evaluations.  Single component studies typically test components such as frame rails, bumper beams, side sill, and other various energy absorbing components.  These components are secured to a static barrier measuring five feet in height and eight feet in width, which is secured to a substantial reaction mass.  The barrier face is designed to be flexible, allowing for a wide variety of test samples and fixtures.  There are three primary impact carriages, each varying in mass, to which different impact forms are attached for specific test modes.

Recently, MGA performed a test to showcase the system-level capability of the impact sled system. An industry trend towards early correlation with CAE models to specific system-level impact is driving many activities.  A 100% overlap crash test, also known as a full-frontal test, was the subject of this evaluation.  The 100% overlap is an industry-standard test as a safety evaluation where the front of a vehicle collides with a rigid barrier, impacting the entire width of the subject vehicle’s front end.  This test assesses the vehicle’s structural integrity and occupant protection during a simulated head-on collision. 

For our demonstration, the front structure of a typical sedan was fixtured rigidly to the static barrier.  The sled’s impact carriage slides on linear bearings to reduce friction and boasts a flat impact face that is 800 mm tall by 1,800 mm wide.  The carriage impacted the vehicle structure at a velocity of 48 kph with a payload of 1,500 kg.  Various subsystems are painted different colors to match typical full vehicle crash tests. Aside from the accelerometer sensor data taken from the impact sled carriage (see data output below), the high-speed video provides comprehensive insight regarding the energy-absorbing performance and deformation patterns of the different structures.  Depending on the project, post-test 3 dimensional scans are required to provide an overlay of a CAE model. 

If you would like to see a demonstration test or discuss a potential test project, click here to fill out a request form on our website.