Derek Board

Rigid Angular Impact Responses of a Generic Steel Vehicle Front Bumper and Crush Can: Correlation of Two Velocity-Measurement Techniques

This study presents experimental investigations of generic steel vehicle front bumper and crush can (FBCC) assemblies subjected to a 30° front-angular impact. There is a lack of studies regarding component level tests with FBCCs. As vehicles aim to decrease weight by applying lighter-weight material to vehicle structures, component level studies become important. Computer aided models will then be valuable tools to assess performance of these structures. Thus, a novel component level test procedure is valuable to aid in CAE correlation. A sled-on-sled testing method was used to perform all the tests reported here. Impact speed was optimized to minimize bottoming-out force for this type of test. The speed of the impactor-sled was obtained based on two measurement techniques, namely: high-speed cameras and accelerometers. Several high-speed cameras were used at different locations. The sled and bumper motions were monitored using video targets. A triaxial accelerometer system was utilized to measure off-axis accelerations of the sled-beam. The results showed that good correlation exists between the two methods for measuring the sled velocity. The accelerometer data were used to generate force-time history plots based on Newton’s second law. The force-time history and force-displacement curves from different FBCC specimens were consistent and in good agreement with respect to each other with a low coefficient of variation calculated.

Force-Time History Assessment of a Generic Steel Vehicle Front Bumper and Crush Can Subjected to a Rigid Center Pole Impact

In this study, generic steel vehicle front bumper and crush cans (FBCC) were impacted against a rigid pole. The majority of studies regarding pole impact tests are related to full vehicle testing. There is a lack of studies regarding component level tests with FBCCs. Component level studies are important as vehicles utilize lighter-weight materials to vehicle structures in order to decrease weight. Computer aided models will then be helpful to assess performance of these structures. Thus, a novel component-level test procedure is valuable to aid in CAE correlation. A sled-on-sled testing method was used to conduct the tests. Two approaches were considered to assess force-time history, namely: direct force measurement and Newton’s second law. Applied impact force was directly measured by a load wall located behind the rigid pole. The load wall consisted of two uniaxial PCB 1204-03A load cells. Each load cell had a diameter of 6.06″ (153.9 mm) and load capacity of 50 klb (222 kN). A total of six accelerometers were used in the sled system. The off-axis accelerations of the sled-beam were also measured using a triaxial accelerometer system mounted on the left side of the beam. Two types of damped accelerometers were used in this study: Endevco 7264-2000 G piezoresistive and Measurement Specialties A40.