This study compares the deformation characteristics of steel and carbon fiber composite (CFC) front* bumper crush can (FBCC) assemblies when subjected to a full-overlap frontal impact into a rigid wall. Both the steel and composite bumper tests were conducted using a sled-on-sled testing method. Several high-speed cameras (HSCs) and accelerometers were used to gather kinematics data. The applied forces were measured using a load cell wall. For each test, the collective set of data was filtered, sorted, and analyzed to compare the performance of the steel and CFC bumpers. Similarities in Acceleration-Time plots suggested resemblance in the deformation patterns for both types of bumper systems. The difference observed in the velocity and displacement time histories was because of the brittle nature of the composite material. The velocity-time history of the CFC FBCC had two distinct patterns, events suggesting adhesive bond failure between the bumper beam and the crush cans, which was validated through video tracking. Post-impact photographs showed a clear difference between the material behavior of composite and steel bumpers when subjected to high-velocity impact. The steel bumper beam was bent uniformly with intact, equally crushed crush cans. The composite beam was cracked in the middle and was detached from the crush cans.

This research article presents the crashworthiness response of carbon fiber composite front bumper crush can (FBCC) assembly subjected to 40% offset frontal impact loading. Automobile manufacturers continue to strive for overall vehicle weight reduction while maintaining or enhancing safety performance. Therefore, the physical testing of lightweight materials becomes extremely important under a crash scenario in order to apply them to automotive structures to reduce the overall weight of the vehicle. In this study carbon fiber/epoxy lightweight composite material is chosen to develop frontal bumper beam crush can assemblies. Due to lack of available studies on carbon fiber composite FBCCs assemblies under frontal offset crash scenario, a new component-level experimental study is conducted in order to develop data that will provide assistance to CAE models for better correlation. A sled-on-sled testing method was utilized to perform tests in this study. 40 % offset frontal tests on FBCC structures were conducted by utilizing three high-speed cameras (HSCs), several accelerometers and load wall. Impact histories i.e. crash pulse, force-time history, force-displacement, impact characteristics and deformation patterns from all FBCC tests were consistent. The standard deviation and coefficient of variance for the energy absorbed were very low suggesting the repeatability of the 40% offset tests. Excellent correlation was achieved between video tracking and accelerometers results for time histories of displacement and velocity. Post-impact photographs showed the progressive crushing of composite crush cans, bumper beam/crush can adhesive joint failure located on unimpacted side and breakage of the bumper beam due to the production of shear stresses as it is stretched due to its curvature after hitting the sled.

This research study highlights the testing method and relevant results for assessing impact performance of a carbon fiber composite front bumper crush can (FBCC) assembly subjected to full frontal crash loading. It becomes extremely important to study the behavior of lightweight composite components under a crash scenario in order to apply them to automotive structures to reduce the overall weight of the vehicle. Computer-aided engineering (CAE) models are extremely important tools to virtually validate the physical testing by assessing the performances of these structures. Due to lack of available studies on carbon fiber composite FBCCs assemblies under the frontal crash scenario, a new component-level test approach would provide assistance to CAE models and better correlation between results can be made. In this study, all the tests were performed by utilizing a sled-on-sled testing method. An extreme care was taken to ensure that there is no bottoming-out force for this type of test while adjusting the impact speed of sled. Full frontal tests on FBCC structures were conducted by utilizing five highspeed cameras (HSCs), several accelerometers and a load wall. Excellent correlation was achieved between video tracking and accelerometers results for time histories of displacement and velocity. The standard deviation and coefficient of variance for the energy absorbed were very low suggesting the repeatability of the full frontal tests. The impact histories of FBCC specimens were consistent and in excellent agreement with respect to each other. Post-impact photographs showed the consistent crushing of composite crush cans and breakage of the bumper beam from middle due to the production of tensile stresses stretched caused by straightening of the bumper curvature after hitting the load wall.

This study presents experimental investigations of generic steel Front Bumper and Crush Can (FBCC) assemblies subjected to a 40% offset frontal impact. As automotive industries aim to reduce overall vehicle weight by applying lighter-weight materials to its structures, component-level studies become important. Computer aided models are valuable tools to complement physical testing by assessing the performances of these structures. Due to the lack of studies on component-level tests with FBCCs, a novel component -level test procedure would be useful to aid in CAE correlation. A sled-on-sled testing method was used to perform all the tests reported here. Impact speed was optimized such that there was no bottoming-out force for this type of test. Three high-speed cameras (HSCs), an infrared (IR) thermal camera, and several accelerometers were utilized to study impact performance of the FBCC structures.The results showed that time histories of displacement and velocity from video tracking and accelerometers were in good agreement. 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. Post-impact deformation pattern analysis of the samples showed consistent crush patterns. Heat was generated and dissipated at the tip of the crush can and progressed as the can started to fold.

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.

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.