Bumper Beam with Variable Bending Rigidity for Small Overlap Collision
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Solution Overview
Problem
Conventional vehicle front body structures experience buckling of the bumper beam during small overlap collisions, which hinders the effective transfer of collision loads to the crash can and front frame, compromising safety by reducing the ability to absorb energy through deformation.
Innovation Solution
A vehicle front body structure design featuring a bumper beam with a crash can fixed section and an extending section, where the bending rigidity is highest at the inner end portion of the crash can fixed section and gradually reduces outward, combined with a U-shaped reinforcing member and step sections on the surfaces, to distribute collision loads efficiently and prevent buckling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the bumper beam has uniform bending rigidity along its length, then the structure is simple to manufacture, but the inner end portion of the crash can fixed section is most likely to buckle during small overlap collision due to highest bending moment
Solution Approach 1:
The bumper beam is designed with non-uniform bending rigidity distribution, where the bending rigidity is specifically increased at the inner end portion of the crash can fixed section to match the highest bending moment location. This local reinforcement prevents buckling at the critical position while maintaining simpler structure in other regions, resolving the contradiction between buckling resistance and structural complexity.
2Strength
If a reinforcing member is accommodated in the end portion of the hollow bumper, then the overall strength is improved, but the reinforcing member turns in the vehicle longitudinal direction under collision load, causing local stress concentration that promotes buckling at the inner end portion
Solution Approach 1:
The reinforcing member is designed with variable cross-sectional area along its length, with the largest cross-sectional area positioned at the inner end portion of the crash can fixed section. This local reinforcement strategy strengthens the bumper beam at the critical buckling location while allowing the reinforcing member to accommodate collision loads more effectively, preventing the turning motion that causes stress concentration and buckling.
Data Source
AI summary
A vehicle front body structure is provided for reliably transferring a collision load to a crash can and a front frame by preventing a bumper beam from buckling during a small overlap collision. Bending rigidity of the bumper beam in a vehicle width direction is such that 1) a bending moment generated on the bumper beam when a collision load in a direction toward a vehicle rear side is applied to an extending section, which extends outward in the vehicle width direction from a crash can fixed section, is the highest in a vehicle width direction inner end portion of the crash can fixed section on a side where the collision load is applied, and 2) the bending moment is continuously reduced as a distance from the vehicle width direction inner end portion in the vehicle width direction increases.