Heavy Goods Vehicle Longitudinal Member with Segmented Impact Absorption
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Solution Overview
Problem
Conventional longitudinal members for heavy goods vehicles are inadequate in protecting occupants during front impacts, as they either lead to deformation of the vehicle compartment or insufficient energy absorption, potentially causing injuries.
Innovation Solution
A longitudinal member with a front part made of press-hardened steel having a higher product of wall thickness and yield strength than the rear part, designed to remain undeformed during impacts, allowing energy absorption by the rear part away from the occupant space, thus protecting the compartment where passengers are seated.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a deformable part is arranged at the front of the longitudinal member to absorb impact energy, then energy absorption is improved, but the vehicle compartment where occupants are seated is deformed causing injuries
Solution Approach 1:
The longitudinal member is divided into two distinct parts: a front part made of press-hardened steel with high yield strength designed to remain undeformed, and a rear part made of ductile material designed to be crushed and buckle. This segmentation allows each part to perform its specific function - the front part protects the occupant compartment while the rear part absorbs impact energy through deformation.
Solution Approach 2:
Different materials and mechanical properties are assigned to different parts of the longitudinal member. The front part uses press-hardened steel with high yield strength (1300-1600 MPa) to maintain structural integrity and protect the occupant space, while the rear part uses ductile material with lower yield strength to absorb energy through controlled deformation. This local differentiation of material properties enables simultaneous protection and energy absorption.
2Loss of energy
If the whole longitudinal member is deformed to distribute energy absorption, then deformation of occupant space is reduced, but the occupant space still gets deformed causing injuries
Solution Approach 1:
The longitudinal member is segmented into a front part with high yield strength that remains undeformed and a rear part that absorbs energy through deformation. This segmentation prevents the deformation from propagating to the occupant compartment while still achieving adequate energy absorption through the rear part's controlled buckling and crushing.
3Object-affected harmful factors
If a high strength material is used for the front part to prevent deformation, then protection of occupant space is improved, but energy absorption capability is reduced
Solution Approach 1:
The longitudinal member is divided into a front part made of press-hardened steel with high yield strength (1300-1600 MPa) that remains undeformed to protect the occupant compartment, and a rear part made of ductile material that absorbs the majority of impact energy through controlled deformation and buckling. This segmentation ensures both protection and adequate energy absorption.
Solution Approach 2:
The front part uses press-hardened steel with high yield strength to maintain structural integrity and prevent deformation of the occupant space, while the rear part uses ductile material with lower yield strength optimized for energy absorption through plastic deformation. This local differentiation ensures each part performs its specific function effectively.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution effectively absorbs impact energy by deforming the rear part while keeping the front part substantially undeformed, enhancing occupant safety by directing energy absorption away from the passenger compartment.
Implementation Method 1
the product of the wall thickness of the front part by the yield strength of the material of the front part is greater than the product of the wall thickness of the rear part by the yield strength of the material of the rear part
Implementation Method 2
energy absorption of an impact by deformation of the rear part of the longitudinal member
Implementation Method 3
the impact is applied on the deformable part, while the undeformable part extends away from the point of impact
Data Source
AI summary
A longitudinal member is provided. The longitudinal member includes a front end provided with a hinge element for attaching the longitudinal member in an articulated manner to a heavy goods vehicle body, and a rear end including an attachment element for attaching the longitudinal member in a non-permanent manner to the heavy goods vehicle body. The longitudinal member includes a front part extending from the front end to an intermediate area of the longitudinal member and a rear part extending from the intermediate area to the rear end of the longitudinal member. The product (PF) of the wall thickness (tF) of the front part by the yield strength (YsF) of the material of the front part is greater than the product (PR) of the wall thickness (tR) of the rear part by the yield strength (YsR) of the material of the rear part.