Automobile Member with Joining Plates for Impact Energy Absorption
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Solution Overview
Problem
Automobile members, such as side sills and frontside members, face challenges in manufacturing yield and impact energy absorption due to complex shapes and axial collapse distortion, leading to spot fractures and decreased energy absorption during collisions.
Innovation Solution
The design incorporates a hat-shaped member with spot-joined flanges and joining plates that are strategically positioned and configured to limit spot fractures, using spot welding, laser welding, or adhesive joining, ensuring the plates are not integrated, allowing independent distortion and maintaining manufacturing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the side sill is designed with a complex hat-shaped cross section to enhance impact energy absorption, then the impact energy absorption amount is improved, but the manufacturing precision and yield deteriorate due to press-forming defects
Solution Approach 1:
The side sill is divided into a first member (hat-shaped panel) and a second member (closing plate or hat-shaped panel) that are joined together. This segmentation allows each member to have a simpler, more manufacturable shape while the combination provides the required impact energy absorption performance through axial collapse distortion.
2Reliability
If the side sill is designed to absorb impact energy through axial collapse distortion, then the collision safety performance is improved, but spot fractures occur at weld locations reducing energy absorption
Solution Approach 1:
Joining plates are strategically placed at specific locations (such as at the web or at predetermined positions along the longitudinal direction) to locally reinforce the structure at critical stress concentration points. This local reinforcement prevents spot fractures at weld locations while allowing axial collapse distortion to proceed smoothly in other regions, maintaining impact energy absorption capability.
3Strength
If joining plates are integrated into the member structure to prevent spot fractures, then spot fracture resistance is improved, but the manufacturing complexity and yield deterioration increase
Solution Approach 1:
The joining plates are designed as separate, independent components that are joined to the first and second members rather than being integrated into a single complex piece. This segmentation simplifies the manufacturing process and allows each component to be produced and assembled separately, reducing overall structural complexity while maintaining spot fracture resistance.
Solution Approach 2:
Joining plates act as intermediary elements between the first member and the second member, providing a bridging function that reinforces the connection and prevents spot fractures at critical locations without requiring the main structural members themselves to be complex or integrated.
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
This configuration enhances impact energy absorption for both axial collapse and three-point bending distortions without reducing manufacturing yield, by limiting spot fractures and optimizing the distribution of melted and solidified portions along the member's length.
Implementation Method 1
The first flange and the closing plate are spot-joined to each other via a plurality of first melted and solidified portions formed along the longitudinal direction
Implementation Method 2
spot welding, laser welding, and the like are mainly used
Implementation Method 3
adhesive joining in which the maximum diameter of a circular bonding portion, an oval bonding portion, an elliptical bonding portion, a C-shaped bonding portion, or a multi-circular bonding portion is 15 mm or smaller
Implementation Method 4
The first joining plate and the inner wall surface of the first wall portion are joined to each other via a second melted and solidified portion. The first joining plate and the inner wall surface of the second member are joined to each other via a third melted and solidified portion
Implementation Method 5
While a vehicle is traveling, deflection caused by elastic deformation of the floor panel is limited by the side sill
Implementation Method 6
it has been ascertained that axial collapse distortion occurs in a side sill at the time of a collision so that impact energy is absorbed by the side sill
Data Source
Figure 1A~1B
Figure 1C
Figure 2A~2B
AI summary
Provided is an automobile member including a hat-shaped first member that has a first flange, a second flange, a first wall portion erected from the first flange, a second wall portion erected from the second flange, and a web connecting the first and second wall portions to each other; a second member that is spot-joined to the first and second flanges; a first joining plate that is joined to inner wall surfaces of the first wall portion and the second member; and a second joining plate that is joined to inner wall surfaces of the second wall portion and the second member.