Vehicle Hood Structure Character Line Intersection for Pedestrian Protection
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Solution Overview
Problem
Existing vehicle hood structures face issues with deformation stiffness in the front-rear direction during collisions, leading to reduced pedestrian protection performance due to excessive bending deformation and increased collision energy absorption, which degrades the HIC value and increases the likelihood of under-hood component contact.
Innovation Solution
A vehicle hood structure featuring a hood inner panel with annular outer surfaces and beads extending in the vehicle width direction, coupled with a hood outer panel having character lines that intersect the central line within a specific region, enhancing stress propagation and deformation resistance to achieve stable bending deformation and improved pedestrian protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the height of the crush bead is increased to reduce deformation stiffness in the vehicle front-rear direction, then the vehicle hood structure becomes easier to bend, but the bending deformation occurs more easily than required from the crush bead as a starting point during pedestrian collision, causing rapid reduction of acceleration after the first peak and degrading the HIC value
Solution Approach 1:
The patent applies local quality by providing beads that extend in the vehicle width direction at specific locations on the hood inner panel, while the character lines on the hood outer panel create localized deformation zones. This localized structural modification allows the hood to maintain high deformation stiffness in the front-rear direction overall, while enabling controlled bending deformation at specific locations during pedestrian collision, preventing premature deformation from the crush bead and maintaining acceleration characteristics for satisfactory HIC values.
Solution Approach 2:
The patent transitions from considering only front-rear direction deformation (one dimension) to incorporating width direction deformation control (second dimension). The beads extending in the vehicle width direction and character lines intersecting the central line create a two-dimensional deformation control system, allowing the hood to resist unwanted bending while enabling controlled deformation where needed during collisions.
2Ease of operation
If beads extend in the vehicle width direction to facilitate bending deformation, then the vehicle hood structure is likely to undergo bending deformation, but when the pedestrian head collides with the central portion, the acceleration after the first peak is significantly reduced, enlarging the stroke and increasing the second acceleration peak, which degrades the HIC value
Solution Approach 1:
The character lines are positioned to intersect the central line within a specific distance from the center point, creating localized deformation resistance exactly where needed (at the central portion). This localized reinforcement prevents the harmful acceleration reduction and stroke enlargement that would otherwise occur during central pedestrian head collisions, while still allowing bending deformation capability in other regions.
Solution Approach 2:
The character lines create preliminary resistance to bending deformation at the central portion before the collision fully develops. This pre-positioned structural feature prevents the acceleration from being significantly reduced after the first peak, counteracting the harmful effect of excessive bending deformation before it can occur during pedestrian head collision at the central area.
3Strength
If the vehicle hood structure is designed for front collision performance with angular bending deformation, then the center of the hood structure rises and bends into an angular shape to prevent entrance into the vehicle, but the deformation stiffness in the vehicle front-rear direction becomes high, making the hood structure not easily bent
Solution Approach 1:
The patent segments the hood structure into multiple functional elements: crush beads for energy absorption, beads extending in the width direction for lateral stability, and character lines for localized deformation control. This segmentation allows each element to perform its specific function - maintaining high front-rear deformation stiffness for front collision performance while enabling controlled bending through the coordinated action of multiple segmented features.
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 proposed structure ensures a high first acceleration peak while reducing the second acceleration peak, increasing collision energy absorption and maintaining a satisfactory HIC value, thus enhancing pedestrian protection performance.
Implementation Method 1
the amount of absorption of collision energy is reduced, and accordingly, the HIC value is degraded
Implementation Method 2
enhancing stress propagation and deformation resistance to achieve stable bending deformation
Data Source
AI summary
A vehicle hood structure includes a hood outer panel and a hood inner panel. The hood outer panel includes at least one character line extending substantially in a vehicle front-rear direction. The character line intersects a central line that extends in a vehicle width direction and that passes through a central point where a center of the hood outer panel in the vehicle front-rear direction and a center of the hood outer panel in the vehicle width direction are superposed on each other. The character line intersects the central line at an intersection point positioned within a region extending from the central point by 300 mm or less in the vehicle width direction.