Rippled Hood Cushion for Kinetic Energy Absorption
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Solution Overview
Problem
Conventional vehicle hood structures face challenges in energy absorption due to proximity to rigid engine components, limiting their ability to absorb kinetic energy during impacts and increasing stopping distance.
Innovation Solution
An energy-absorbing hood assembly with a rippled cushion support is designed, featuring sinusoidal profiles and multiple layers that absorb and attenuate kinetic energy through controlled deformation and failure, enhancing crashworthiness and reducing dash panel intrusion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the hood is made deformable to absorb energy during impact, then the hood's ability to absorb kinetic energy is improved, but the hood's proximity to rigid engine components limits this deformability and energy absorption capability
Solution Approach 1:
The patent applies a sinusoidal (curved) profile to the inner surface of the hood panel instead of a flat surface. This curvature creates a rippled cushion support structure that enables controlled deformation during impact, allowing the hood to absorb kinetic energy through the progressive collapse of the sinusoidal waves while maintaining structural integrity and aesthetic appearance.
Solution Approach 2:
The hood assembly combines multiple materials and structures: an outer hood panel, an inner layer with sinusoidal profile, and hat-section reinforcements. This composite structure allows the hood to exhibit both stiffness for normal operation and controlled deformability for energy absorption during impact, resolving the contradiction between structural integrity and energy absorption capability.
2Loss of energy
If additional clearance is provided between the hood and engine compartment, then the hood's ability to absorb energy through deformation is improved, but driver visibility, aerodynamics, and aesthetic appeal are compromised
Solution Approach 1:
The sinusoidal profile creates a curved, rippled structure between the hood outer panel and engine compartment. This curvature allows the hood to maintain minimal clearance to under-hood components while still providing sufficient deformation space for energy absorption, as the rippled structure can collapse progressively without requiring large overall clearance.
Solution Approach 2:
The patent modifies the geometric parameters of the hood structure by introducing a sinusoidal profile with specific amplitude and wavelength characteristics. This parameter change enables the hood to achieve enhanced energy absorption capability within the constrained space, allowing controlled deformation without increasing overall clearance requirements.
3Strength
If the hood is designed with high bending stiffness for normal operation, then structural rigidity and resistance to flutter at high speeds are improved, but the hood's deformability and ability to absorb energy during impact are reduced
Solution Approach 1:
The hood structure is segmented into distinct functional zones: hat-section reinforcements provide stiffness for normal operation, while the sinusoidal-profiled inner layer provides controlled deformability for energy absorption. This segmentation allows different parts of the hood to serve different functions simultaneously, resolving the contradiction between stiffness and deformability.
Solution Approach 2:
The hood structure transitions from a static, rigid configuration during normal operation to a dynamic, deformable configuration during impact. The sinusoidal profile enables this dynamic response by allowing the structure to progressively collapse through wave propagation, absorbing energy while maintaining rigidity when undisturbed.
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 design improves kinetic energy absorption, reduces stopping distance, and maintains structural integrity and aesthetic appeal by providing a compliant surface and high bending stiffness, while minimizing contact with under-hood components during impacts.
Implementation Method 1
The inner layer is attached, secured, or adhered to the upper layer to thereby position or orient the sinusoidal profile to extend from the forward end towards the rearward end of the vehicle structure... The first amplitude and wavelength are each configured to provide a first predetermined level of absorption and attenuation of kinetic energy imparted to the hood assembly by an object upon impact therebetween
Data Source
AI summary
An energy-absorbing hood assembly for a vehicle includes an inner layer operatively secured to an upper layer having a first interface surface. The inner layer has opposing first and second surfaces defining a sinusoidal profile that is oriented to extend from the forward end of the vehicle towards the rearward end of the vehicle. The sinusoidal profile includes varying amplitudes and wavelengths along different regions of the hood assembly. The amplitudes and wavelengths are individually configured to provide regionally distinct predetermined levels of absorption and attenuation of kinetic energy imparted to the hood assembly by an object upon impact therebetween. Preferably, the hood assembly also includes a lower layer having a second interface surface; wherein the inner layer has a plurality of bonding surfaces attached to the first and second interface surfaces to thereby define a plurality of laterally oriented channels.