Vehicle Frame Subframe Bending Points Impact Energy Dissipation
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Solution Overview
Problem
During frontal vehicle impacts, rigid components such as the engine and drivetrain do not deform to absorb energy, leading to the transmission of impact pulses through the vehicle, potentially increasing the force applied to occupants and risking injury.
Innovation Solution
The vehicle design incorporates a subframe with bending points and crush cans that deform upon impact, dissipating energy and reducing the force transmitted to the passenger compartment by distributing and absorbing the impact energy through multiple energy paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If rigid components (engine, drivetrain) are used to support vehicle loads, then structural strength and stability are improved, but impact energy cannot be absorbed through deformation, causing harmful force transmission to occupants
Solution Approach 1:
The subframe is divided into multiple segments with designated bending points that can deform independently during impact. This segmentation allows different portions of the subframe to absorb energy through controlled deformation while maintaining overall structural integrity and supporting vehicle loads.
Solution Approach 2:
The subframe acts as an intermediary component between the rigid engine/drivetrain components and the vehicle body. It absorbs and dissipates impact energy through its deformable structure, preventing direct force transmission from rigid components to the passenger compartment while still supporting necessary vehicle loads.
2Loss of energy
If the subframe is designed with bending points for energy absorption, then impact energy dissipation is improved, but structural rigidity and load-bearing capacity are reduced
Solution Approach 1:
The subframe employs local quality by having specific bending points with reduced rigidity at predetermined locations, while the rest of the structure maintains full structural rigidity. This allows energy absorption to occur locally at the bending points during impact, while the overall subframe retains sufficient strength to support vehicle loads during normal operation.
Solution Approach 2:
The subframe design incorporates parameter changes in material properties or cross-sectional geometry at the bending points, creating zones with different mechanical characteristics. These modified zones enable controlled deformation and energy absorption, while other portions of the subframe maintain original parameters for structural strength and load-bearing capacity.
3Loss of energy
If multiple energy paths are created through bumper connections to rails and prongs, then impact energy distribution is improved, but device complexity increases
Solution Approach 1:
The upper rail structure with its base portion and multiple prongs serves multiple functions: it provides structural support, creates multiple energy absorption paths during impact, and connects various vehicle components (bumper, subframe). This multi-functionality achieves complex energy distribution patterns without proportionally increasing device complexity, as the same structural elements perform multiple roles.
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 design effectively reduces the peak force applied to vehicle occupants during frontal impacts by absorbing and distributing impact energy, thereby minimizing the risk of injury and enhancing safety compliance with regulatory standards.
Implementation Method 1
The subframe may include a bending point between the body and the bottom prong designed to bend downward in response to a vehicle frontal impact. The top prong may have a bending point designed to bend upward in response to a front impact.
Implementation Method 2
front structural components of the vehicle may deform to absorb energy. These rigid components may not deform to absorb energy. Thus, these rigid components may transmit a pulse through the rest of the vehicle during a frontal impact.
Data Source
AI summary
A vehicle includes a body having a first rail and an upper rail spaced from the first rail. The upper rail has a base portion and a top prong and a bottom prong each extending from the base portion. The vehicle includes a bumper connected to the first rail and to the top prong, and a subframe connected to the bottom prong.