Inverted Hat-Shaped Force Attenuator Mass Optimization

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Solution Overview

Problem

Conventional thermoformed energy absorbers face challenges in maintaining accurate trim registration and minimizing the size of the periphery flange during manufacturing, which affects their mass and energy absorption efficiency in vehicle applications.

Innovation Solution

A force-attenuating system comprising inverted hat-shaped units with converging sidewalls, sound-deadening structures, and apertures, where the units are thermoformed with a thicker sidewall and adhered to the interior surface through the floor, reducing the need for a large flange and allowing for a more rigid and mass-efficient design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional thermoformed energy absorbers use separate forming and trimming operations, then manufacturing is simplified, but trim registration accuracy deteriorates with variation of several millimeters

Engineering Contradiction:

Improvemanufacturing process simplicityVSAvoidtrim registration accuracy

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent combines the forming and trimming operations into a single integrated process. The thermoforming tooling includes integrated trim features that are formed simultaneously with the energy absorber body, eliminating the need for separate trimming operations and ensuring precise registration between the trim and formed features.

Inventive Principle:

Principle #5Merging (Combining)

2Ease of manufacture

If a large flange is provided for adhesive attachment, then attachment surface area is sufficient, but vehicle mass increases

Engineering Contradiction:

Improveattachment surface areaVSAvoidvehicle mass

Core Design Contradiction:

Ease of manufactureVSWeight of moving object

Solution Approach 1:

The patent inverts the conventional design by placing the adhesive attachment surface on the interior surface of the energy absorber rather than on an exterior flange. This allows the adhesive to bond to the mating component from the inside, eliminating the need for a large external flange and reducing overall mass while maintaining sufficient attachment area.

Inventive Principle:

Principle #13The other way round (Inversion)

3Weight of moving object

If the flange dimension is reduced to minimize mass, then vehicle mass decreases, but adequate adhesive land area becomes difficult to maintain

Engineering Contradiction:

Improvevehicle massVSAvoidadhesive land area consistency

Core Design Contradiction:

Weight of moving objectVSEase of manufacture

Solution Approach 1:

The patent moves the adhesive attachment surface from a two-dimensional external flange to the internal surface geometry of the energy absorber. By utilizing the interior surface area and potentially creating multi-layer or multi-zone adhesive regions, sufficient bond area is achieved without requiring a large external footprint, thus reducing mass while maintaining attachment consistency.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 reduces the mass of the energy absorber by up to 30% and enhances energy absorption by distributing loads over a larger surface area, providing a stiffer structure with a smaller footprint and improved force attenuation characteristics.

Implementation Method 1

force-attenuating units with sidewalls extending inwardly convergingly away from the ceiling... energy absorption by distributing loads over a larger surface area

Methodology Applied

Scientific EffectEnergy absorption: Deformation

Implementation Method 2

upper sound-deadening structures positioned between the ceiling... and the exterior surface... lower sound-deadening structures positioned between the floor... and the interior surface

Methodology Applied

Scientific EffectSound absorption: Acoustic Absorption

Implementation Method 3

lower means for adhering at least one force-attenuating unit to the interior surface

Methodology Applied

Scientific EffectAdhesion: Adhesive

Data Source

PatentUS10788091B2Mass-optimized force attenuation system and method

Publication Date: 2020.09.29 OAKWOOD ENERGY MANAGEMENT INC

AI summary

A force-attenuating system that is interposed between an exterior surface and an interior surface, either or both of which may be subjected to percussive forces. The system has a ceiling that is positioned proximate the exterior surface and one or more inverted hat-shaped force-attenuating units with sidewalls extending inwardly convergingly away from the ceiling. Some of the units have a floor that is positioned proximate the interior surface. Optionally the force-attenuating units may be configured as clover-leaf structures with a central region and hemi-pear-shaped lobes extending therefrom. Within the lobes is a floor that is positioned proximate the interior surface. The force-attenuating system may be deployed in an automotive or non-automotive environment.