Flexible Pad Ridges for Curved Shield Impact Protection
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Solution Overview
Problem
Existing impact protection systems for curved objects, such as helmets and limb protectors, face challenges in conforming flexible pads to curved surfaces without compromising their deformation characteristics and in maintaining effective impact attenuation over time.
Innovation Solution
The use of composite flexible pads made from rate-sensitive materials, including dilatant polyurethane foams, which are designed with spacing and support ridges that can be angled and flex to maintain alignment and absorb impact forces effectively, even when curved, and can be easily integrated into shield systems for enhanced protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a flat pad is deformed to conform to a curved shield surface, then the pad can be integrated into curved shield systems, but the deformation characteristics and alignment of the pad may be compromised
Solution Approach 1:
The pad is designed with pre-curved surfaces that match the curvature of the shield, allowing the pad to conform to curved surfaces without requiring additional deformation that would compromise ridge alignment. The curved geometry is built into the pad structure during manufacturing.
Solution Approach 2:
The pad incorporates rate-sensitive materials whose mechanical properties change based on deformation rate. During normal wear, the material remains relatively rigid to maintain ridge alignment, but during impact, it becomes more compliant to absorb energy while maintaining structural integrity.
2Loss of energy
If compressible materials are used to line shields, then impact energy can be absorbed, but the acceleration experienced by the shielded object may not be sufficiently reduced
Solution Approach 1:
The pad combines rate-sensitive polymeric materials with traditional foam materials to create a composite structure. The rate-sensitive component provides progressive energy absorption that increases with deformation rate, while the foam component provides consistent compression to reduce acceleration, achieving both energy absorption and acceleration reduction simultaneously.
Solution Approach 2:
The pad uses materials with dynamic mechanical properties that change during impact. The rate-sensitive material transitions from a rigid state during normal use to a more compliant state during high-rate deformation, allowing the pad to adapt its energy absorption characteristics to the severity of the impact while maintaining ridge alignment throughout the event.
3Manufacturing precision
If ridges are added to maintain alignment, then ridge alignment with pad surface is improved, but strain on support ridges increases when curved
Solution Approach 1:
The pad features localized reinforcement zones at critical support ridge locations where curvature-induced strain is highest. These reinforced zones provide additional structural support specifically where needed, allowing the ridges to maintain alignment without experiencing excessive strain that would compromise their strength.
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
These pads provide improved impact attenuation by maintaining the alignment of ridges with the pad surface, reducing strain on support ridges, and allowing for effective deformation to absorb impact forces, thus enhancing the protection of curved objects without compromising their structural integrity or ease of use.
Implementation Method 1
a rate-sensitive material is defined as a non-Newtonian material (i.e. having a non-Newtonian stress-strain profile) that exhibits a resistive load under deformation which increases with the rate of deformation. Rate-sensitive materials, which include shear thickening and dilatant materials, are capable of decelerating impact associated energies.
Implementation Method 2
Suitable materials include elastic materials such as polymeric elastomers and foam materials, for example polymeric foams
Implementation Method 3
These act to reduce the acceleration experienced by the shielded object as a result of an impact. For example, compression of a helmet liner may absorb some energy that would otherwise be transmitted to the head of a wearer.
Data Source
AI summary
A shield system for protecting a curved object is described. The system comprises at least one flexible pad. The at least one flexible pad comprises a spacing ridge (7) projecting at an angle from a first major surface (3) of the pad for providing a spacing between the first major surface and a support ridge (9) projecting from the first major surface and extending transverse to the spacing ridge. The support ridge comprises a flexure region (11) adapted to unbend in the event that the pad is curved about an axis aligned with the spacing ridge to inhibit strain in the support ridge from causing deflection of the spacing ridge.