Flexible Hinge Windshield Assembly for Bird-Strike Load Absorption
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Solution Overview
Problem
Existing windshield mounting assemblies, particularly those for helicopters, face challenges in absorbing impact loads from foreign objects like bird strikes due to high strain rates and sensitivity to notches, holes, and cold temperatures, while also being heavy and complex to integrate, with limited adaptability to geometric constraints.
Innovation Solution
A windshield assembly featuring a flexible plate-type element with a picture frame-like shape that connects the windshield to the vehicle frame, allowing it to pivot and absorb impact loads, reducing stress on the windshield and frame, and using adhesive layers for bonding to minimize weight and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a conventional multilayer windshield is used for foreign object impact protection, then the windshield can withstand bird strikes, but the weight and structural complexity increase significantly
Solution Approach 1:
The patent changes the material parameter from conventional multilayer glass to polycarbonate, which provides comparable impact resistance but with reduced weight. The polycarbonate material inherently possesses high toughness and energy absorption capabilities that satisfy the bird strike protection requirement while being lighter than traditional multilayer constructions.
Solution Approach 2:
The patent employs a composite structure combining polycarbonate material with specific geometric features (curvature, thickness variations) to achieve impact protection. This composite approach integrates material selection with structural design to provide the necessary strength without the full weight penalty of conventional multilayer systems.
2Weight of moving object
If a polycarbonate windshield is used to reduce weight, then the weight decreases and geometric freedom increases, but the material becomes sensitive to notches, holes, and cold temperatures
Solution Approach 1:
The patent applies local quality by varying the thickness of the polycarbonate windshield in different regions. Areas more susceptible to stress concentration (near mounting points, curvature changes) are given increased thickness or optimized geometry to compensate for the material's sensitivity to notches and holes, while other areas maintain thinner sections for weight savings.
Solution Approach 2:
The patent incorporates design features that preemptively address the material's weaknesses. By carefully controlling the curvature radius and thickness distribution before installation, the design cushions against the inherent sensitivity of polycarbonate to stress concentrators and cold temperatures, preventing failure modes before they can occur during operation.
3Force
If a mounting frame with fasteners is used to transfer loads, then the load transfer capability increases, but the device complexity and weight increase
Solution Approach 1:
The patent merges the windshield structure with the mounting structure by integrating attachment features directly into the polycarbonate windshield itself. This eliminates the need for a separate mounting frame, as the windshield incorporates its own mounting elements, thereby reducing device complexity while maintaining load transfer capability.
Solution Approach 2:
The patent extracts the mounting frame from the overall assembly, eliminating this separate component entirely. The load transfer function is achieved through integrated features on the polycarbonate windshield itself, removing the need for additional fasteners and mounting hardware that would increase complexity and weight.
4Speed
If the windshield curvature is increased for aerodynamic performance, then the aerodynamic efficiency improves, but the stress concentration during impact increases
Solution Approach 1:
The patent optimizes the curvature parameters of the polycarbonate windshield to find an optimal balance. By carefully selecting the radius of curvature and its distribution across the windshield surface, the design achieves good aerodynamic performance while avoiding excessive stress concentration that would compromise impact strength. The parameter optimization accounts for the specific properties of polycarbonate material.
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 flexible element effectively reduces the risk of windshield breakage during impacts by absorbing energy and transferring loads, maintaining visibility, and simplifying integration while being lighter and more compact than conventional designs.
Implementation Method 1
The flexible element is attached to the windshield and connects the windshield to the vehicle frame for at least partially absorbing loads resulting from an impact on the windshield
Implementation Method 2
using adhesive layers for bonding to minimize weight and complexity
Data Source
AI summary
A vehicle with a vehicle frame and a windshield assembly that is mounted to the vehicle frame and closes an associated opening provided in the vehicle frame. The windshield assembly comprises at least one flexible element and at least one windshield. The at least one flexible element connects the at least one windshield to the vehicle frame for at least partially absorbing loads resulting from an impact on the at least one windshield. The at least one flexible element connects the at least one windshield to the vehicle frame such that the at least one windshield pivots relative to the vehicle frame by means of the at least one flexible element upon occurrence of an impact on the at least one windshield such that the at least one flexible element defines a hinge element.