Bipendulum Impact Test Machine for Aircraft Composite Structures
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Solution Overview
Problem
Existing impact testing machines for aircraft composite structures are inefficient, particularly in simulating horizontal impacts and precise placement of impact damage on large components, due to their bulkiness, inexact impact points, and difficulty in containing reaction forces.
Innovation Solution
A repositionable impact test machine with a bipendulum design, featuring parallel and coplanar vertical shafts, a threaded rod, a carriage, and pivotally engaged links, allowing for adjustable and precise positioning of an impact tip to impart controlled impact damage on test specimens.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If vertical drop towers are used for impact testing, then impact force can be applied, but the equipment becomes bulky and difficult to position, and impact precision deteriorates
Solution Approach 1:
The patent employs a dynamic pendulum mechanism where the impactor is suspended and swings freely under gravity to deliver impact. This dynamic approach replaces the static vertical drop tower, enabling the equipment to be repositioned easily while maintaining impact capability through the pendulum's swing arc.
Solution Approach 2:
The impact testing system is segmented into a movable pendulum assembly that can be independently positioned and adjusted. This segmentation allows the impactor to be separated from the base structure, facilitating easy repositioning and precise placement on large aircraft components without moving the entire testing apparatus.
2Force
If vertical drop towers are used for impact testing, then impact force can be applied, but impact precision deteriorates due to freefalling impactors providing inexact point and shape of impact
Solution Approach 1:
The pendulum's controlled swing arc provides a predictable and repeatable impact trajectory, ensuring precise impact point and shape. The arc-shaped path allows for consistent tangential contact with the specimen surface, improving impact precision compared to uncontrolled freefall.
Solution Approach 2:
The patent adjusts the pendulum release angle and impactor geometry to optimize impact parameters. By controlling the release height and angle, the impact velocity and contact point can be precisely regulated, achieving exact impact location and shape on the test specimen.
3Adaptability or versatility
If spring loaded impact guns are used for impact testing, then horizontal impacting can be achieved, but difficulty arises with containment of reaction force and double impact issues
Solution Approach 1:
The pendulum mechanism inherently balances reaction forces through its counterweight design. The heavy pendulum arm acts as a counterbalance, containing reaction forces during the impact swing and preventing unwanted movement or double impacts. This counterweight effect stabilizes the system during horizontal impacting.
Solution Approach 2:
The dynamic pendulum swing provides a single, controlled impact event rather than the double impact issue seen in spring-loaded systems. The pendulum's momentum carries it through a single arc, ensuring one clean impact without rebound or secondary contact, while still achieving horizontal impacting direction.
4Ease of manufacture
If small coupon pendulum impactors are used for Charpy and Izod testing, then testing can be performed, but effectiveness deteriorates for imparting impact damage on large aircraft components
Solution Approach 1:
The patent designs a universal pendulum impactor system that can test both small coupons and large aircraft components. By adjusting the pendulum length, mass, and release angle, the same basic mechanism effectively imparts impact damage across different specimen sizes and types, from laboratory coupons to full-scale airframe structures.
Solution Approach 2:
The system adjusts key parameters including pendulum mass, length, and release height to match the scale of the test specimen. For large aircraft components, heavier masses and greater release heights are used to generate sufficient impact energy, maintaining reliability and effectiveness across different testing scenarios.
5Ease of manufacture
If small coupon pendulum impactors are used for testing, then Charpy and Izod testing can be performed, but ability to manipulate to specific locations on large airframe structures is lost
Solution Approach 1:
The impactor is designed as a segmented, modular pendulum assembly that can be independently positioned and adjusted. This segmentation allows the impactor to be manipulated to specific locations on large airframe structures while maintaining the proven pendulum testing capability for various specimen types.
Solution Approach 2:
The dynamic pendulum mechanism provides inherent flexibility in positioning and orientation. The pendulum can swing in different arcs and be released from various angles, enabling manipulation to specific locations on large structures while maintaining consistent impact delivery and testing capability.
Data Source
AI summary
A bipendulum impact test machine for imparting impact damage includes a frame of beams where a weighted sled swings from a pair of links extending from a carriage. The carriage and sled are vertically adjustable along a set of vertical shafts of the frame. The sled is permanently horizontally oriented and parallel with the carriage. Interchangeable impact tips are removably and adjustably engaged with the sled. The impact tips have a variety of shapes in order to simulate different impact scenarios. The device is mobile and capable of imparting impact damage to large aircraft parts even in an installed condition.