Ribbed Torsionally Compliant Shaft for Vibration Resistance
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Solution Overview
Problem
Existing torsional compliant transmission shafts are susceptible to harmonic vibrations and resonance, leading to excessive deflections and potential failure due to insufficient transverse stiffness, which cannot meet stricter requirements, especially in aircraft applications where space is compact and vibrations from nearby components are significant.
Innovation Solution
A transmission shaft design featuring a central core with radially extending ribs that increase transverse stiffness while maintaining torsional compliance, with the ribs being functionally isolated from torque transmission to prevent direct torque transfer between the input and output sides, thereby reducing oscillation amplitudes and enhancing lateral stiffness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional compliant shaft design is used, then torsional compliance is achieved, but oscillation amplitude increases
Solution Approach 1:
The ribbed structure segments the rod cross-section into functional zones that independently address torsional compliance and transverse stability. The central core handles torsional deformation while the ribs constrain transverse oscillations, reducing oscillation amplitude by up to 90% compared to traditional solid rod designs.
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 design significantly reduces oscillation amplitudes by up to 90% compared to traditional compliant shafts, ensuring compliance with stringent requirements like the High Level Short Duration (HLSD) curve P (+/−10G n−pk) of the DO160G requirements, minimizing the risk of shaft failure and impact with nearby components.
Implementation Method 1
a torsional compliant section extending therebetween providing the transmission shaft with a torsional stiffness
Implementation Method 2
a radially outer section comprising a plurality ribs which extend radially and longitudinally from an outer periphery of the central core for increasing transverse stiffness of the rod
Data Source
AI summary
A transmission shaft is provided comprising an input side for inputting torque, an output side for outputting torque, and a rod extending in a longitudinal direction between the input side and the output side to transfer torque along the transmission shaft. The rod comprises a first end provided at the input side, a second end provided at the output side and a torsional compliant section extending therebetween providing the transmission shaft with a torsional stiffness. The torsional compliant section comprises a cross-section which extends in the longitudinal direction to define a central core for transmitting torque directly from the first end to the second end and a radially outer section. This section also comprises a plurality ribs which extend radially and longitudinally from an outer periphery of the central core for increasing transverse stiffness of the rod.