Elastic Perforated-Disk Fastening for Cyclic Vibration Loads
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Solution Overview
Problem
Conventional screw connections for fastening workpieces in non-damped regions of vehicles, such as rail vehicle chassis, introduce local stress peaks and are unable to withstand cyclic loadings, leading to material damage and failure.
Innovation Solution
A device featuring a screw or threaded rod with at least two elastically deformable perforated disks, each with a through-bore for the screw, which are designed to absorb and distribute axial preload forces, reducing stress concentrations and enhancing vibration damping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional screw connections are used to fasten workpieces, then the workpiece can be securely attached, but local stress peaks are introduced into the plastics component leading to material damage and crack formation under cyclic loading
Solution Approach 1:
The fastening system is segmented into multiple components: the screw connection, the workpiece, and at least two elastically deformable perforated disks with through-bores. These disks are arranged along the screw axis between the screw head and the workpiece, distributing the clamping force across multiple discrete elements rather than concentrating it at a single interface.
Solution Approach 2:
The elastically deformable perforated disks serve as pre-installed cushioning elements that absorb and distribute stress before it reaches the workpiece. Their elastic deformability allows them to accommodate load variations and prevent stress peaks from being transmitted directly to the plastics component, thereby preventing material damage and crack formation under cyclic loading conditions.
2Ease of manufacture
If workpieces made of plastics with low fatigue strengths are used in non-damped regions, then manufacturing flexibility is improved, but the workpieces cannot withstand high-cyclic vibrations and impacts
Solution Approach 1:
The elastically deformable perforated disks act as intermediary elements between the rigid screw connection and the plastics workpiece. These intermediaries absorb mechanical stresses and vibrations, protecting the low-fatigue-strength plastics material from damage while allowing the use of such materials for manufacturing flexibility benefits.
3Stability of the object's composition
If rigid fastening systems are used to ensure stable attachment, then positioning precision is improved, but vibration and impacts are transmitted directly to the workpiece causing damage
Solution Approach 1:
The system changes the mechanical parameters of the fastening connection by introducing elastically deformable elements. This transforms the rigid connection into a compliant system that maintains stable attachment while modifying the transmission characteristics of vibrations and impacts, reducing harmful factor transmission to the workpiece.
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 solution enables the use of materials with low fatigue strengths, such as plastics, in high-cyclic loading conditions by distributing forces evenly and reducing local stress peaks, thereby increasing the service life and operational capability of workpieces.
Implementation Method 1
at least two elastically deformable perforated disks which each have a through-bore for passing the screw or the threaded rod through... the first perforated disk can elastically deform in the radial direction to an at least predefined extent
Implementation Method 2
Device for vibration-damped fastening of a workpiece... are exposed to non-damped impacts, vibrations or oscillations with a high number of cycles
Data Source
AI summary
A device releasably fastens to a workpiece. The device contains a screw and the workpiece is fastened by use of a through-bore for passing the screw. The device contains elastically deformable perforated plates, which each have a through-bore for passing the screw through and thus can be aligned with the workpiece and can be placed against the workpiece such that the screw can be passed through the through-bore of the workpiece and through the through-bore of the first perforated plate and through the through-bore of the second perforated plate. The workpiece, around the first perforated plate, has a predefined free space in the radial direction relative to the axis of the through-bore through the first perforated plate in the predefined, intended assembly position and in a relaxed state of the first perforated plate, such that the first perforated plate can deform elastically in the radial direction to a predefined extent.