Serpentine Millipede Bar for Compact Stress Wave Propagation
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Solution Overview
Problem
Current mechanical waveguides used in construction engineering and material testing are often excessively long, occupying significant space and incurring high capital costs, making them impractical for compact applications.
Innovation Solution
The millipede bar design features multiple rod segments of rectangular cross-section joined at alternate ends with 180° bend junctions in a serpentine fashion, allowing for efficient propagation of long-duration longitudinal stress waves in a compact footprint.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If long straight bars are used to propagate stress pulses, then the propagation distance is increased, but the occupied space and capital cost increase significantly
Solution Approach 1:
The patent applies dimensionality change by transforming the straight linear arrangement into a serpentine configuration that utilizes two-dimensional space. Multiple rod segments are arranged in a winding path with bend junctions, allowing the stress pulse to travel a longer effective distance while occupying a smaller footprint area. This converts a one-dimensional length problem into a two-dimensional space utilization solution.
Solution Approach 2:
The long bar is segmented into multiple rod segments connected by bend junctions. Each segment can be independently positioned and connected, allowing the system to achieve long propagation distance through compact folding rather than requiring a single continuous straight bar. This segmentation enables the waveguide to be packaged in a smaller space while maintaining the acoustic length needed for stress pulse propagation.
2Length of moving object
If long straight bars are used to propagate stress pulses, then the propagation distance is increased, but the capital cost increases prohibitively
Solution Approach 1:
By utilizing spatial folding through serpentine configuration, the patent reduces the amount of material needed compared to a straight bar of equivalent propagation distance. The dimensionality change allows the same acoustic length to be achieved with less total bar length, directly reducing material costs and capital investment while maintaining the required stress pulse propagation capability.
3Area of stationary object
If rod segments are joined with bend junctions in serpentine fashion, then the occupied space is reduced, but the wave propagation distortion may increase
Solution Approach 1:
The patent carefully designs the bend junctions to minimize unwanted vibrations and mode conversions that could distort the stress pulse. By controlling the geometry and stiffness of the bend regions, the design ensures that longitudinal waves pass through with minimal energy loss to transverse vibrations, maintaining wave propagation fidelity despite the serpentine configuration.
Solution Approach 2:
The patent optimizes geometric parameters of the bend junctions, such as the radius of curvature and transition angles, to ensure smooth stress wave transmission. By carefully selecting these parameters, the design minimizes reflections and distortions at the junctions, allowing the serpentine configuration to maintain high wave propagation fidelity while achieving compact space utilization.
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
This design enables the propagation of long-duration stress pulses with minimal distortion over a long distance, reducing the overall length and cost of waveguides while maintaining equivalent acoustic length, suitable for various engineering applications.
Implementation Method 1
Mechanical waveguides are often used in the fields of construction engineering (e.g., pile drivers, jack hammers, deep-drilling equipment) and material testing [e.g., split Hopkinson pressure bar (SHPB) or Kolsky bar, high frequency fatigue equipment]. These waveguides are long metal rods designed to transfer longitudinal stress pulses with minimal distortion.
Data Source
AI summary
The present disclosure presents pressure bar testing systems, methods, and apparatuses. One such apparatus comprises a millipede bar having a plurality of bar segments joined at alternate ends with 180 degree bend junctions in a serpentine pattern forming a continuous path for wave propagation, wherein the plurality of bar segments comprise a central primary bar surrounded by two groupings of secondary bars, wherein the central primary bar has an impact-end and an opposite end that connects to adjacent secondary bars with 180 degree bend junctions, wherein the adjacent secondary bars belong to the two groupings of secondary bars.