Collet-Chuck Mounting for Faster Uniaxial Specimen Testing
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Solution Overview
Problem
Current fatigue cracking tests for asphalt concrete mixes are lengthy, cumbersome, and expensive, with challenges including extensive material requirements, difficulty in meeting air void targets, high equipment costs, and excessive sample preparation time due to premature failures from improper sample cutting and gluing.
Innovation Solution
A collet-chuck system is used to rapidly mount and hold specimens in place for uniaxial testing, eliminating the need for glued endplates and allowing for rapid specimen replacement, thereby simplifying and accelerating the testing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional glued endplate mounting method is used, then specimen can be securely held for testing, but sample preparation time increases and testing becomes cumbersome
Solution Approach 1:
The patent removes the endplates and adhesive components from the traditional mounting system, replacing them with a collet-chuck mechanism that grips the specimen directly. This extraction of unnecessary components eliminates the time-consuming gluing process while maintaining secure specimen holding through the collet's mechanical grip.
Solution Approach 2:
The patent replaces the chemical bonding mechanism (adhesive) with a mechanical gripping system (collet-chuck). The collet-chuck uses radial compression to secure the specimen, substituting the chemical-adhesive-based mounting system with a purely mechanical one that is faster and more reliable.
2Manufacturing precision
If precise parallel cutting of specimen ends is performed, then proper gluing can be achieved, but manufacturing complexity and time increase
Solution Approach 1:
Instead of preparing the specimen ends to fit a fixed mounting system (requiring precise parallel cutting), the mounting system adapts to the specimen. The collet-chuck mechanism can accommodate slight variations in specimen geometry by adjusting its grip, inverting the traditional approach where the specimen must conform to rigid mounting requirements.
Solution Approach 2:
The collet-chuck mechanism allows for parameter adjustments in gripping force and positioning, enabling secure mounting without requiring strict geometric precision of the specimen ends. This flexibility in mounting parameters eliminates the need for complex precision cutting operations.
3Strength
If glued endplates are used for mounting, then specimen can be held firmly, but device complexity and testing duration increase
Solution Approach 1:
The collet-chuck mechanism is divided into modular components (collet, chuck body, adjustment mechanism) that can be independently manufactured and assembled. This segmentation simplifies the overall device complexity compared to the integrated endplate-adhesive system, while maintaining mounting firmness through the segmented gripping action.
4Reliability
If traditional mounting procedures are followed, then complete specimen securing is achieved, but productivity decreases due to excessive preparation time
Solution Approach 1:
The collet-chuck mechanism is pre-positioned and ready to grip the specimen immediately upon insertion, eliminating the sequential steps of placing endplates, applying adhesive, and allowing curing time. This preliminary preparation of the mounting system enables immediate specimen securing, dramatically improving productivity while maintaining reliable mounting.
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 collet-chuck system reduces overall testing time while maintaining high-quality test results by enabling efficient specimen mounting and strain measurement, reducing the need for on-specimen sensors and minimizing sample preparation time.
Implementation Method 1
The collet-chuck system is adapted to apply a radial compressive force to the solid specimen to secure the specimen in place
Data Source
AI summary
The disclosure relates to apparatus and methods for uniaxial testing of a solid specimen, such as an asphalt or asphalt concrete specimen. The apparatus provides a simplified and accelerated procedure for mounting and testing asphalt mixture samples and other solid specimens under uniaxial tension and/or compression, in particular to measure corresponding uniaxial strain and/or fatigue in the specimen. The apparatus incorporates two opposing collet-chuck elements to rapidly mount and fixedly hold a solid specimen in place in a loading system to apply uniaxial loads. The disclosure further relates to an off-specimen means for measuring strain in a specimen using optical imaging in which successive time series images of a specimen during uniaxial loading can be analyzed to determine displacements and corresponding strains.