Material Testing Force Limits Based on Crosshead Position
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional material testing machines are limited by physical constraints that restrict load string height, leading to reduced testing force capabilities when extended heights are required, which can cause components like ball screws to buckle under high compressive forces.
Innovation Solution
The system employs a control circuitry to adjust testing force limits based on the position or distance of the crosshead relative to the base, allowing extended height testing with higher force limits within normal specimen lengths and reducing force limits when the crosshead is outside a predetermined range to prevent component buckling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the load string height is extended to accommodate longer specimen lengths, then the testing versatility and range are improved, but the maximum testing force capability deteriorates due to component buckling under high compressive forces
Solution Approach 1:
The patent implements dynamic adjustment of the upper testing force limit based on the crosshead position. The control circuitry continuously monitors the distance between the crosshead and base, and automatically adjusts the force limit accordingly. When the crosshead is within normal operating range, the full rated capacity is permitted; when extended beyond the threshold distance, the system reduces the upper force limit to prevent ball screw buckling, thus enabling extended height testing while maintaining safety
Solution Approach 2:
The system changes the operational parameters (testing force limit) based on the system state (crosshead position). By establishing a relationship between position and force capacity, the patent allows the machine to operate at different force levels depending on the load string height, effectively expanding the testing range without permanently compromising the force capability
2Productivity
If the upper testing force limit is maintained at rated capacity throughout the entire range, then the testing efficiency and productivity are improved, but the reliability deteriorates due to risk of component damage from buckling
Solution Approach 1:
The control circuitry implements a feedback mechanism that continuously monitors the crosshead position and adjusts the upper testing force limit accordingly. The system receives position data, compares it against predetermined thresholds, and automatically modifies the force limit parameter to prevent buckling when extended heights are used, thus maintaining both efficiency and reliability
Solution Approach 2:
The system takes preliminary protective action by preemptively reducing the force limit before buckling can occur. By monitoring position and adjusting limits in advance, the patent prevents harmful effects rather than reacting after damage occurs, ensuring component safety while maintaining testing capability within safe parameters
Data Source
AI summary
Disclosed example material testing systems include: a test frame; a base configured to grip a first position on a test specimen; a crosshead configured to be coupled to a second position on the test specimen, and to be actuated to transfer testing force to the test specimen during a material test; an actuator configured to actuate the crosshead along the test frame and to apply the testing force to the crosshead; and control circuitry configured to: control the actuator to apply the testing force to a specimen via the crosshead, such that the testing force does not exceed an upper limit; and while a distance between the crosshead and the base is at least a threshold distance, reduce the upper limit on the testing force from a value of the upper limit while the distance between the crosshead and the base is less than the threshold distance.