In Situ Chamber Assembly for Isochoric Material Load Testing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional material testing chambers fail to perform mechanical testing isochorically due to changes in fluid volume and pressure during specimen loading, masking the load signal from specimen deflection and complicating data interpretation.
Innovation Solution
An in situ chamber assembly with a pull rod that maintains a constant fluid volume and pressure within the pressure vessel, ensuring load measurements are independent of chamber pressure, achieved through a sliding and sealing relationship between the pull rod and end caps, allowing isochoric, isobaric, and isothermal testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional material testing chambers are used, then mechanical testing can be performed, but load measurements are masked by pressure changes due to fluid volume expansion/contraction
Solution Approach 1:
The testing chamber is segmented into a rigid pressure vessel and a movable pull rod assembly. The pull rod is divided into a fixed portion and a movable portion that can slide independently within the pressure vessel, allowing separate control of mechanical loading and pressure maintenance.
Solution Approach 2:
A fluid coupling system acts as an intermediary between the movable pull rod and the specimen. The fluid transmits force from the pull rod to the specimen while maintaining constant pressure, isolating the load measurement from pressure variations.
2Measurement precision
If fluid volume changes during testing, then pressure adjustments can be made, but load signal from specimen deflection becomes masked
Solution Approach 1:
The system changes the parameter of fluid volume by using a movable pull rod that can slide within the pressure vessel. This allows the fluid volume to remain constant while still enabling mechanical testing through the coupling mechanism.
Solution Approach 2:
The harmful effect of fluid volume changes is extracted and isolated into a separate movable pull rod assembly. The pull rod's movement is decoupled from the pressure vessel volume, allowing independent control of mechanical loading without affecting pressure stability.
3Adaptability or versatility
If pressure changes occur during testing, then in situ conditions can be simulated, but data interpretation becomes complicated
Solution Approach 1:
The system incorporates pressure sensing and feedback control to maintain constant pressure throughout the testing process. The pressure control system continuously monitors and adjusts fluid volume to compensate for any pressure changes, ensuring stable in situ conditions.
Solution Approach 2:
The fluid coupling system is pre-configured to maintain constant pressure before testing begins. The movable pull rod assembly is designed to compensate for pressure changes proactively, preventing them from affecting the load measurements during the test.
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
Enables accurate measurement of material properties by isolating the load signal from pressure changes, facilitating precise mechanical testing under extreme conditions, simulating environments like oil and gas exploration and aerospace applications.
Implementation Method 1
A pull rod extends through the pressure vessel and has a sliding and sealing relationship with the first and second end caps
Implementation Method 2
A fluid may be sealed within the pressure vessel with the at least one specimen exposed to the fluid
Data Source
AI summary
An in situ chamber assembly for mechanical testing of materials. The in situ chamber assembly includes a pressure vessel having first and second end caps. A pull rod extends through the pressure vessel and has a sliding and sealing relationship with the first and second end caps. A specimen retainer assembly is disposed within the pressure vessel. The specimen retainer assembly including a fixed portion coupled to the pressure vessel and a movable portion coupled to the pull rod. At least one specimen is positioned between the fixed portion and the movable portion of the specimen retainer assembly such that movement of the pull rod relative to the pressure vessel applies a load on the at least one specimen. In operation, movement of the pull rod relative to the pressure vessel occurs isochorically and isobarically.