Rock Direct Tensile Testing With Integrated Elastic Wave Detection
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Solution Overview
Problem
Existing rock tensile test methods, both indirect and direct, face issues such as low accuracy, high apparatus cost, labor-intensive operations, safety hazards, and inability to perform acoustic detection during direct tensile tests, particularly when using conventional material compression machines.
Innovation Solution
An integrated acoustic detection and rock direct tensile test machine that can be used on conventional material test machines, ensuring failure occurs at the part with the lowest bearing force, featuring a compact design with acoustic components at clamp holders, allowing for acoustic detection during the test, and reducing the need for separate tensile apparatus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If indirect tensile method (Brazilian splitting) is used, then operation simplicity and universality are improved, but measurement accuracy deteriorates due to end loading zone influence and inability to ensure fracture surface follows predetermined loading surface
Solution Approach 1:
The patent inverts the conventional indirect tensile approach by using direct tensile loading through a specialized apparatus. Instead of applying compressive load to induce tensile failure (indirect method), the system directly applies tensile load to the rock sample using a dog-bone shaped specimen geometry, ensuring the fracture occurs at the intended location and accurately reflects true tensile strength
Solution Approach 2:
The patent segments the loading function by separating the tensile loading mechanism from the compression test machine. A specialized direct tensile apparatus with separate loading frames and hydraulic actuators is introduced, allowing independent control of tensile load application while the compression machine provides the base testing platform
2Measurement precision
If direct tensile method is used, then measurement accuracy is improved, but apparatus complexity and cost increase requiring separate tensile testing machine
Solution Approach 1:
The patent merges the direct tensile testing apparatus with the conventional compression testing machine into an integrated system. The tensile loading frames, hydraulic actuators, and control systems are combined with the compression machine's base structure, allowing both tensile and compression tests to be performed on a single unified platform
Solution Approach 2:
The patent creates a multi-functional testing apparatus that can perform both direct tensile tests and compression tests. The system uses interchangeable loading frames and adjustable hydraulic actuators to accommodate different test types, eliminating the need for separate dedicated tensile and compression testing machines
3Adaptability or versatility
If conventional compression machine is used for indirect tensile test, then equipment availability is improved, but acoustic detection capability deteriorates due to inability to monitor crack propagation
Solution Approach 1:
The patent introduces acoustic emission sensors as intermediary detection devices that monitor the rock sample during direct tensile testing. These sensors detect acoustic waves generated by crack propagation and micro-fractures, providing real-time information about the failure process while the compression machine provides the mechanical loading
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 provides accurate tensile test results with reduced costs and safety risks, enabling operation by a single person, and allows for acoustic detection, overcoming the limitations of traditional methods by ensuring the failure occurs at the weakest point and being compatible with triaxial test machines.
Implementation Method 1
an upper channel is provided inside the upper clamp holder, one end of the upper channel is communicated with the outside, the other end is provided with an acoustic transmitting probe, and a transmitting direction of the acoustic transmitting probe is downward; and a lower channel is provided inside the lower clamp holder, one end of the lower channel is communicated with the outside, the other end is provided with an acoustic receiving probe, and the acoustic receiving probe receives an acoustic wave transmitted by the corresponding transmitting probe
Data Source
AI summary
An integrated acoustic detection and rock direct tensile test machine includes a support frame. A top of the support frame is provided with a top plate and a bearing plate is provided above the top plate. The bearing plate is provided with force transferring rods, lower ends of which are provided with a tensile base. A top of the tensile base is provided with a lower clamp holder and a bottom of the top plate is provided with an upper clamp holder. An upper channel is provided inside the upper clamp holder. The upper channel is provided with an acoustic transmitting probe. A lower channel is provided inside the lower clamp holder. One end of the lower channel is communicated with the outside, the other end is provided with an acoustic receiving probe. The lower channel extends to a bottom of a clamping chamber of the lower clamp holder.