Biaxial Tensile Test Device Without Outgoing Bar
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Solution Overview
Problem
Existing bulge test devices for material deformation analysis are limited by the presence of an outgoing bar, which restricts access to the external surface of the sample, preventing precise temperature measurements and imaging analysis, and are constrained to a narrow range of deformations due to the need for long entry bars and quasi-static strain rates, making it difficult to study high-strain-rate material behavior relevant to automotive and aeronautical applications.
Innovation Solution
A mechanical device with a cell of increased mass (15-25 kg) integrated with support elements and shock absorbers, eliminating the outgoing bar and allowing the sample to absorb kinetic energy, enabling deformation measurement by imaging and extending the test duration to include rupture analysis at higher strain rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an outgoing bar is used to transmit energy from the sample, then the energy absorption and measurement function is achieved, but the access to the external surface of the blank is restricted, preventing precise temperature measurements and imaging analysis
Solution Approach 1:
The patent removes the outgoing bar from the device configuration. The cell is designed to directly absorb the outgoing wave without requiring an outgoing bar for energy transmission, thereby eliminating the obstacle that blocked access to the blank's external surface for imaging and temperature measurements
Solution Approach 2:
The patent introduces a shock absorber as an intermediary element between the cell and the base. This shock absorber absorbs the energy from the incoming wave and protects the base, replacing the need for an outgoing bar while maintaining energy absorption functionality
2Measurement precision
If a long entry bar is used to avoid wave superposition, then measurement accuracy is improved, but the test duration is reduced and access to large deformations and rupture is lost
Solution Approach 1:
The patent replaces the mechanical entry bar system with a hydraulic or pneumatic pressurization system. The chamber filled with liquid allows for controlled pressurization without the constraints of bar length, enabling both accurate measurement and extended test duration to capture large deformations and rupture
Solution Approach 2:
The patent uses a chamber filled with liquid (hydraulic system) to transmit pressure to the blank. This allows for controlled pressure application and extended test duration without the limitations of mechanical bar systems, enabling study of large deformations and rupture while maintaining measurement accuracy
3Adaptability or versatility
If the strain rate is increased to study high-strain-rate material behavior, then the relevance to automotive and aeronautical applications is improved, but the control of the cell position becomes difficult
Solution Approach 1:
The patent designs a single device that can perform both quasi-static tests (by controlling pressurization rate) and dynamic high-strain-rate tests (by rapid pressurization). The hydraulic/pneumatic system provides universal functionality across different strain rates while maintaining cell position control through fluid pressure management
Solution Approach 2:
The patent controls the strain rate by changing the pressurization rate of the liquid in the chamber. By adjusting the rate at which pressure is applied, the system can achieve both quasi-static and high-strain-rate conditions while maintaining cell position control through controlled fluid pressure application
4Adaptability or versatility
If a single device is used for both quasi-static and dynamic tests, then device versatility is improved, but the device complexity increases
Solution Approach 1:
The patent designs a universal testing device where the same hydraulic/pneumatic chamber system can perform both quasi-static tests (slow pressurization) and dynamic tests (rapid pressurization). The control system adjusts the pressurization rate to achieve different test conditions, eliminating the need for separate devices while maintaining structural simplicity
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 allows for precise imaging and measurement of sample deformation over a wider range of strain rates, including rupture, without the limitations of traditional devices, and enables the use of a single device for both quasi-static and dynamic tests, facilitating more comprehensive material behavior analysis.
Implementation Method 1
shock absorbers, which make it possible to absorb part of the kinetic energy received via the piston and/or entry bar
Implementation Method 2
the cell of the device has a mass greater than a predetermined threshold value, this mass being of the order of 15 to 25 kg and is integral with one or more support elements each adapted to put pressure on a shock absorber configured to absorb part of the energy received via the piston and/or the entry bar
Data Source
Figure 1~2
AI summary
Mechanical or electromechanical device (DBT) configured to carry out a deformation test on a material, comprising an input piston and/or bar (1), a cell (CEL), which comprises a chamber (2) and a holding die element (4) for holding a blank (3) that is to be deformed. The cell (CEL) of the device (DBT) is characterized by a deliberately large mass and is secured to at least one bearing element (5) designed to press on at least one damper (6) configured to absorb some of the energy received via the input piston and/or bar (1), the device (DBT) comprising no mechanical element of the "extending bar" type.