Ultrasonic Fatigue Testing Apparatus for High-Pressure Gas Environments
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Solution Overview
Problem
Existing high cycle fatigue testing devices are not suitable for conducting tests in high-pressure, hazardous atmospheres like hydrogen, as they require mechanical feedthroughs that can lead to leakage and safety issues.
Innovation Solution
The apparatus uses a pressure vessel with two chambers of different gas pressures to apply static stress to a specimen without mechanical feedthroughs, utilizing ultrasonic excitation and gas flow control to maintain a controlled strain ratio and pressure difference, thereby eliminating the need for mechanical rods or bellows.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If mechanical rods or bellows are used to apply static stress to the specimen, then the static stress application is achieved, but leakage risks increase and safety deteriorates in hazardous atmospheres
Solution Approach 1:
The patent replaces mechanical rods and bellows with a gas pressure system. Two gas chambers (first and second chambers) are used to apply static stress to the specimen through gas pressure differential, eliminating the need for mechanical feedthroughs that penetrate the pressure vessel wall and cause leakage risks.
Solution Approach 2:
The invention uses gas pressure to apply static stress to the specimen. The first gas chamber applies pressure through the first horn to one end of the specimen, while the second gas chamber applies pressure through the second horn to the other end, creating a controlled static stress state without mechanical penetrations.
2Force
If feedthroughs or bellows are used for mechanical rod transmission under controlled atmospheres, then static load transmission is achieved, but device complexity and difficulty of operation increase
Solution Approach 1:
The patent eliminates mechanical feedthroughs and bellows by using a fully pneumatic system. Gas chambers sealed within the pressure vessel apply forces through gas pressure, requiring no mechanical connections that penetrate the vessel wall, thereby simplifying the device structure and operation.
3Device complexity
If a single pressure vessel chamber is used, then the structure is simpler, but the ability to apply controlled static stress and maintain different gas pressures is reduced
Solution Approach 1:
The pressure vessel is segmented into two separate gas chambers (first and second chambers) that can be independently pressurized. This segmentation allows different gas pressures to be applied on either side of the specimen, enabling precise control of static stress while maintaining a relatively simple overall structure.
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
This solution allows for safe and effective high cycle fatigue testing in hazardous environments by reducing leakage risks and enabling testing under high pressures, while maintaining controlled strain ratios and optimizing stress application on the specimen.
Implementation Method 1
two ultrasonic transducers operating at frequencies lying between 10 and 100 kHz
Implementation Method 2
a converter (24) comprising an ultrasonic transducer for generating an ultrasonic excitation of the load train
Implementation Method 3
a first gas chamber (26) in which a load train comprising an upper, first horn (16) and a lower, second horn (18) is arranged... a first gas chamber (26) chargeable with a first gas pressure and a second gas chamber (28) chargeable with a second gas pressure different from said first gas pressure
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
An apparatus (10) for carrying out high cycle fatigue tests of a specimen (12) under high pressure comprises: a pressure vessel (14); a load train composed of a first horn (16) and a second horn (18) between which a specimen (12) is to be arranged, wherein said load train is arranged within an internal chamber of the pressure vessel (14); and a converter (24) adapted to apply ultrasonic waves into the load train by exciting the first horn (16) in order to apply a dynamic stress to the specimen (12). A base part (30) of the second horn (18) is movably seated in the pressure vessel (14) such that two separated chambers (26, 28) are formed within the pressure vessel (14) with the first chamber (26) for the specimen, wherein both chambers (26, 28) can be fed with gas and charged with different gas pressures in order to apply a static stress to the specimen.