Method and apparatus for testing materials

Description of the offer:

The knowledge that this offer is based on describes a device to perform stress tests on a given part, while subjecting that part to a harsh environment that simulates as closely as possible real world exposure. This technology was developed for testing rocket fuel containers, as they are exposed to very toxic and dangerous chemicals, and therefore impossible to safely and accurately test otherwise.

Environmental testing of materials involves exposing a test piece of a material to a specific environment (chemical, thermal, etc.) in order to reveal any adverse effects on its properties. One of the properties of the material that needs to be analyzed is its ability to withstand propagation of an existing defect, e.g. a surface crack. To do so, it is necessary to be able to subject the test piece to mechanical stresses and to observe defect propagation, which requires the test piece to be accessible during testing.

Prior art testing methods fall short when the previous requirements have to be combined with the necessity to expose the piece to a test environment that is corrosive, toxic, flammable, and/or likely to be contaminated in order to better mimic real world conditions. In aforementioned tests it was only possible to have the test sample in a leaktight receptacle, guaranteeing the environment fidelity and safety, but making the sample inaccessible for interaction and testing during the exposure, or to carry out tests on a test piece in which a portion of its surface is exposed to a flow of testing liquid or gas. In that way the test piece can be accessible in part during the test, but the characteristics of environment are difficult to control and cannot reproduce the real conditions encountered on a mechanical part while it is in use.

This innovation provides a method of testing that does not present these drawbacks, comprising of a receptacle provided with an opening with means for leak tight contact between the edges of said opening and a portion of a surface of a test piece of a material disposed outside the vessel. The described device  is equipped with a drainage system and can include means for optical inspection of the test piece and also for the application of mechanical stress to the sample (traction stress in parallel direction). The described setup allows the exposure of the sample to a sealed and therefore pristine environment, while performing the necessary stress tests. After the procedure, the potentially harsh chemicals can simply be drained and the sample is free for any further testing required.

Innovations and advantages:

When compared to prior art, the described product and method are quite innovative as they allow the testing of a given sample in previously impossible conditions, such as keeping said sample accessible for stress testing while avoiding the test environment contamination or exposure to the noxious chemicals.

The apparatus is robust enough to allow the testing of liquid, gaseous or solid environments, being also equipped with a special groove that retains an unsoiled portion of the testing agent for analysis purposes. As for the opening of the chamber contacting with the surface of the test piece, it is engineered to be leak tight, providing an adequate seal.

Domains of Application:

Even if it was developed within the space field material testing applications, this method and apparatus may be applied more generally to materials and chemistry corrosion testing of materials. It could be used in material testing laboratories, e.g. aerospace in general, chemical and oil industry.

It is particularly suited when the environment being tested requires extra caution from the user, either because they are highly susceptible to contamination, or because they are toxic or otherwise dangerous.