US 5,134,891 AGranted

Device to determine the coefficient of the hydric expansion of the elements of a composite structure

AssigneeSociete Nationale Industrielle et Aerospatiale

InventorsMaurice Canevet, Pascal Lesage

Life of this patent

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Abstract

So as to determine the coefficient of hydric expansion .beta. of the elements of a composite structure, a sample of this structure is placed in a rigid cradle (10) so that one extremity of the sample is rigidly maintained and that the length variations of the sample are measured by a displacement transducer (12) borne by the cradle. The transducer (12) is preferably a linear differential transformer contact transducer and it is kept under constant humidity by injecting dry air through a flexible tube (60, 64) connected to its rear section. By placing the cradle (10) bearing the sample in a climatic chamber (40), whose humidity is made to vary at a constant temperature, and by at the same time measuring the weight of the sample, it is possible to determine the coefficient .beta..

Claims6

Dependent claims

System making it possible to determine the coefficient of the hydric expansion .beta. of the elements of a composite structure and including:

a rigid cradle made of a thermically stable material and including means to maintain in a desired position a sample of said structure and means to immobilize a first extremity of the sample;
a displacement transducer mounted on the rigid cradle opposite a second extremity of the sample opposing the first extremity so as to measure the length variations of the sample;
a tube for admitting dry air into the transducer and connected to a dry air source and having one extremity opposing said source overlapping one rear section of the displacement transducer;
a climatic chamber for receiving the rigid cradle and its displacement transducer and comprising means to vary the humidity of the atmosphere surrounding the cradle and the transducer within a determined range;
and
means to measure the weight variation of the sample.

3 more elements

Dependencies are inferred from the claim text.

Facts

Application: 07/603,458Filed 25 Oct 1990
Priority: FR 89 1421230 Oct 1989
Granted: 4 Aug 1992
Term ends: Not estimatedThe source records don’t support an estimate.

Classification4 codes

G01B 5/30
Measuring arrangements characterised by the use of mechanical techniques: for measuring the deformation in a solid, e.g. mechanical strain gauge
G01N 19/10
Investigating materials by mechanical methods: measuring moisture content, e.g. by measuring change in length of hygroscopic filament; Hygrometers
G01B
Measuring length, thickness or similar linear dimensions
G01N
Investigating or analysing materials by determining their chemical or physical properties