Measuring and testing – With fluid pressure – Dimension – shape – or size
Patent
1989-01-24
1990-03-27
Williams, Hezron E.
Measuring and testing
With fluid pressure
Dimension, shape, or size
73807, G01M 302
Patent
active
049109979
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
This invention relates to testing apparatus and a method of testing using such apparatus. In particular, it relates to apparatus usable in the testing of buildings under wind stress.
In the testing of buildings, a uniformly distributed load can be applied on to a horizontal test surface by weights or sand, provided there is no need to change the load quickly. However if an upward load is required, the test surface is not horizontal, or the load is to be varied quickly (to stimulate wind effects, for example), it becomes impractical to generate proof loads in this way. Apparatus has therefore been devised in which a pair of co-operating valves may be coupled to an air circulating system to produce a rapidly fluctuating stress system.
SUMMARY OF THE INVENTION
According to one aspect of the present invention an apparatus for applying a fluctuating stress includes means for defining a pressure enclosure and air compression means having an intake and an outlet characterised by a control valve assembly connecting the pressure enclosure to the air compression means, the control valve assembly being provided with movable valve members continuously adjustable between first positions where the intake is connected to the pressure enclosure and the outlet is connected to atmosphere and second positions where the intake is connected to atmosphere and the outlet is connected to the pressure enclosure through intermediate positions where both intake and outlet are connected partly to atmosphere and partly to the pressure enclosure.
An embodiment of the invention consists of apparatus for applying a fluctuating stress including means for defining a pressure enclosure and air compression means characterised by the means to compress air having an inlet port and an outlet port, first conduit means to conduct air from the outlet port, second conduit means to conduct air to the inlet port, first valve means having an inlet port connected to the first conduit means and having a pair of outlet ports together with adjustable valve members to divert air from a first to a second of its outlet ports, second valve means connected to the second conduit means and having a pair of inlet ports together with adjustable valve members to control relative opening of its first and second inlet ports and an outlet port connected to the second conduit means, coupling means to couple the adjustable valve members of the valve means, third conduit means connected to one outlet port of the first valve means and one inlet port of the second valve means, the third conduit means having a port which is connectable to means defining a pressure enclosure whereby air pressure therein may be varied.
According to another aspect of the invention a method of testing a structure by applying fluctuating stress thereto includes steps of defining a pressure enclosure abutting the structure, connecting to the pressure enclosure air compression means having an intake and an outlet and characterised by the fluctuating stress being applied by varying the pressure in the pressure enclosure by operating a control valve assembly connecting the pressure enclosure to the air compression means, operation of the control valve assembly varying the positions of the movable valve members continuously between first positions connecting the intake to the pressure enclosure and the outlet to atmosphere and second positions connecting the intake to atmosphere and the outlet to the pressure enclosure through intermediate positions connecting both intake and outlet partly to atmosphere and partly to the pressure enclosure.
The movable valve members are preferably adjustable under computer controlled means whereby pressure within the pressure enclosure is varied according to a program which may be predetermined or random.
BRIEF DESCRIPTION OF THE DRAWINGS
An embodiment of the invention will now be described by way of example with reference to the accompanying drawings in which:
FIG. 1 shows the general assembly of a test rig;
FIG. 2 shows a method o
REFERENCES:
patent: 2345387 (1944-03-01), Elsey
patent: 2694924 (1954-11-01), Matlock et al.
patent: 2826910 (1958-03-01), Bell et al.
patent: 3332281 (1965-07-01), Spangler
patent: 4517826 (1985-05-01), Cole et al.
patent: 4635469 (1987-01-01), Modera et al.
Research Disclosure, No. 244, Aug. 1984, (Havant, Hampshire, GB) Automatic Wind-Uplift, p. 387, by K. R. Johnson.
The Secretary of State of the Environment
Williams Hezron E.
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