Measuring and testing – Vibration – Vibrator
Reexamination Certificate
1999-07-26
2001-04-10
Moller, Richard A. (Department: 2856)
Measuring and testing
Vibration
Vibrator
C073S012010, C073S012090
Reexamination Certificate
active
06212954
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to improvements in or relating to test apparatus and is more particularly concerned with apparatus which allows different crash scenarios to be simulated in an attempt to optimise factors for better safety performance of the structure under test.
Generally, in order to test the safety of large-scale structures such as motor vehicles, road safety barriers, large aeroplanes, space capsules or shuttles, high speed train bodies or crash combinations (for example two vehicles or a vehicle and barriers) the normal procedure would be to guide the structure under test in front of a specially constructed wall or barrier or other vehicle. Measurements would then be taken from transducers or gauges positioned on the structure under test. Certainly, in the case of aeroplanes such tests can be very complex and expensive and tend to be subject to high risks of failure.
An object of the present invention is to alleviate the aforementioned, or other, problems associated with crash tests more particularly for large structures.
SUMMARY OF THE INVENTION
According to one aspect of the present invention there is provided compression wave or pulse generation apparatus capable of generating a compression wave or pulse in a vehicle or large structure under test, said compression wave generation apparatus comprising an impactor bar or member held, in use, adjacent one end of the vehicle or large structure under test and supported to resist movement in a direction away from said vehicle or large structure when the impactor bar/member is preloaded in said direction by actuator means, the arrangement being such that, in use, the preload force can be quelled suddenly for example by triggering an explosive bolt in the impactor bar/member, so that the impactor bar/member is released into impact or energy transfer with the vehicle or large structure thereby transmitting a compression wave or pulse through the vehicle or large structure.
Usually, the apparatus will include energy flow transducers arranged to measure the mechanical energy propagated along the structure or vehicle submitted to the stress wave under simulated crash conditions.
Preferably, the transducers are in the form of bars or elongate members arranged, in use, to measure stress values at selected (critical) points of the structure. Preferably, each bar has the same mechanical impedance as the part of the structure being measured by that bar and/or the length of the transducer bar is such as to prevent wave reflection (at the end of the bar remote from the point of the structure to which the transducer bar is connected) before the end of the measuring time period.
Usually, the apparatus will include transducer bars arranged longitudinally of the vehicle or structure under test in addition to transducer bars arranged at an angle or transversely of said vehicle or structure under test.
The actuator means is preferably a hydraulic or pneumatic actuator.
Usually, said apparatus will be arranged to generate a well known compression pulse.
In one embodiment of the apparatus the impactor bar/member is generally cylindrical and provided with an explosive bolt positioned diametrically of a lesser diameter portion (usually closer to the actuator means than to the structure under test). The impactor bar/member may be shaped to match the contour of the structure under test and said bar/member is held adjacent the structure by means of a blocking system or fixed support, a wider diameter portion of the bar/member engaging the blocking system or fixed support when the impactor bar/member is subject to pre-load conditions in a direction away from the structure under test.
According to a further aspect of the present invention there is provided compression wave or pulse generation apparatus capable of generating a compression wave or pulse in a vehicle or large structure under test, in combination with said vehicle or large structure equipped with transducer bars or members (preferably arranged both longitudinally and transversely of the vehicle/large structure) said transducer bars or members being positioned to collect wave propagation data from selected or critical points of the structure.
Further advantageous features of the compression wave or pulse generation apparatus will be evident from the following description and drawings.
Two embodiments of compression wave or pulse generation apparatus in accordance with the present invention will now be described, by way of example only, with reference to the accompanying, much simplified diagrammatic drawings in which:
REFERENCES:
patent: 2474235 (1949-06-01), Dresser et al.
patent: 5003811 (1991-04-01), Shannon et al.
patent: 5184499 (1993-02-01), Oppliger et al.
Patent Abstracts of Japan vol. 007, No. 035 (P-175), Feb. 10, 1983 disclosing JP 57 187635 A (Mitsubishi Jukogyo KK), Nov. 18, 1982, (see abstract).
Albertini Carlo
Labibes Kamel
European Community
Moller Richard A.
Welsh & Katz Ltd.
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