Method and apparatus for examining the mechanical-dynamical properties of a workpiece
First Claim
1. A method for investigating the mechanical dynamic properties of a work piece, the method comprising:
- subjecting the work piece to at least one of cyclical tensile and cyclical compression stress along a first direction,producing a power signal representing the at least one of the tensile and compression stress of the work piece using a power-registering device,producing a distance signal representing a length change of at least one specified section of the work piece using a distance-registering device, andfeeding the power signal and the distance signal to an evaluation device that determines, from the power signal and distance signal obtained during at least one stress cycle, at least one of the characteristic values (Λ
;
tan α
1 ;
tan α
2 ;
ε
mean ;
ε
p) with respect to the work pieces damping properties or at least one of tensile and compression stiffness properties, nonelastic deformation properties, and plastic extension properties for the mechanical-dynamic properties of the specified section of the work piece,wherein the work piece is provided with a raster made of contrasting coding strips along a second direction and is swept by a laser beam with a prespecified scanning frequency running along a second direction within the framework of registering the distance,whereby the scanning frequency of the laser beam is larger than the frequency with which the work piece undergoes the at least one of cyclical tensile and cyclical compression stress, the intensity of the laser light modulated by the coding strips of the raster is registered and its time path forms the distance signal, andwhereby the evaluation device registers the length changes of different sections of the work piece, swept over by the laser light and defined in each case by two or more neighboring coding strips, from the time path of the distance signal and determines the characteristic value(s) for the mechanical-dynamic properties (Λ
;
tan α
1 ;
tan α
2 ;
ε
mean ;
ε
p) of the different sections of the work piece.
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Abstract
Described is a procedure for investigating the mechanical-dynamic properties of a work piece, whereby the work piece is subjected to cyclical tensile and/or compression stress in a first direction. A power signal representing the tensile and/or compression stress of a work piece is produced with the use of a power-registering device and produces a length change representing at least one specified section of the work piece my means of a distance-registering device. The power signal and distance signal are fed to an evaluation device, which determines a characteristic value for the mechanical-dynamic properties of the specified section from the power signal and distance signal obtained during one stress cycle. The procedure is distinguished by the fact that the work piece provided with a raster made of contrasting coding strips along a second direction is continuously swept by a laser beam with a specified scanning frequency along the second direction, and the intensity of the laser light modulated by the coding strips is registered. The time path of the distance signal corresponds to the registered intensity of the modulated laser light, and the evaluation device determines, from the time path of the distance signal, the length changes of different sections of the work piece defined by two or more coding strips and swept by the laser light and the characteristic values of these different sections for the mechanical-dynamic properties.
22 Citations
17 Claims
-
1. A method for investigating the mechanical dynamic properties of a work piece, the method comprising:
-
subjecting the work piece to at least one of cyclical tensile and cyclical compression stress along a first direction, producing a power signal representing the at least one of the tensile and compression stress of the work piece using a power-registering device, producing a distance signal representing a length change of at least one specified section of the work piece using a distance-registering device, and feeding the power signal and the distance signal to an evaluation device that determines, from the power signal and distance signal obtained during at least one stress cycle, at least one of the characteristic values (Λ
;
tan α
1 ;
tan α
2 ;
ε
mean ;
ε
p) with respect to the work pieces damping properties or at least one of tensile and compression stiffness properties, nonelastic deformation properties, and plastic extension properties for the mechanical-dynamic properties of the specified section of the work piece,wherein the work piece is provided with a raster made of contrasting coding strips along a second direction and is swept by a laser beam with a prespecified scanning frequency running along a second direction within the framework of registering the distance, whereby the scanning frequency of the laser beam is larger than the frequency with which the work piece undergoes the at least one of cyclical tensile and cyclical compression stress, the intensity of the laser light modulated by the coding strips of the raster is registered and its time path forms the distance signal, and whereby the evaluation device registers the length changes of different sections of the work piece, swept over by the laser light and defined in each case by two or more neighboring coding strips, from the time path of the distance signal and determines the characteristic value(s) for the mechanical-dynamic properties (Λ
;
tan α
1 ;
tan α
2 ;
ε
mean ;
ε
p) of the different sections of the work piece. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
-
-
13. Device for investigating the mechanical-dynamic properties of a work piece, comprising
a pulsator which subjects the work piece to at least one of a cyclical tensile and a cyclical compression stress along a first direction, a power-registering device, which produces a power signal representing the at least one of the cyclical tensile or cyclical compression stress of the work piece, a distance-registering device which produces a distance signal representing a length change of at least one specified section of the work piece, and an evaluation device to which is fed the power signal and distance signal and which determines at least one of the characteristic values (Λ - ;
tan α
1 ;
tan α
2 ;
ε
mean ;
ε
p) for the mechanical-dynamic properties of the specified section of the work piece with respect to at least one of its damping properties, tensile properties, compression properties, nonelastic deformation properties, and plastic extension properties from the power signal and distance signal obtained during one or several stress cycles, whereinthe distance-registering device contains a laser having a laser beam that constantly sweeps the work piece, which is provided with a raster along a second direction that is made of contrasting coding strips, with a prespecified scanning frequency running along the second direction, whereby the scanning frequency of the laser beam is larger than the frequency with which the work piece is subjected to the at least one of cyclical tensile or cyclical compression stress, the distance-registering device also includes a photodetector device which registers the intensity of the laser light modulated by the coding strips of the raster and gives its time path as a distance signal; and the evaluation device registers from the time path of the distance signal the length changes of different sections of the workpiece section swept by the laser light and defined by two or more neighboring coding strips and determines the characteristic values for the mechanical-dynamic properties (Λ
;
tan α
1 ;
tan α
2 ;
ε
mean ;
ε
p) for the different sections of the work piece. - View Dependent Claims (14, 15, 16, 17)
- ;
Specification