Resonance test system
First Claim
1. An apparatus for applying at least one cyclical load to a specimen, the specimen extending at least along a longitudinal axis, comprising:
- a mass;
an actuator mounted to the specimen and operatively associated with said mass, said actuator moving said mass along a linear displacement path that is perpendicular to the longitudinal axis of the specimen, wherein the specimen comprises a wind turbine blade that is rigidly mounted at a root end and unsupported at a tip end and wherein the actuator is mounted at a location between the root end and the tip end of the specimen such that the moving of the mass relative to the wind turbine blade applies a bending load to the specimen; and
a control system operatively associated with said actuator, said control system operating said actuator to reciprocate said mass along the linear displacement path at a reciprocating frequency, said reciprocating frequency being about equal to a resonance frequency of the specimen in a test configuration causing displacement of the tip relative to the longitudinal axis of the specimen.
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Accused Products
Abstract
An apparatus (10) for applying at least one load to a specimen (12) according to one embodiment of the invention may comprise a mass (18). An actuator (20) mounted to the specimen (12) and operatively associated with the mass (18) moves the mass (18) along a linear displacement path (22) that is perpendicular to a longitudinal axis of the specimen (12). A control system (26) operatively associated with the actuator (20) operates the actuator (20) to reciprocate the mass (18) along the linear displacement path (22) at a reciprocating frequency, the reciprocating frequency being about equal to a resonance frequency of the specimen (12) in a test configuration.
47 Citations
20 Claims
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1. An apparatus for applying at least one cyclical load to a specimen, the specimen extending at least along a longitudinal axis, comprising:
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a mass; an actuator mounted to the specimen and operatively associated with said mass, said actuator moving said mass along a linear displacement path that is perpendicular to the longitudinal axis of the specimen, wherein the specimen comprises a wind turbine blade that is rigidly mounted at a root end and unsupported at a tip end and wherein the actuator is mounted at a location between the root end and the tip end of the specimen such that the moving of the mass relative to the wind turbine blade applies a bending load to the specimen; and a control system operatively associated with said actuator, said control system operating said actuator to reciprocate said mass along the linear displacement path at a reciprocating frequency, said reciprocating frequency being about equal to a resonance frequency of the specimen in a test configuration causing displacement of the tip relative to the longitudinal axis of the specimen. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A system for vibrating a specimen, the specimen extending at least along a longitudinal axis from a first to a second end, comprising:
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reciprocating mass means operatively associated with the specimen for sinusoidally vibrating the specimen along the longitudinal axis at about a resonance frequency of the specimen in a test configuration, wherein the specimen is rigidly supported at the first end and unsupported at the second end and wherein the reciprocating mass means is mounted to the specimen at a location between the first and second ends; and displacement control means operatively associated with said reciprocating mass means for varying a vibrational displacement of the specimen, wherein said reciprocating mass means comprises;
a mass; and
actuator means operatively associated with said mass for reciprocating said mass along a displacement path that is perpendicular to the longitudinal axis of the specimen such that the mass does not contact the specimen during the reciprocating.
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11. A method for vibrating a wind turbine blade specimen, the specimen extending at least along a longitudinal axis from a root to a tip, comprising:
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mounting a mass to the specimen nearer to the tip than to the root so that said mass can be reciprocated along a linear displacement path that is perpendicular to the longitudinal axis of the specimen to apply a flap load to the specimen; and reciprocating the mass along the linear displacement path at a reciprocation frequency that is about equal to a resonance frequency of the specimen in a test configuration, wherein the mass remains spaced apart from the specimen during reciprocating along the linear displacement path. - View Dependent Claims (12, 13, 14, 15)
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16. An apparatus for applying at least one cyclical load to a specimen, the specimen extending at least along a longitudinal axis, comprising:
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a mass; an actuator mounted to the specimen and operatively associated with said mass, said actuator moving said mass along a linear displacement path that is substantially perpendicular to the longitudinal axis of the specimen; a transverse load actuator operatively associated with the specimen, said transverse load actuator applying to the specimen a cyclical load in a transverse direction, said transverse direction being substantially perpendicular to the longitudinal axis of the specimen and to the linear displacement path; and a control system operatively associated with said actuator and said transverse load actuator, said control system operating said actuator to reciprocate said mass along the linear displacement path at a reciprocating frequency, said reciprocating frequency being about equal to a resonance frequency of the specimen in a test configuration, said control system operating said transverse load actuator to vary the cyclical load at about the reciprocating frequency. - View Dependent Claims (17, 18, 19, 20)
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Specification