Abstract:
A thin film stress sensor measures the maximum compressive stress between two elements that are compressed together. The sensor is formed from a thin RTV film impregnated with microballoons and reinforced with carbon fibers to restrain the lateral deformation of the RTV so that more uniform pressure can be exerted on the microballoons when the sensors are uniaxially compressed.
Abstract:
A load indicating device and a method of using a load indicating device for monitoring the deformation in and imparting torque to a load bearing member are disclosed and claimed. An ultrasonic transducer, grown on one surface of a load bearing member, such as a fastener, is used to determine the length, stress or other tensile load dependent characteristic of the member using ultrasonic techniques.
Abstract:
A sensor comprising a deformable medium, such as rubber, an ultrasonic transducer for transmitting a signal through the medium to a face of the medium and for sensing an echo of the signal returned from the face through the material to the transducer and circuit means for determining the time differential between transmission of the signal and return of the echo and for converting the time signal into a distance measurement.
Abstract:
An apparatus for ultrasonically measuring concentrations of stress in objects of interest. The apparatus includes an ultrasonic transducer array for propagating acoustic waves in an object of interest along a plurality of determinable directions and from a plurality of determinable positions. A time interval counter measures the time of flight of the acoustic waves along the determinable directions and from the determinable positions. The time of flight measurements are reconstructed into a map of the variations in acoustic velocity within the object. The changes in acoustic velocity are then mathematically converted into a map of stress concentration areas in the object of interest.
Abstract:
체결 작업 중에 볼트와 접합 나사산 부분 간의 나사산 조인트에서 클램프력(F)을 평가하기 위한 장치 및 방법이 제공된다. 조인트에 제공된 토크(T)는 연속적으로 측정되고 볼트 내에서 펄스의 TOF가 측정될 수 있도록 볼트 내로 초음파 펄스가 유도된다. 측정된 토크(T)의 증가에 응답하여, 토크의 증가 속도(dT/dα)가 결정되고, 이로부터 토크(T)가 볼트 변형으로 인해 증가하기 시작하는 초기 회전각(α0)이 측정될 수 있다. 추가로, TOF의 증가 속도(dTOF/dα)가 측정된다. 체결 작업 동안에 ΔTOF의 총 증가는 그 뒤에 TOF의 증가 속도(dTOF/dα)와 초기 회전각(α0)을 기초로 측정될 수 있다.