A system for and a method of measuring ultrasonic wave velocities in a subterranean core specimen is provided. Ultrasonic wave velocities are measured from the side surfaces (faces) of a polygonal-shaped core specimen having at least ten sides or faces. Stress is introduced to the core specimen by hydraulic rams associated with each set of opposing sides. As stress is applied, ultrasonic waves are introduced to at least one side of the set of opposing sides and the wave transmitted through the core specimen is measured. Subsequently, the wave velocity for the ultrasonic wave can be calculated based on the measurements taken. Also, elastic properties associated with the core specimen can be calculated.

A sensor device, comprising two symmetrically disposed sonolucent wedges (5), and a connecting piece for fixedly connecting the two sonolucent wedges (5); the upper surfaces of the sonolucent wedges (5) are provided with inclined planes; installation holes are formed on the inclined planes; transducers (3) are installed in respective installation holes; one transducer (3) is used to generate ultrasonic waves, and the other transducer (3) is used to receive the ultrasonic waves generated by the previous transducer (3). The residual stress detection system comprises a sensor device, an ultrasonic transmission card, and a data acquisition card.

A fastener and a system, apparatus, and method for monitoring a fastener are described. The fastener includes a head portion, a shank portion, a transponder, and a compression spring, wherein the head portion includes a mounting portion, and wherein the transponder is disposed in the mounting portion of the head portion. The transponder is arranged to monitor the shank portion, and includes an ultrasonic sensor and a signal processing circuit. The ultrasonic sensor is affixed to a transducer hosting surface, and is urged against the transducer hosting surface by placement of the printed circuit board in the head portion with the compression spring intervening therebetween. The ultrasonic sensor communicates with the signal processing circuit via the compression spring. The signal processing circuit captures a signal from the ultrasonic sensor and transforms the signal into a parameter corresponding to a tensile force being exerted by the fastener.

The disclosure provides a method, system, device and medium for online monitoring of a plane stress field without baseline data based on a piezoelectric transducer array. Since Lamb waves have complex multi-mode characteristics, a suitable excitation frequency needs to be selected according to geometric dimensions of the structure to be measured, and then, only low-order mode Lamb waves are excited inside the measured structure to avoid serious waveform aliasing. For isotropic measured objects, anisotropic characteristics will be generated under the action of pre-stresses, that is, the propagation velocities of ultrasonic waves in all directions are different, but there is a linear relationship between velocity changes in different propagation directions and stresses. Therefore, there is still a linear relationship between the difference of velocity changes in different propagation directions and the stress. According to this characteristic, a characterization method of an absolute stress field without baseline data can be implemented. The method of the disclosure can make full use of the low attenuation characteristics of the Lamb waves to realize online monitoring of the plane stress field with a large coverage area.

An acoustic disdrometer is provided for measuring precipitation. The acoustic disdrometer has an acoustic transducer positioned within an acoustic chamber defined by an acoustic shell. Precipitation impacting the acoustic shell generates sound waves that are collected by the acoustic transducer for processing.

A system, device, and methods include or utilize a microphone, a processor, and a user interface. The microphone senses sound and in response outputs a sound signal indicative of the sound. The processor is coupled to the microphone to receive the sound signal, configured to analyze the sound signal to identify in the sound signal an impact of a golf club with a golf ball during a swing of the golf club and determine a characteristic of the swing of the golf club based on a portion of the sound signal corresponding to sound sensed, at least in part, before the impact. The user interface is coupled to the processor and configured to display information related to the characteristic of the swing as determined by the processor.

Methods and apparatus, including computer program products, are provided for determining rail stress. The method may include generating at least one ultrasonic guided wave to enable the at least one ultrasonic guided wave to propagate through a rail; detecting at least one of a fundamental frequency component of the at least one ultrasonic guided wave, one or more harmonics of the at least one ultrasonic guided wave, and/or a mixing component of the at least one ultrasonic guided wave; and determining a stress of the rail based on at least a nonlinearity parameter determined from the detected at least one of the fundamental frequency component, the one or more harmonics, and the mixing component. Related apparatus, systems, methods, and articles are also described.

A surface acoustic wave sensor system for determining environmental conditions on a substrate. The system comprises an interrogator for producing an RF interrogating signal transmitted by an antenna to an interdigital transducer mounted on the substrate for producing an incident surface acoustic wave responsive to the interrogating signal. A plurality of reflector arrays mounted on the substrate produce a like plurality of reflected surface acoustic waves; a spacing between adjacent ones of the plurality of reflector arrays comprising a non-uniform distance. The plurality of reflected surface acoustic waves are responsive to the environmental condition and exhibit a characteristic from which the environmental condition can be determined by a processing component.

A remote tension measurement system and method of use is provided for detection and estimation of tension in two-dimensional and three-dimensional inflatable structures. Given a spacing distance and a known mass of the membrane-formed structure, measurement points are determined to define a measurement region of the structure. A non-invasive sensor monitors the measurement points to detect a transverse wave moving along the measurement region at an angle to a straight path between measurement points. Propagation speed for the transverse wave is calculated and tension for the measurement region is deduced from the calculation. The solution exploits either proactively introduced, pre-existing, induced by normal environmental conditions) and/or multiple transverse vibrations in the membrane-formed structure. Propagation speed is calculated deterministically based on an analysis of the arrays of measurement points.

An environmental condition may be measured with a sensor (10) including a wire (20) having an ultrasonic signal transmission characteristic that varies in response to the environmental condition by sensing ultrasonic energy propagated through the wire using multiple types of propagation, and separating an effect of temperature on the wire from an effect of strain on the wire using the sensed ultrasonic energy propagated through the wire using the multiple types of propagation. A positive feedback loop may be used to excite the wire such that strain in the wire is based upon a sensed resonant frequency, while a square wave with a controlled duty cycle may be used to excite the wire at multiple excitation frequencies. A phase matched cone (200, 210) may be used to couple ultrasonic energy between a waveguide wire (202, 212) and a transducer (204, 214).