The present invention relates to a mechanical resonator device. The resonator device comprises a resonator element made of an elastic material under tensile stress and adapted for sustaining at least one oscillation mode; and a clamping structure supporting the resonator element. The clamping structure has a phononic density of states exhibiting a bandgap or quasi-bandgap such that elastic waves of at least one polarisation and/or frequency are not allowed to propagate through the clamping structure. The resonator element and the clamping structure are configured to match with a soft-clamping condition that elastic waves of polarisation and/or frequency corresponding to the at least one oscillation mode of the resonator penetrate evanescently into the clamping structure in a manner such as to minimize bending throughout the entire resonator device. Thereby, bending related loss may be minimized and the Q-factor of the mechanical resonator may be maximized.

A method of determining stress within a composite structure is provided which includes coupling a sensor to a composite structure under load having embedded therein a plurality of particles, wherein the particles at room temperature are paraelectric or ferroelectric, transmitting an electromagnetic radiation to the sensor, thereby generating an electromagnetic field into the composite structure, sweeping frequency from a first frequency to a second frequency in a pulsed manner, receiving reflected power from the composite structure, determining the resonance frequency of the sensor, and translating the resonance frequency of the sensor to stress within the composite structure.

A method of determining stress within a composite structure is provided which includes coupling a sensor to a composite structure under load having embedded therein a plurality of particles, wherein the particles at room temperature are paraelectric or ferroelectric, transmitting an electromagnetic radiation to the sensor, thereby generating an electromagnetic field into the composite structure, sweeping frequency from a first frequency to a second frequency in a pulsed manner, receiving reflected power from the composite structure, determining the resonance frequency of the sensor, and translating the resonance frequency of the sensor to stress within the composite structure.

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).

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).

A method, apparatus and system are disclosed for the measuring directly in units of force or mass huge load of form 10 to 1000 tons or more. The system includes a unique load carrying member to which the huge load is applied and based on readings of three types of ultrasonic waves and the change in the dimensions of the load carrying member it is able to directly calculate the force in units of newtons or units of mass in kilograms of the applied load.

A method, apparatus and system are disclosed for the measuring directly in units of force or mass huge load of form 10 to 1000 tons or more. The system includes a unique load carrying member to which the huge load is applied and based on readings of three types of ultrasonic waves and the change in the dimensions of the load carrying member it is able to directly calculate the force in units of newtons or units of mass in kilograms of the applied load.

An amplitude detecting method and a material tester are provided. As functional blocks of a program that is installed in a personal computer and is stored in a memory, a measurement noise eliminating part that eliminates measurement noise, a vibration noise eliminating part that eliminates vibration noise assumed to be caused by an inertial force according to a natural vibration according to reach of an impact of breakage or destruction of a test piece at the entire tester, an amplitude detecting part that detects the amplitude of a natural vibration superimposed in the data period used for evaluating material characteristics, and a display control part that controls display of an amplitude value of the natural vibration and a test result on the display device are included.

An apparatus for orienting an accelerometer on a post-tensioned rod is provided. The apparatus includes a first open channel having a first sidewall forming a substantially half cylinder shape along at least a portion of a length of the first open channel, and a first axis along a length of the first open channel. The apparatus further includes a second open channel having a second sidewall forming a substantially half cylinder shape along at least a portion of a height of the second open channel, and a second axis along a height of the second open channel. The apparatus further includes a stopper wall having an inner surface disposed internal to a top end of the second channel. The inner surface of the stopper wall is substantially perpendicular to the second axis. The first axis is substantially perpendicular to the second axis. The first and second channels are contiguous.

A force sensor includes a frame and an oscillation structure which has arms and can oscillate freely in the frame. The arms are fixed to suspension frame regions and run transverse to one another at least in sections. At least one conductor extends along at least two arms. An AC voltage can be applied to the at least one conductor to excite at least one oscillation mode of the oscillation structure with a resonant frequency using Lorentz force. The force sensor is designed such that the suspension regions are at least partially spatially displaced relative to one another when a force is applied to the frame, that the magnitude of the spatial displacement of the suspension regions depends on the magnitude of the force, and that the spatial displacement of the suspension regions causes detuning of the resonant frequency, the magnitude of which depends on the spatial displacement magnitude.