Provided is a measurement method including measuring, by using a piezoelectric sheet sensor in contact with a measurement object, vibration transmitted from the measurement object to the piezoelectric sheet sensor and measuring pressing force between the measurement object and the piezoelectric sheet sensor.

An electronic device including an actuator and a driving circuit electrically coupled to the actuator. The driving circuit can be configured to determine a resonance frequency of the actuator and deliver a driving frequency matching the resonance frequency to the actuator, as well as a driving voltage. The electronic device also includes a memory and a processor. The processor can determine the presence of a force applied to the electronic device based on the resonance frequency of the actuator. Based on determining a force is being applied to the electronic device, the processor can execute a predetermined function of the electronic device.

A method of determining bearing preload by vibration measurement including mounting the bearing on a vibration tester, the outer ring clamped preventing rotation, mounting a sensor proximate the outer ring to measure vibration, the bearing inner ring rotated to excavate eigen-frequencies, the measured vibration data transmitted from the sensor to a computer workstation, the computer workstation performs a numerical FFT transforming data to Frequency Domain, spectral data from the FFT analyzed with the computer workstation, a peak detection algorithm determines the peaks that are the various modes of the outer ring, the modes are sorted and main modes identified, numerical relationship is obtained for each mode between the resonance and preload, the mode relationships are compared to one or more references, a match between the numerical relationships for each mode and the ideally referenced graph modes indicates a correct preload is determined. Also, a system for carrying out the method.

A method of determining bearing preload by vibration measurement including mounting the bearing on a vibration tester, the outer ring clamped preventing rotation, mounting a sensor proximate the outer ring to measure vibration, the bearing inner ring rotated to excavate eigen-frequencies, the measured vibration data transmitted from the sensor to a computer workstation, the computer workstation performs a numerical FFT transforming data to Frequency Domain, spectral data from the FFT analyzed with the computer workstation, a peak detection algorithm determines the peaks that are the various modes of the outer ring, the modes are sorted and main modes identified, numerical relationship is obtained for each mode between the resonance and preload, the mode relationships are compared to one or more references, a match between the numerical relationships for each mode and the ideally referenced graph modes indicates a correct preload is determined. Also, a system for carrying out the method.

Hundreds of thousands of concrete bridges and hundreds of billions of tons of concrete require characterization with time for corrosion. Accordingly, protocols for rapid testing and improved field characterization systems that automatically triangulate electrical resistivity and half-cell corrosion potential measurements would be beneficial allowing discrete/periodic mapping of a structure to be performed as well as addressing testing for asphalt covered concrete. Further, it is the low frequency impedance of rebar in concrete that correlates to corrosion state but these are normally time consuming vulnerable to noise. Hence, it would be beneficial to provide a means of making low frequency electrical resistivity measurements rapidly. Further, prior art techniques for electrical rebar measurements require electrical connection be made to the rebar which increases measurement complexity/disruption/repair/cost even when no corrosion is identified. Beneficially a method of determining the state of a rebar without electrical contact is taught.

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.

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.

An active mechanical waveguide including an ultrasonically-transmissive material and a plurality of reflection points defined along a length of the waveguide may be driven at multiple resonant frequencies to sense environmental conditions, e.g., using tracking of a phase derivative. In addition, frequency-dependent reflectors may be incorporated into an active mechanical waveguide, and a drive frequency may be selected to render the frequency-dependent reflectors substantially transparent.

An active mechanical waveguide including an ultrasonically-transmissive material and a plurality of reflection points defined along a length of the waveguide may be driven at multiple resonant frequencies to sense environmental conditions, e.g., using tracking of a phase derivative. In addition, frequency-dependent reflectors may be incorporated into an active mechanical waveguide, and a drive frequency may be selected to render the frequency-dependent reflectors substantially transparent.

Hundreds of thousands of concrete bridges, buildings etc. and hundreds of billions of tons of concrete require characterization throughout the process from manufacture to pouring and curing and on throughout service life. The characterization may relate to initial concrete properties, projected concrete properties, framework removal, corrosion, failure etc. Accordingly, a variety of measurements such as water content, electrical resistivity, and half-cell corrosion potential for example would be beneficially implemented as easy to use field test equipment or embedded sensors allowing lifetime monitoring to be performed rather than discrete assessments when issues become evident.