A method for determining the prestress force of a connection component (10) is proposed. In the method, ultrasonic signals (22) are introduced into the connection component (10) and ultrasonic echoes (24) of the ultrasonic signals (22) are received again. The method comprises the following steps: a) introducing a longitudinal ultrasonic signal and determining a first signal time of flight FTOF.sub.L of the longitudinal ultrasonic signal until the reception of an echo of the longitudinal ultrasonic signal, b) introducing a transverse ultrasonic signal and determining a second signal time of flight FTOF.sub.T of the transverse ultrasonic signal until the reception of an echo of the transverse ultrasonic signal, and c) determining an effective temperature T.sub.eff and the prestress force of the connection component (10) on the basis of the first signal time of flight FTOF.sub.L, the second signal time of flight FTOF.sub.T, previously determined reference data and calibration factors using the assumption that a prestress force F.sub.L ascertained using the first signal time of flight FTOF.sub.L and a prestress force F.sub.T ascertained using the second signal time of flight FTOF.sub.T are equal in magnitude,
wherein steps a) and b) are carried out successively in any desired order or in parallel. A further aspect of the invention relates to a device for carrying out the method.

An ultrasound transmitting and receiving device that can determine whether a contact state between a probe and a bolt is normal without relying on the skill of an operator is provided. The ultrasound transmitting and receiving device includes a probe control unit, an auxiliary storage device, and a contact state determination unit. The probe control unit causes a probe to transmit ultrasound to a bolt, and causes the probe to receive an echo of the transmitted ultrasound. The auxiliary storage device stores one or more pieces of comparison data to be compared with echo data indicating the echo received by the probe. The contact state determination unit compares the echo data with the comparison data, and determines a contact state between the probe and the bolt based on a comparison result.

A bolt includes a head portion on which a recess is formed. The recess has a bottom surface and a sidewall extending from a periphery of the bottom surface. The sidewall has a lower end defined by the bottom surface and includes an increased diameter portion and a reduced diameter portion. The increased diameter portion has an inner diameter larger than an inner diameter of the lower end of the side wall. The reduced diameter portion has an inner diameter smaller than the inner diameter of the increased diameter portion. The reduced diameter portion is located opposite to the bottom surface across the increased diameter portion.

An ultrasound transmitting and receiving device that can determine whether a contact state between a probe and a bolt is normal without relying on the skill of an operator is provided. The ultrasound transmitting and receiving device includes a probe control unit, an auxiliary storage device, and a contact state determination unit. The probe control unit causes a probe to transmit ultrasound to a bolt, and causes the probe to receive an echo of the transmitted ultrasound. The auxiliary storage device stores one or more pieces of comparison data to be compared with echo data indicating the echo received by the probe. The contact state determination unit compares the echo data with the comparison data, and determines a contact state between the probe and the bolt based on a comparison result.

Disclosed is a dual channel nondestructive testing method for a rock bolt and related devices. The method includes: determining a target phase difference and an instantaneous phase difference of the first received signal and the second received signal; determining an integral instantaneous phase difference between the first received signal and the second received signal based on the target phase difference and an instantaneous phase difference; determining a length of the exposed section of the rock bolt, a length of the rock bolt and a position of a grouting defect based on the integral instantaneous phase difference, a first velocity of the acoustic signal propagating in an exposed section of the rock bolt and a second velocity of the acoustic signal propagating in an anchor section of the rock bolt.

The use of nondestructive inspection (NDI) capabilities for the detection of fatigue cracks extending from fastener holes in multi-layered metallic structures without removing the fastener; including at least the use of a probe guide containing a UT sensor and either an inertial measurement unit (IMU) or a rotary encoder, and either of these options could be applied in testing of either raised head fasteners or flush fasteners.

A tester for evaluating pullout load capacity and bond quality of anchor bolts embedded in concrete includes a Schmidt hammer for measuring a rebound number and an ultrasonic pulse velocity tester for measuring the transit time of a pulse transmitted through concrete surrounding an anchor bolt. The rebound number and the transit time are combined and matched against a database record which identifies the pullout load capacity and the bond quality. The transit time is matched to thresholds of transit times associated with porosity, internal cracking, air voids, and water pockets located around the embedded anchor bolt. The Schmidt hammer is further modified by the incorporation of a digital level for measuring the vertical and horizontal angles of inclination of the plunger with the concrete surface, a guide tube for supporting the plunger, and by using a convex plunger tip for improved registration with anchor bolt head.

In one aspect, a method of determining a parameter of a fastener includes providing an input to an ultrasonic transducer of a transducer arrangement, wherein the transducer is attached to a fastener and the input results in the transmission of an ultrasonic wave into the fastener. A transducer output is received, which is indicative of a reflected ultrasonic wave received by the transducer. The transducer output is compared to known data for the parameter to determine whether the parameter of the fastener is within a predetermined range.

The invention relates to a solution for how to measure the strain in a washer mounted in a bolt assembly comprising a bolt, nut and washer. The invention concerns a strain measuring washer assembly comprising a plate shaped washer body, sound emitting means and sound detecting means, and a method for using such.

An arrangement for non-destructive testing of a component part, which may include a first end surface and a second opposite end surface. The arrangement may include a plurality of discrete piezoelectric transduction elements arranged in a circular array on the first end surface, and an electric wave signal transmitting and receiving unit electrically coupled to the piezoelectric transduction elements. The electric wave signal transmitting and receiving unit may be able to generate an electric excitation wave signal and to receive an electric response wave signal. The piezoelectric transduction elements may deform, upon an application of the electric excitation wave signal, in an in-phase shearing motion parallel to the first end surface and in respective tangential direction with respect to the circular array so as to generate a corresponding structure-borne wave in the component part at the first end surface such that said structure-borne wave can propagate in the component part.