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.

Exemplary embodiments are directed to instrumented fasteners and associated damage detection systems for detecting damage in an assembled structure secured together by at least one instrumented fastener. The instrumented fastener forms a transducer assembly for detecting damage in the assembled structure. The fastener can include a cavity disposed at one end of the fastener. The transducer assembly includes an electromechanical unit at least partially inserted into and mechanically coupled within the cavity of the fastener. The electromechanical unit can include a piezoelectric element.

A rock breaking device and a method of monitoring a condition of a tool of a rock breaking device is provided. The rock breaking device includes a frame, a tool, a device for generating stress waves in the tool, measuring means for measuring the stress wave propagating in the tool and at least one computing unit for monitoring a condition of the tool on the basis of the measured stress wave. The at least one computing unit is configured to determine a condition of the tool on the basis of a time of propagation of at least one reflected stress wave component of the stress wave and at least one additional property of the same reflected stress wave component.

A bolt axial force measurement method of the present invention includes: a probe insertion step of inserting a stepped protrusion of a probe into a stepped recess formed in a head of a bolt, the stepped protrusion being included in a probe to correspond to the stepped recess of the head; an elongation calculation step of calculating an elongation of the bolt during tightening, based on a bottom echo of an ultrasonic pulse emitted from the probe toward a bottom face of a shank of the bolt; and an axial force calculation step of calculating an axial force of the bolt, based on the elongation of the bolt.

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.

A portable inspecting device includes PZT transducers and performs active sensing to measure the characteristics of bolted connections. The PZT transducers are mounted on opposing ends of spring-loaded rods and can be moved apart to accommodate a structure for testing. The springs cause the PZT transducers to push against opposing parts of the structure in a stable but temporary fashion. The device can be physically moved to inspect the status and health of multiple different bolted connections.

A system is provided having a probe assembly configured to inspect components of an assembled flange connection when the probe assembly is disposed within a bore of the components. The probe assembly includes a shaft configured to be aligned with an axis of the assembled flange connection, one or more ultrasound probes coupled to the shaft, and one or more encoders. The one or more ultrasound probes are configured to interface with an interior surface of the bore of the components, to emit ultrasound signals into the components, and to receive ultrasound signals from the components. The one or more encoders are coupled to the shaft and are configured to determine a position of the one or more ultrasound probes relative to a reference point of the assembled flange connection during an inspection of components of the assembled flange connection.

An electromagnetic ultrasonic double wave transducer, comprising a shell (1), and a permanent magnet assembly, a coil (4), a shielding layer (5), and a wire (6) which are provided in the shell (1). The permanent magnet assembly comprises a first permanent magnet (2) and a second permanent magnet (3) sleeved on the first permanent magnet (2). The magnetizing directions of the first permanent magnet (2) and the second permanent magnet (3) are perpendicular to the bottom of the shell (1), and the magnetic field directions of the first permanent magnet (2) and the second permanent magnet (3) are opposite. A non-conducting non-magnetic bushing material (9) is provided between the first permanent magnet (2) and the second permanent magnet (3), and upper end faces of the first permanent magnet (2) and the second permanent magnet (3) realize magnetic circuit closing by means of a magnetic circuit closing element (8). The coil (4) is fixed on the bottom of the shell (1) and is located below the first permanent magnet (2). The shielding layer (5) is provided between the lower end of the first permanent magnet (2) and the coil (4) and below the second permanent magnet (3). One end of the wire (6) is connected to the coil (4), and the other end is connected to the power supply and signal plug (7). The electromagnetic ultrasonic double-wave transducer can simultaneously stimulate longitudinal wave and transverse wave on the surface of the part to be inspected, and the inspection accuracy is improved.

A method of monitoring a mechanical connection between a first aircraft component and a second aircraft component. The method includes securing, using a securing device, the first aircraft component to the second aircraft component; obtaining information indicative of an acoustic signal emitted during the securing the first aircraft component to the second aircraft component; and inputting the information indicative of the acoustic signal into a machine learning model. The machine learning model is configured to provide an output indicative of a fault condition of the mechanical connection.

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.