A method for measuring corrosion-expansion force during cracking of concrete due to corrosion and expansion of reinforcing steel; wherein, deformation on a surface of reinforced concrete is photographed based on a digital image correlation (DIC) method, a full-field displacement and a full-field strain on a surface of the concrete are analyzed and calculated, a relationship between corrosion-expansion force and the strain on the surface of the concrete is found through an established theoretical model, and corrosion-expansion force of reinforcing steel and a change rule of the corrosion-expansion force are calculated. Therefore, the method is simple and includes with safe and reliable operations, scientific principles, and low costs, so that a change in corrosion-expansion force during corrosion and expansion of reinforced concrete can be monitored in real time.

A computer-implemented method for identifying mechanical parameters of an object subjected to mechanical stress is provided. The method comprises a step of acquiring, by an imaging means, images of the object taken before and during the application of the mechanical stress, three steps of calculating the effects due to the stress carried out either on the basis of the modeling of the recorded images or on the basis of a theoretical mechanical modeling of the stress, a step of defining a functional equal to the difference between the two models and a last step of minimizing said functional so that the experimental model is as close as possible to the theoretical mechanical model. Additional measurements make it possible to refine the method.

An in-situ bollard tester. The in-situ bollard tester may comprise: a frame, cable, and tensioner. The frame is preferably adapted to mount onto a pier or wharf and around a bollard to provide structural support for the cable and tensioner. The frame may comprise a rectangular frame, pair of hanging columns, and first and second pair of legs. The first pair of legs are coupled near proximal corners of the rectangular frame and are vertically disposed. The hanging columns are coupled near distal corners of the rectangular frame. The second pair of legs are coupled at the lower ends of the hanging columns and are disposed in a horizontal manner. The tensioner may be coupled above the rectangular frame. The cable may fasten to the bollard, and the tensioner may apply tension to the cable at various load angles in order to test the integrity of the bollard.

The present invention relates to a system for synchronous monitoring of multi-point displacement and rotation responses of a large structure, and a data analysis method therefor, and belongs to the technical field of structural health monitoring engineering. The system includes a laser sensor and a laser receiver. A laser device is disposed inside the laser sensor and is capable of emitting laser, and laser emitted by the laser device is received by the laser receiver. The displacement and rotation responses at a monitoring point of the large structure drive displacement and pointing direction of laser produced by the laser sensor to change, and the change is received by an internal measurement system of the laser receiver. The displacement and rotation responses at the monitoring point of the large structure can be inversely calculated based on internal measurement data of the laser receiver according to the data analysis method for the system for synchronous monitoring of the multi-point displacement and rotation responses of the large structure provided by the present invention. By means of the system for synchronous monitoring of the multi-point displacement and rotation responses of the large structure, long-term real-time monitoring of multi-point displacement of large civil engineering structures such as bridges, tunnels and high-rise buildings can be realized.

A system and method for monitoring conditions in a crawl space is provided. The system generally comprises at least one sensor, computing device, data aggregator operably connected to the at least one sensor, processor operably connected to the computing device, power supply, and non-transitory computer-readable medium coupled to the processor and having instructions stored thereon. The system is designed to collect condition data via the at least one sensor and determine whether the conditions within the crawl space could have a detrimental impact on the building. In particular, the system is designed to monitor settling of a building over time and alert a user if the settling exceeds a predefined threshold.

The present disclosure provides an automatic test system for actual stress of a bridge based on DIC technology, where the system includes a camera, a phosphor spraying device, a computer, and a sliding rail; the sliding rail is arranged on both sides of an upper wing of a box-shaped concrete beam; the phosphor spraying device is used to spray phosphor on a web of the box-shaped concrete beam to form speckles of varying light and shade; the camera is slidably connected to the sliding rail through a bracket, and is used to photograph the speckles and transmit a speckle image to the computer; and the computer is used to analyze and process the speckle image taken by the camera and generate a time history diagram of stress.

A measurement method includes generating first displacement data based on data of observation points of a structural object, generating observation information, calculating deflection amounts of the structural object by vehicles of a moving object, calculating approach times and exit times of the vehicles with respect to the structural object, calculating time intervals divided by a plurality of times obtained by sorting the approach times and the exit times by time, calculating an amplitude amount of the first displacement data in each of the time intervals, calculating an amplitude amount of the deflection amount in each of the time intervals, and calculating weighting coefficients assuming that a sum of products of the amplitude amounts of the deflection amounts in the time intervals and the weighting coefficients to the vehicles is equal to the amplitude amount of the first displacement data in the time intervals.

An apparatus includes an acquisition means for acquiring displacement quantity in a time-series manner, the displacement quantity being generated at a measurement part of a structure by the weight of a vehicle that travels on the structure, a detection means for detecting the size of the vehicle that passes through the structure and detecting the type of the vehicle from the size, and a control means for controlling the acquisition means on the basis of the detected type of the vehicle.

A racquet including a frame including a head portion, a handle portion, and a throat portion. The head portion is a tubular structure including inner and outer peripheral walls, each having inner and outer surfaces. The head portion of the racquet being formed of a fiber composite material. The fiber composite material includes a plurality of ply arrangements. Each includes a pair of plies defining first and second angles with respect to a composite axis. A section of the outer peripheral wall from the inner surface to the outer surface includes at least three ply arrangements overlaying each other, and the first and second angles of at least two of the at least three ply arrangements being at least 35 degrees. When the racquet is tested under a racquet torsional stability test, the racquet has an angular deflection of less than 5.5 degrees about a longitudinal axis.

An inspection apparatus includes: a plurality of support members that support a display panel at a predetermined height; a bending-pressing member that presses a pressing surface of the display panel; a sound wave sensor that senses a sound wave generated from the display panel during a bending inspection process, wherein during the bending inspection process, the bending-pressing member presses the pressing surface of the display panel; and an inspection controller that detects a crack in the display panel using the sound wave sensed by the sound wave sensor.