An example hinged device flexible substrate testing system includes: a first plate comprising a first surface configured to hold stationary a first side of a hinged device under test; a second plate comprising a second surface configured to hold a second side of the hinged device under test; a first cam follower coupled to the second plate; a first drive arm configured to move the first cam follower to cause the second plate to rotate about a hinge pivot axis of the hinged device under test; an actuator configured to rotate the drive arm; and a load cell configured to measure loads on the first plate while the actuator moves the second plate.

An example hinged device flexible substrate testing system includes: a first plate comprising a first surface configured to hold stationary a first side of a hinged device under test; a second plate comprising a second surface configured to hold a second side of the hinged device under test; a first cam follower coupled to the second plate; a first drive arm configured to move the first cam follower to cause the second plate to rotate about a hinge pivot axis of the hinged device under test; an actuator configured to rotate the drive arm; and a load cell configured to measure loads on the first plate while the actuator moves the second plate.

A three-dimensional dynamic and static load test system for simulating deep roadway excavation and a method thereof are provided, which relates to the technical field of indoor simulation testing in underground engineering. The system includes a mobile platform, a box body, a support frame, a roadway excavation device, and a data monitoring unit. The system and method of the disclosure can reproduce the whole process of roadway excavation, simulate the multi-directional loading of deep roadway, and restore the real stress state of deep roadway under the influence of dynamic and static load superimposed disturbance. The problem of insufficient research under the condition of unidirectional static loading and lack of multi-directional dynamic and static loading in current large-scale experimental devices has been solved, and the stress and deformation of the surrounding rock of the roadway are reflected in real-time through the data monitoring unit.

A three-dimensional dynamic and static load test system for simulating deep roadway excavation and a method thereof are provided, which relates to the technical field of indoor simulation testing in underground engineering. The system includes a mobile platform, a box body, a support frame, a roadway excavation device, and a data monitoring unit. The system and method of the disclosure can reproduce the whole process of roadway excavation, simulate the multi-directional loading of deep roadway, and restore the real stress state of deep roadway under the influence of dynamic and static load superimposed disturbance. The problem of insufficient research under the condition of unidirectional static loading and lack of multi-directional dynamic and static loading in current large-scale experimental devices has been solved, and the stress and deformation of the surrounding rock of the roadway are reflected in real-time through the data monitoring unit.

An equivalent test method of a piston vibrating machine and a rocker-arm vibrating machine applied in half breakdown time test, including: selecting three grades of samples in the same size specification; separately selecting frequencies of the piston vibrating machine and the rocker-arm vibrating machine; estimating impact times of the two vibrating machines for three grades of samples; setting up the impact times and separately impacting the samples with the two vibrating machines; sieving and weighing the impacted samples and obtaining the unbroken ratios; calculating impact cycles with an unbroken ratio of 50%; calculating the ratios of the impact cycles of the two vibrating machines for the samples; calculating an average of the ratios; calculating the relative percentages of impact cycle ratios for the three grades and assessing the linearity of the samples; and calculating equivalent impact cycles of the vibrating machines.

An equivalent test method of a piston vibrating machine and a rocker-arm vibrating machine applied in half breakdown time test, including: selecting three grades of samples in the same size specification; separately selecting frequencies of the piston vibrating machine and the rocker-arm vibrating machine; estimating impact times of the two vibrating machines for three grades of samples; setting up the impact times and separately impacting the samples with the two vibrating machines; sieving and weighing the impacted samples and obtaining the unbroken ratios; calculating impact cycles with an unbroken ratio of 50%; calculating the ratios of the impact cycles of the two vibrating machines for the samples; calculating an average of the ratios; calculating the relative percentages of impact cycle ratios for the three grades and assessing the linearity of the samples; and calculating equivalent impact cycles of the vibrating machines.

Disclosed herein are ropes containing bundles of filaments, where each bundle includes at least 70% by volume of liquid crystal polymer filaments, and where at least one bundle includes liquid crystal polymer filaments of at least 10 denier per filament in size. Also disclosed herein are methods of pulling or lifting an object by applying tension to such a rope connected to the object, where the rope is arranged over a sheave or a non-rotating guide surface, and a ratio of a diameter of the sheave or an effective diameter of the non-rotating guide surface, D, to a diameter of the rope, d, is at least 20:1.

A method for detecting a failure condition in one or more components of a wind turbine is provided. The method includes actuating, via a controller, an impact device to generate a vibration having a vibration frequency and a vibration magnitude in the one or more components. The method further includes receiving data indicative of the vibration frequency and the vibration magnitude from a sensor communicatively coupled to the controller. The method further includes determining, via the controller, whether the data indicative of the vibration frequency and/or the vibration magnitude is outside of a predetermined vibration range for the one or more components.

A method for detecting a failure condition in one or more components of a wind turbine is provided. The method includes actuating, via a controller, an impact device to generate a vibration having a vibration frequency and a vibration magnitude in the one or more components. The method further includes receiving data indicative of the vibration frequency and the vibration magnitude from a sensor communicatively coupled to the controller. The method further includes determining, via the controller, whether the data indicative of the vibration frequency and/or the vibration magnitude is outside of a predetermined vibration range for the one or more components.

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.