A torsional fatigue testing apparatus comprises: a cable holding device, a motion guiding device and a driving device. The cable holding device is provided for holding a cable to be tested to extend between a rotatable holder and a slidable holder. The motion guiding device is provided for converting the rotational motion of the driving device into a reciprocating linear sliding motion by means of linkage so as to alternately rotate the rotatable holder forwardly and reversely, and therefore to repeatedly twist, by the rotatable holder, the cable to be tested.

The invention relates to a method for selecting a viscoelastic plastic interlayer including two outer layers and a central layer that can be incorporated between two glass sheets of a glazing unit, the method includes providing first and second components that constitute respectively the central layer and the outer layers, measuring the shear modulus G′ of the first and second components, selecting the material of the second component only if G′≧3×10.sup.7 Pa at 20° C. and between 100 Hz and 240 Hz, and setting the thickness h of the first component so that h is between 0.31 mm and 1.20 mm and so that g=G′/h is between 5.58×10.sup.8 Pa/m and 2.37×10.sup.9 Pa/m at 20° C. and between 100 Hz and 240 Hz.

The invention relates to a method for selecting a viscoelastic plastic interlayer including two outer layers and a central layer that can be incorporated between two glass sheets of a glazing unit, the method includes providing first and second components that constitute respectively the central layer and the outer layers, measuring the shear modulus G′ of the first and second components, selecting the material of the second component only if G′≧3×10.sup.7 Pa at 20° C. and between 100 Hz and 240 Hz, and setting the thickness h of the first component so that h is between 0.31 mm and 1.20 mm and so that g=G′/h is between 5.58×10.sup.8 Pa/m and 2.37×10.sup.9 Pa/m at 20° C. and between 100 Hz and 240 Hz.

An error compensation system and method may include applying a mechanical load to a reference sample to obtain a load measurement signal from the load sensor and a displacement measurement signal from the displacement sensor, calculating a transfer function to create a load filter and a displacement filter to be applied to the load measurement signal and the displacement measurement signal, respectively, applying the load filter to the load measurement signal to calculate a load compensation value, and applying the displacement filter to the displacement measurement signal to calculate a displacement compensation value, and determining the compensated value by comparing the load compensation value with the displacement compensation value, wherein the compensated value is determined prior to testing a specimen so that the compensated value is used to automatically correct a measured deflection of the specimen to arrive at an actual specimen deflection.

An error compensation system and method may include applying a mechanical load to a reference sample to obtain a load measurement signal from the load sensor and a displacement measurement signal from the displacement sensor, calculating a transfer function to create a load filter and a displacement filter to be applied to the load measurement signal and the displacement measurement signal, respectively, applying the load filter to the load measurement signal to calculate a load compensation value, and applying the displacement filter to the displacement measurement signal to calculate a displacement compensation value, and determining the compensated value by comparing the load compensation value with the displacement compensation value, wherein the compensated value is determined prior to testing a specimen so that the compensated value is used to automatically correct a measured deflection of the specimen to arrive at an actual specimen deflection.

A method for testing an arresting unit (15) for locking a foldable wing tip portion (11) to a wing (5) that includes a fixed wing (9), a foldable wing tip portion (11), and a folded position, an actuation unit (13) for actuating movement of the foldable wing tip portion (11), and an arresting unit (15) for locking the foldable wing tip portion (11). The method includes: locking the foldable wing tip portion (11) in the extended position by the arresting unit (15), controlling the actuation unit (13) to move the foldable wing tip portion (11) in the direction towards the folded position, such that the foldable wing tip portion (11) urges against the arresting unit (15) with a predefined test load, detecting deformation of the arresting unit (15) during or after application of the test load, and comparing the detected deformation to a predefined threshold deformation.

A method for testing an arresting unit (15) for locking a foldable wing tip portion (11) to a wing (5) that includes a fixed wing (9), a foldable wing tip portion (11), and a folded position, an actuation unit (13) for actuating movement of the foldable wing tip portion (11), and an arresting unit (15) for locking the foldable wing tip portion (11). The method includes: locking the foldable wing tip portion (11) in the extended position by the arresting unit (15), controlling the actuation unit (13) to move the foldable wing tip portion (11) in the direction towards the folded position, such that the foldable wing tip portion (11) urges against the arresting unit (15) with a predefined test load, detecting deformation of the arresting unit (15) during or after application of the test load, and comparing the detected deformation to a predefined threshold deformation.

A system can include a torsion applicator (e.g., a torsion motor and shaft) configured to apply a torque to a test article that is additively built on and attached to a build plate. The system can include at least one twist sensor and at least one torque sensor. A method for determining quality of an additively manufactured article or batch thereof can include torsion testing at least one additively manufactured test article that is built on and attached to a build plate while the at least one test article is still attached to the build plate.

A method and apparatus for rotating a test specimen and simultaneously applying a torque, bending moment, and an axial load without the applied forces interfering with each other.

A method and apparatus for rotating a test specimen and simultaneously applying a torque, bending moment, and an axial load without the applied forces interfering with each other.