Q1: What is a rubber shear radial apparatus used for?
A rubber shear radial apparatus is used to study the torsional shear behaviour of a rubber cylinder under applied torque. Students apply incremental loads, measure the resulting angle of rotation from the graduated disc, and use those values to determine the shear stress, shear strain, and modulus of rigidity of the rubber specimen.
Q2: How is the angle of rotation measured in the FX-501?
The FX-501 uses a round graduated plate marked from 0° to 360°, mounted on the free (upper) aluminium plate and fitted with a fixed pointer. As torque is applied via the weighted thread, the upper plate rotates and the pointer indicates the angle of rotation directly on the scale — no external measuring instruments are required.
Q3: What is the difference between the FX-500 and FX-501 rubber shear apparatus?
The FX-500 applies a linear (direct) shear load to a rectangular rubber block and measures linear deflection using a dial gauge. The FX-501 applies a torsional (radial) shear load to a cylindrical rubber block and measures angular rotation using a graduated disc. Both units investigate the modulus of rigidity and hysteresis, but under different loading modes.
Q4: Why does the FX-501 use a cylindrical rubber block instead of a rectangular one?
A cylindrical geometry is appropriate for torsional loading because the circular cross-section distributes shear stress uniformly around the axis of rotation. This makes the calculation of shear stress and the modulus of rigidity more straightforward and consistent with standard torsion theory applied to solid circular sections.
Q5: What is included in the scope of delivery for the FX-501?
The FX-501 is supplied as a complete experimental kit including: one experimental unit (rubber cylinder bonded between aluminium alloy plates, graduated round disc with pointer, and HDF wall mounting), one thread for torque application, one set of calibrated weights (1 x 1 N hanger, 4 x 2 kg, 1 x 1 kg), and one instructional manual covering experimental procedures and data recording.