A pin-on-disc test apparatus was used to investigate the dry sliding wear characteristics of the FRP composites as per ASTM G99-95 standards. The surface of the sample (10 mm× 10 mm×3 mm) glued to mild steel pin of dimensions 6 mm diameter and 27 mm height using a suitable adhesive. The test sample was held in the slot provided at the arm so that it makes surface contact with the disc. The counter surface disc was made of En-32 steel hardened to 62 HRC having dimensions of 165 mm diameter, 8 mm thick with surface roughness (Ra) of 15 μm. The tests were conducted on a track of 110 mm diameter for a sliding distance, applied load and sliding velocity. Prior to testing, the specimens were rubbed over a 600 grade SiC paper to remove any foreign particles on the surface and to ensure proper contact with the counter surface. The surface of both the samples and disc were cleaned with soft cotton soaked in acetone before the test.

My problem is the 10 mm× 10 mm×3 mm is not completely in contact with counter surface disc. So there is a development of apparent contact area. How to fix this problem