Enhance energy absorption of hollow-cylinder rubber fender using V-notch ring grooves

Abstract

A method was proposed for enhancing the energy absorption of hollow-cylinder rubber (HCR) fenders by introducing V-notch ring grooves at the top and bottom of the fender structure. The feasibility of the proposed approach was investigated experimentally by compression tests on scaled HCR fenders with four notch height positions (6, 8, 10, and 12 mm) and two notch depths (2 and 3 mm), and the tests were conducted within the strain range 0 to −0.6. The effects of the V-notch ring grooves on the stress, strain, and energy absorption of the fender were examined first. Then, the influences of the V-notch position and depth on the buckling strength, buckling strength, and compression toughness of the fender were studied. Next, the impact of the V-notch ring grooves on the energy absorption of the fender was analyzed in terms of three properties, including the energy absorption index, the energy absorption efficiency index, and the mooring index. Finally, the practical performance of different V-notch ring groove configurations was evaluated by comparing the compression toughness of the notched fenders at the rated stress with that of an un-notched fender. It is shown that the V-notch ring grooves with a depth of 2 mm located at 6 mm from the top and bottom of the HCR fender can improve the compression toughness by 4%. This study concluded by deriving fourth- and fifth-order polynomial equations to predict the stress-strain and stress-energy absorption response of the un-notched and notched fenders over the compressive strain range from zero to −0.6.