Effect of Wall Thickness on Stress–Strain Response and Buckling Behavior of Hollow-Cylinder Rubber Fenders

Abstract

In this study, the effect of wall thickness (15–25 mm) on the stress–strain response of hollow-cylinder rubber fenders were investigated by conducting monotonic compression tests. It was found that a progressive increase in lateral bending deformation was observed during monotonic compression. Simultaneously, the extent of the lateral deflection decreased notably with an increasing wall thickness. From the experimental results, the fact is accepted that buckling occurred in the tested fender due to the fact that the ratio of the height to the wall thickness was higher than four in all of the considered cases. Moreover, an s-shape profile appeared in the stress–strain curves, which became clearer as the wall thickness was reduced from 25 to 15 mm. To assess the performance of fenders objectively, an energy-effectiveness index, C E R , was introduced to quantify the energy absorption capacity of the fender. From the experimental observations, it was inferred that the contact area of the folded inner surface of the fender produced under compression generated an additional reaction force and affected the shape of the stress–strain curve since the measured load consisted of two reaction forces: one caused by the self-contact area, and the other resulted from the compression-bending deformation that occurred in the side wall of the fender. To examine this assertion, a finite element analysis (FEA) was conducted and confirmed the effect of the reaction force on the sensitivity of the s-shape characteristic of the stress–strain curve. Finally, a polynomial regression was conducted and the calculated results based on the fourth-degree stress polynomial function correlated very well with the measured stress–strain curves.

High-Accuracy and Fast Calculation Framework for Berthing Collision Force of Docks Based on Surrogate Models

“…It is worth mentioning that the berthing angle here is the angle between the berthing speed in the direction of ship navigation and the perpendicular line of the dock. The energy absorption capacity of rubber fenders is primarily determined by the stress-strain relationship of the material [23,24]. Given that a ship may encounter multiple rubber fenders during berthing, it is assumed that each individual fender undergoes elastic deformation when compressed.…”

Straight and Bent Bars Buckling Considered as the Axial Displacement of One Bar End

“…By knowing the sinusoid equation, we can determine the elastic energy US accumulated in the bar (Shen et al, 2020):…”

“…Buckling is a classic mechanical problem, the concept of which was introduced by Euler (Euler, 1744). Over the years, buckling analysis has found wide application, including in civil engineering (Śledziewski & Górecki, 2020;Toledo et al, 2020), mechanical engineering (Czechowski et al, 2020;Kubit et al, 2019) or the maritime industry (Corigliano et al, 2019;Shen et al, 2020). Currently, there is a renewed interest in buckling, in particular in applications in composite structures (Rozylo et al, 2020;Schilling & Mittelstedt, 2020;Xu & Wu, 2008) or micro and nano technologies (Barretta et al, 2019;Chandra et al, 2020).…”

Comparative Analysis of NR/EPDM Ratio and Carbon Black Selection on Mechanical Properties of Vulcanized Pneumatic Fenders

“…They are typically cylindrical or cylindrical-shaped rubber structures filled with compressed air. These Fenders are designed to absorb kinetic energy during vessel berthing or mooring, thereby reducing the impact force, and preventing damage to both the vessel and the docking facility [1][2] . The inner and outer parts of the pneumatic fender work together to absorb and distribute the impact energy.…”