Simulations and Tests of Composite Marine Structures Under Low-Velocity Impact

Zhaoyi Zhu,Yunfeng Xiong,Qinglin Chen,Xiaowen Li,Yingqiang Cai

doi:10.2478/pomr-2021-0006

Abstract

Abstract Due to their excellent performance, composite materials are increasingly used in the marine field. It is of great importance to study the low-velocity impact performance of composite laminates to ensure the operational safety of composite ship structures. Herein, low-velocity drop-weight impact tests were carried out on 12 types of GRP laminates with different layup forms. The impact-induced mechanical response characteristics of the GRP laminates were obtained. Based on the damage model and stiffness degradation criterion of the composite laminates, a low-velocity impact simulation model was proposed by writing a VUMAT subroutine and using the 3D Hashin failure criterion and the cohesive zone model. The fibre failure, matrix failure and interlaminar failure of the composite structures could be determined by this model. The predicted mechanical behaviours of the composite laminates with different layup forms were verified through comparisons with the impact test results, which revealed that the simulation model can well characterise the low-velocity impact process of the composite laminates. According to the damage morphologies of the impact and back sides, the influence of the different layup forms on the low-velocity impact damage of the GRP laminates was summarised. The layup form had great effects on the damage of the composite laminates. Especially, the outer 2‒3 layers play a major role in the damage of the impact and the back side. For the same impact energy, the damage areas are larger for the back side than for the impact side, and there is a corresponding layup form to minimise the damage area. Through analyses of the time response relationships of impact force, impactor displacement, rebound velocity and absorbed energy, a better layup form of GRP laminates was obtained. Among the 12 plates, the maximum impact force, absorbed energy and damage area of the plate P4 are the smallest, and it has better impact resistance than the others, and can be more in line with the requirements of composite ships. It is beneficial to study the low-velocity impact performance of composite ship structures.

Highlights

Composite laminates are being increasingly used in lightweight structural components for a variety of engineering fields, such as the aerospace, automotive, marine and wind turbine sectors, because of their high strength-to-weight and stiffness-to-weight ratios, good fatigue performance and excellent corrosion resistance [1,2,3]
In the marine engineering field, fibre-reinforced composite materials can be used as hull panels, superstructure, main hull, propellers and fishing tools, etc. [4,5]
These low-velocity impacts often lead to internal damage to the composite hull structure, which cannot be observed by the human eye and severely affects the safety of the hull structure

Summary

INTRODUCTION

Composite laminates are being increasingly used in lightweight structural components for a variety of engineering fields, such as the aerospace, automotive, marine and wind turbine sectors, because of their high strength-to-weight and stiffness-to-weight ratios, good fatigue performance and excellent corrosion resistance [1,2,3]. Considering that mechanical tests require more human effort and material resources, many researchers have begun to use numerical methods to simulate the low-velocity impact process of composite structures. Moura et al [1516] used Abaqus to simulate the low-velocity impact process, and the simulated delamination shape and area were in good agreement with their test results. The numerical study of the low-velocity impact behaviour of laminates is more in-depth in the aerospace field, and the research on marine composite structures needs to be further developed. This study selected a composite yacht structure as the research object, and the mechanical behaviour of composite marine laminates under low-velocity impact was studied through mechanical testing and numerical simulation. The results from this work provide a reference for the study of the low-velocity impact performance of composite ships

EXPERIMENTAL METHOD

CONCLUSION