Estimation of the Longitudinal Elasticity Modulus of Braided Synthetic Fiber Rope Utilizing Classical Laminate Theory with the Unit N/tex

Vannei Sry,Akira Todoroki,Gen Endo,Yoshiro Suzuki,Yoshihiro Mizutani

doi:10.3390/app8071096

Abstract

This paper uses classical laminate theory (CLT) and experimental methods to predict the longitudinal specific modulus of braided high modulus polyethylene (HMPE) rope without a matrix. When applying conventional CLT, the modulus, braided angle of strand, and packing factor (PF), i.e., the cross-sectional area ratio of the strand to the rope, are required. Because the void (space between strands) and PF of braided rope without a matrix readily change during the application of load, and given the difficulty measuring PF experimentally, it is difficult to predict the modulus by conventional CLT. This paper proposes the use of the unit of N/tex in place of conventional MPa for CLT. This study demonstrates that changes in PF due to void changes can be neglected when using the N/tex unit. The predicted longitudinal specific modulus of the rope using N/tex unit was found to be in qualitatively agreement with the longitudinal modulus measured experimentally.

Highlights

High strength, high modulus, low elongation, and lightweight synthetic fibers such as high modulus polyethylene (HMPE) and aramid have become promising materials to produce ropes for engineering applications
The specific modulus of the rope was predicted from the specific modulus of the strand in the axial direction and the braided angle of the strand using classical laminate theory (CLT)
The predicted longitudinal specific modulus (E011 ) of the unit cell were compared with that of the rope obtained from the experiment

Summary

Introduction

High modulus, low elongation, and lightweight synthetic fibers such as high modulus polyethylene (HMPE) and aramid (such as Kevlar) have become promising materials to produce ropes for engineering applications. Applications of these types of synthetic fiber ropes have emerged in robotics, such as tendon-driven [1,2,3], active endoscope [4], and artificial muscle [5]. Several researchers have studied the mechanical properties of braided composite materials composed of synthetic fibers and epoxy [8,9,10,11,12,13].

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