Effects of gelcoat thickness on mechanical properties of woven glass/polyester laminated composite

Abstract

In this study, effects of gelcoat thickness on the mechanical properties and interfacial bonding of woven glass/polyester laminated composite are investigated by using threepoint flexural test and tensile test. The composites had been applied at variance thickness of gelcoat layers (0.25, 0.3, 0.35, 0.4, 0.45, and 0.5mm) using hand lay-up method. Samples were measured in two techniques for the flexural test, i.e., coated surface facing the loads (concave) and bare surface facing the loads (convex). Since the coated surface was concavely bent, greatest increase of flexural strength that acquired 5fold of increase was shown by composite with 0.3 mm of gelcoat thickness for both measurements. The increasing of thickness to 0.35 mm and above deflated the rising percentage in flexural strength. This event was happened because of the gelcoat thickness ratio was greater than the matrix/reinforcement ratio. For tensile test, composite applied with gelcoat of 0.4 mm thickness exhibited the highest increase in strength. An increase of almost 38 % in tensile strength was recorded compared to the uncoated composite. Similarly, the increase in tensile strength reduced slightly when the gelcoat thickness was increased above 0.4 mm. The results demonstrate that the mechanical properties of the composite improve as the gelcoat thickness increases. However, the mechanical properties show no further improvement as the thickness is further increased above the optimum thickness.

A comprehensive review on plant‐based natural fiber reinforced polymer composites: Fabrication, properties, and applications

“…[128,129] In flax preform reinforced epoxy composites, an increase in the fiber volume percentage improved the tensile strength and young's modulus while decreasing the compressive strength. [130,131] Banana fibers treated with sodium hydroxide (NaOH) showed lesser water absorption and increased tensile strength due to better fiber-matrix interlocking. The optimum volume fraction of banana fiber in the epoxy is observed as 40 wt% for optimum mechanical properties.…”

Composite Material Damage Processes

“…Although it consists mainly of a matrix, as the most exposed laminate layer, in some cases it can be significantly subjected to external loads and it is not advisable to neglect cracks and damage that might appear in gelcoat. The thickness of the gelcoat layer has significant role in surface appearance and also the performance of the laminate [34]. Its performance can be enhanced by adding the nanoparticles [35] or other additives and structural strength of the gelcoat can be increased.…”

A Review of Natural Fiber-Reinforced Composites for Lower-Limb Prosthetic Designs

“…Recent advances in natural fiber-reinforced composites (NFRCs) have demonstrated good mechanical and ecological properties compared with synthetic fibers (such as carbon and glass fibers), while also being economically accessible and abundant [29][30][31][32][33][34]. To mention a few, fibers such as kenaf [8,[35][36][37], jute [38], ramie [39], and hemp [40] have highlighted their mechanical performance and versatility, comparing favorably against synthetic fibers in terms of their mechanical properties and common applications.…”

“…Sustainability and Environmental Friendliness: Natural fibers used as composite reinforcements, such as kenaf and flax, are renewable resources that provide a sustainable alternative to synthetic fibers [8,[29][30][31][32][33][35][36][37]98,119]. The utilization of natural composites in prosthetic design aligns with the increasing demand for eco-friendly materials and reduces the reliance on non-renewable resources.…”