The Effects of Strain Rates on Mechanical Properties and Failure Behavior of Long Glass Fiber Reinforced Thermoplastic Composites

Abstract

Long glass fiber reinforced thermoplastic composites have been increasingly used in automotive parts due to their excellent mechanical properties and recyclability. However, the effects of strain rates on the mechanical properties and failure mechanisms of long glass fiber reinforced polypropylene composites (LGFRPPs) have not been studied systematically. In this study, the effects of strain rates (from 0.001 s−1 to 400 s−1) on the mechanical properties and failure mechanism of LGFRPPs were investigated. The results showed that ultimate strength and fracture strain of the LGFRPPs increased obviously, whereas the stiffness remained essentially unchanged with the strain rates from low to high. The micro-failure modes mainly consisted of fibers pulled out, fiber breakage, interfacial debonding, matrix cracking, and ductile to brittle (ductile pulling of fibrils/micro-fibrils) fracture behavior of the matrix. As the strain rates increased, the interfacial bonding properties of LGFRPPs increased, resulting in a gradual increase of fiber breakage at the fracture surface of the specimen and the gradual decrease of pull-out. In this process, more failure energy was absorbed, thus, the ultimate strength and fracture strain of LGFRPPs were improved.

Interlayer Bonding Capability of Additively Manufactured Polymer Structures under High Strain Rate Tensile and Shear Loading

“…The fracture surface with high magnification demonstrates the additional failure mechanism of fiber pull-out. These failure mechanisms under high strain rates are consistent with current literature [ 36 ]. Furthermore, the internal quality is represented by visible voids.…”

Microstructure and Properties of Glass Fiber-Reinforced Polyamide/Nylon Microcellular Foamed Composites

“…The interface of each fiber and the matrix can refine the crack and cause it to propagate in multiple directions, thus extending the propagation length. The fracture in the GF/PA changes from a single-matrix fracture to a combined of matrix fracture, fiber pullout, and fiber broken, which helps increase the mechanical toughness [ 17 , 18 , 19 ]. GF/PA microcellular foamed composites have the characteristics of high strength and the advantages of being lightweight as well as having a low production cost and high product dimensional accuracy, because the addition of fibers could promote nucleation, refining the cell structure [ 20 ].…”

Investigation of Mode I and Mode I/II Fracture Behavior at Different Deformation Rates of Fiber Reinforced Composites

“…Çalışmalarında 0,005 s -1 , 0,0005 s -1 ve 0,00005 s -1 deformasyon hızlarını kullanmışlardır. Yapılan başka bir çalışmada J. Cui ve arkadaşları [7] uzun fiberli polimer kompozit malzemelerin mekanik ve hasar davranışlarını düşük deformasyon hızlarında (0,001 ve 0,01 s -1 ) ve yüksek deformasyon hızlarında (1, 10, 100, 200 ve 400 s -1 ) incelemişlerdir. Z. Jia ve arkadaşları [8] poliüretan yapıştırıcının farklı yükleme hızlarında (0,5mm/dk., 50mm/dk., 500mm/dk.)…”