Feasibility Analysis of Bolted Joints with Composite Fibre-Reinforced Thermoplastics

The use of composite materials has shown steady growth in recent years due to their excellent specific mechanical properties and the possibility to reduce the weight of vehicles without impairing their safety and comfort. Continuous fibre-reinforced thermoplastic composites (CFRTP) show dynamic, acoustic, and damping properties far superior to steel and can be recycled and repaired. Their excellent properties make CFRTP good candidates for anti-vibration and shock absorbing components, however, out-of-plane mechanical properties hinder the anchoring to the vehicle’s body by means of bolted connections. The results obtained in this study show how the maximum torque that can be applied without cracks or breakage phenomena is lower than in standard steel joints. Although the preload’s value is admissible, this one is reduced over time due to relaxation phenomena associated with the viscoelastic behaviour of thermoplastic matrix. The results obtained can be improved with the integration of metal inserts in connections’ areas. In this study, a case study of a gear mount replacing the steel core with CFRTP reinforced with inserts is carried out. The results show a reduction above 50% in weight, opening the possibility of lighter structures in the automotive sector.

Download Full-text

Mechanical Properties of Thermoplastic Composites via In Situ Polymerization from Cyclic Oligomers

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.750-752.7 ◽

2013 ◽

Vol 750-752 ◽

pp. 7-10

Author(s):

Kou An Hao ◽

Zhen Qing Wang ◽

Li Min Zhou

Keyword(s):

Mechanical Properties ◽

In Situ Polymerization ◽

High Viscosity ◽

Thermoplastic Composites ◽

Thermoplastic Matrix ◽

Polymerization Catalyst ◽

Short Beam ◽

Beam Shear ◽

Cyclic Oligomers

Fiber impregnation has been the main obstacle for thermoplastic matrix with high viscosity. This problem could be surmounted by adapting low viscous polymeric precursors Woven basalt fabric reinforced poly (butylenes terephthalate) composites were produced via in-situ polymerization at T=210°C. Before polymerization, catalyst was introduced to the reinforcement surface with different concentration. DSC is used to determine the polymerization and crystallization. SEM is used to detect whether the catalyst existed on surface. Both flexural and short-beam shear test are employed to study the corresponding mechanical properties.

Download Full-text

Effect of CNT Grafting on Carbon Fibers on Impact Properties of CFRTP Laminate

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.774.410 ◽

2018 ◽

Vol 774 ◽

pp. 410-415 ◽

Cited By ~ 1

Author(s):

Kazuto Tanaka ◽

Ken Uzumasa ◽

Tsutao Katayama

Keyword(s):

Mechanical Properties ◽

Carbon Fiber ◽

Carbon Fibers ◽

Interfacial Strength ◽

Fiber Surface ◽

Impact Properties ◽

Specific Strength ◽

Out Of Plane ◽

Reinforced Thermoplastics ◽

The Impact

Carbon fiber reinforced thermoplastics (CFRTP) are expected to be used as a structural material for aircraft and automobiles not only for their mechanical properties such as high specific strength and high specific rigidity but also for their high recyclability and short molding time. Generally, in a composite material having a laminated structure, interlaminar delamination is often caused by an out-of-plane impact, so the interlayer property plays an important role in the mechanical properties. It has been reported that the fiber/matrix interfacial strength increases by grafting carbon nanotubes (CNT) on the carbon fiber surface. In this study, CNT grafted carbon fibers were used for reinforcement of CFRTP laminate for the improvement of impact properties of CFRTP laminates. The impact absorbed energy of the CFRTP laminate using CNT grafted carbon fibers as reinforcing fiber was higher than that using untreated CF.

Download Full-text

Thermoactivated Pinning - A Novel Joining Technique for Thermoplastic Composites

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.188.176 ◽

2012 ◽

Vol 188 ◽

pp. 176-181 ◽

Cited By ~ 4

Author(s):

Werner Hufenbach ◽

Robert Kupfer ◽

Andreas Hornig

Keyword(s):

Mechanical Properties ◽

High Volume ◽

Tensile Tests ◽

Thermoplastic Composites ◽

Structural Effects ◽

Short Cycle ◽

Cycle Times ◽

Lap Shear ◽

Thermoplastic Matrix ◽

Manufacturing Techniques

Due to their good mechanical properties and short cycle times during processing, textile-reinforced thermoplastic composites gain increasing relevance for high-volume lightweight applications. Beyond that, by exploiting its specific processing capabilities, this composite material enables a variety of novel manufacturing techniques, e.g. for assembling. In this paper a joining technique is presented, which utilises the meltability of the thermoplastic matrix to establish a material-adapted joining method by introducing slender metallic pins into the composite structure. The processing principle is described and structural effects in the joining zone are analysed by means of microscopy. The load bearing behaviour is characterised by tensile tests on double-lap-shear specimen.

Download Full-text

STUDY ON COOLING RATE-DEPENDENT MECHANICAL PROPERTIES OF THERMOPLASTIC COMPOSITES

10.12783/asc36/35841 ◽

2021 ◽

Author(s):

RYO HIGUCHI ◽

SOTA OSHIMA ◽

SHU MINAKUCHI ◽

TOMOHIRO YOKOZEKI ◽

TAKAHIRA AOKI

Keyword(s):

Mechanical Properties ◽

Cooling Rate ◽

Polyphenylene Sulfide ◽

Constitutive Law ◽

Thermoplastic Composites ◽

Plastic Behavior ◽

Thermoplastic Resin ◽

Rate Dependent ◽

Reinforced Thermoplastics ◽

Fiber Reinforced Thermoplastics

This study investigates the effect of solidification conditions on the crystallization behaviors and mechanical properties of thermoplastic resin and carbon fiber reinforced thermoplastics (CFRTP). In particular, the crystallinity, elastic modulus, plastic behavior, strength, and fracture toughness were investigated in Polyphenylene Sulfide (PPS) and CF/PPS manufactured by different cooling rates. Based on experimental results, the cooling-rate-dependent elasto-plastic constitutive law of resin was developed empirically. Finally, the homogenized simulations of CF/PPS were conducted using the developed empirical model, and predicted results were compared with experiments.

Download Full-text

Assessment of the shear properties of thermoplastic composites using the ±45° tension and the V-notched rail shear methods

Manufacturing Review ◽

10.1051/mfreview/2020007 ◽

2020 ◽

Vol 7 ◽

pp. 10

Author(s):

Antonios G. Stamopoulos ◽

Luca Glauco Di Genova ◽

Antoniomaria Di Ilio

Keyword(s):

Mechanical Performance ◽

Thermoplastic Composites ◽

Testing Methods ◽

Plane Shear ◽

Shear Properties ◽

Thermoplastic Matrix ◽

Glass Fiber Reinforced ◽

Reinforced Thermoplastics ◽

Stress Uniformity

Composite materials consisting of thermoplastic matrix are gaining the interest of both the aeronautical and the automotive industry as they comprise a series of advantages regarding their mechanical performance, their recyclability and their ability to be produced in large quantities. Nevertheless, some notable drawbacks have been noticed related to the fabrication process affecting their in-plane shear properties the characterization of which is complicated. Among the notable number of testing methods proposed throughout the years, several advantages and drawbacks were observed, mostly related to the way the load is applied, the stress uniformity and the applicability of each method to various material architectures. In the present work, the modified V-notched rail shear and the ±45° shear testing methods are applied to short and textile glass fiber reinforced thermoplastics aiming to assess the influence of both the fabrication method and the strands direction. Consecutively, the results obtained from the two different testing methods are compared revealing a relatively good agreement while, in parallel, the stress uniformity and the local failures observed on the specimens are analyzed.

Download Full-text

Kirigami Auxetic Pyramidal Core: Mechanical Properties and Wave Propagation Analysis in Damped Lattice

Journal of Vibration and Acoustics ◽

10.1115/1.4024433 ◽

2013 ◽

Vol 135 (4) ◽

Cited By ~ 29

Author(s):

Fabrizio Scarpa ◽

Morvan Ouisse ◽

Manuel Collet ◽

Kazuya Saito

Keyword(s):

Mechanical Properties ◽

Wave Propagation ◽

Thermoplastic Composites ◽

Long Wavelength ◽

Propagation Analysis ◽

Out Of Plane ◽

Cutting Pattern ◽

Modal Behavior ◽

Propagation Technique ◽

Hysteretic Loss

The work describes the manufacturing, mechanical properties, and wave propagation characteristics of a pyramidal lattice made exhibiting an auxetic (negative Poisson's ratio) behavior. Contrary to similar lattice tessellations produced using metal cores, the pyramidal lattice described in this work is manufactured using a kirigami (origami plus cutting pattern) technique, which can be applied to a large variety of thermoset and thermoplastic composites. Due to the particular geometry created through this manufacturing technique, the kirigami pyramidal lattice shows an inversion between in-plane and out-of-plane mechanical properties compared to classical honeycomb configurations. Long wavelength approximations are used to calculate the slowness curves, showing unusual zero-curvature phononic properties in the transverse plane. A novel 2D wave propagation technique based on Bloch waves for damped structures is also applied to evaluate the dispersion behavior of composite (Kevlar/epoxy) lattices with intrinsic hysteretic loss. The 2D wave propagation analysis shows evanescence directivity at different frequency bandwidths and complex modal behavior due to unusual deformation mechanism of the lattice.

Download Full-text