Short-beam shear strength

Short beam shear tests have been carried out on square cross-section specimens cut from a 32 ply plate. By rotating the beams through 90° both interlaminar and in-plane strength can be measured with identical specimens. The in-plane shear strength was found to be at least 10% higher than the interlaminar strength.

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Microstructure optimizations for improving interlaminar shear strength and self-healing efficiency of spread carbon fiber/epoxy laminates containing microcapsules

Journal of Composite Materials ◽

10.1177/0021998320943941 ◽

2020 ◽

Vol 55 (1) ◽

pp. 27-38

Author(s):

Yasuka Nassho ◽

Kazuaki Sanada

Keyword(s):

Shear Strength ◽

Carbon Fiber ◽

Optical Microscope ◽

Interlaminar Shear Strength ◽

Self Healing ◽

Short Beam ◽

Healing Efficiency ◽

Beam Shear ◽

Interlaminar Shear ◽

Carbon Fiber Epoxy

The purpose of this study is to improve interlaminar shear strength and self-healing efficiency of spread carbon fiber (SCF)/epoxy (EP) laminates containing microcapsules. Microencapsulated healing agents were embedded within the laminates to impart a self-healing functionality. Self-healing was demonstrated on short beam shear specimens, and the healing efficiency was evaluated by strain energies of virgin and healed specimens. The effects of microcapsule concentration and diameter on apparent interlaminar shear strength and healing efficiency were discussed. Moreover, damaged areas after short beam shear tests were examined by an optical microscope to investigate the relation between the microstructure and the healing efficiency of the laminates. The results showed that the stiffness and the apparent interlaminar shear strength of the laminates increased as the microcapsule concentration and diameter decreased. However, the healing efficiency decreased with decreasing the microcapsule concentration and diameter.

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Plasma Nanocoatings Developed to Control the Shear Strength of Polymer Composites

Polymers ◽

10.3390/polym11071188 ◽

2019 ◽

Vol 11 (7) ◽

pp. 1188 ◽

Cited By ~ 1

Author(s):

Zvonek ◽

Sirjovova ◽

Branecky ◽

Plichta ◽

Skacel ◽

...

Keyword(s):

Shear Strength ◽

Polymer Matrix ◽

Polymer Matrix Composites ◽

Glass Fibers ◽

Matrix Composites ◽

Suitable Material ◽

Oxygen Fraction ◽

Short Beam ◽

Beam Shear ◽

Polyester Composite

All reinforcements for polymer-matrix composites must be coated with a suitable material in the form of a thin film to improve compatibility and interfacial adhesion between the reinforcement and the polymer matrix. In this study, plasma nanotechnology was used to synthetize such functional nanocoatings using pure tetravinylsilane (TVS) and its mixtures with oxygen gas (O2) as precursors. The plasma-coated glass fibers (GFs) were unidirectionally embedded in a polyester resin to produce short composite beams that were analyzed by a short-beam-shear test to determine the shear strength characterizing the functionality of the nanocoatings in a GF/polyester composite. The developed plasma nanocoatings allowed controlling the shear strength between 26.2–44.1 MPa depending on deposition conditions, i.e., the radiofrequency (RF) power and the oxygen fraction in the TVS/O2 mixture. This range of shear strength appears to be sufficiently broad to be used in the design of composites.

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Porosity characterization and respective influence on short-beam strength of advanced composite processed by resin transfer molding and compression molding

Polymers and Polymer Composites ◽

10.1177/0967391120968452 ◽

2020 ◽

pp. 096739112096845

Author(s):

Ana Carolina Mendes Quintanilha Silva Santos ◽

Francisco Maciel Monticeli ◽

Heitor Ornaghi ◽

Luis Felipe de Paula Santos ◽

Maria Odila Hilário Cioffi

Keyword(s):

Shear Strength ◽

Mechanical Performance ◽

Volume Fraction ◽

Optimal Parameter ◽

Resin Transfer Molding ◽

Compression Molding ◽

Viscous Force ◽

Transfer Molding ◽

Short Beam ◽

Beam Shear

This work has been developed for a comparative purpose concerning the processing and respective mechanical performance of CFRP composites processed by resin transfer molding (RTM) and compression molding (CM) techniques. Thermal and viscosimetric tests before processing certified the optimal parameter procedure. Both composites were submitted to short-beam shear tests and through microscopy to determine failure mechanisms. CM specimens presented a decrease of 27% in shear strength caused by the presence of macro porosity that induced crack initiation and connection of different delamination plies, causing the speeding up of crack propagation and jump of the interlaminar layer. The low capillary effect and higher viscous force were responsible for macro porosity, inducing heterogeneous impregnation in CM and to the direction reduce in mechanical behavior. On the other hand, more homogeneous impregnation in RTM specimens was responsible for the absence of macro porosity, ensuring higher values of shear strength and lower void volume fraction.

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