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

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.

Modified Short Beam Shear Test for Measuring Interlaminar Shear Strength of Composites

AIAA Journal ◽  
2002 ◽  
Vol 40 (11) ◽  
pp. 2368-2370
Author(s):  
Kunigal Shivakumar ◽  
Felix Abali ◽  
Adrian Pora
Keyword(s):  
Shear Strength ◽  
Shear Test ◽  
Interlaminar Shear Strength ◽  
Short Beam ◽  
Beam Shear ◽  
Interlaminar Shear

scholarly journals A Comparison between Interlaminar and In-plane Shear Strength of Unidirectional Glass Fibre-epoxy

1994 ◽  
Vol 3 (2) ◽  
pp. 096369359400300 ◽  
Author(s):  
Michael R. Wisnom ◽  
M. I. Jones
Keyword(s):  
Shear Strength ◽  
Cross Section ◽  
Glass Fibre ◽  
Shear Tests ◽  
Plane Shear ◽  
Short Beam ◽  
Unidirectional Glass ◽  
Beam Shear

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.

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

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.

scholarly journals Impact and shear properties of carbon fabric/ poly-dicyclopentadiene composites manufactured by vacuum‐assisted resin transfer molding

e-Polymers ◽  
2019 ◽  
Vol 19 (1) ◽  
pp. 437-443 ◽  
Author(s):  
Hyeong Min Yoo ◽  
Moo Sun Kim ◽  
Bum Soo Kim ◽  
Dong Jun Kwon ◽  
Sung Woong Choi
Keyword(s):  
Impact Strength ◽  
Volume Fraction ◽  
Epoxy Composite ◽  
Resin Transfer Molding ◽  
Maximum Shear Stress ◽  
Weight Percent ◽  
Fiber Volume ◽  
Shear Properties ◽  
Transfer Molding ◽  
The Impact

AbstractDicyclopentadiene (DCPD) resin has gained popularity owing to its fast curing time and ease of processing with a low viscosity in the monomer state. In the present study, the impact and shear properties of a carbon fiber (CF)/p-DCPD composite were investigated. The CF/p-DCPD composite was manufactured by vacuum-assisted resin transfer molding with CF as the reinforcement and p-DCPD as the resin with a maximum fiber volume fraction of 55 weight percent. Impact and shear properties of the CF/p-DCPD composite were evaluated and compared with those of a CF/Epoxy composite. The maximum shear stress and modulus of the CF/p-DCPD composite were lower than that of the CF/Epoxy composite. However, the CF/p-DCPD composite had higher toughness than that of the CF/Epoxy composite; this indicates that it is tougher and exhibits a more ductile load-displacement response with a lower modulus and larger failure deformation. The impact strength of the CF/p-DCPD composite was about three time that of the CF/Epoxy composite. The higher impact strength of the CF/p-DCPD composite is attributed to the resin characteristics: epoxy resin has a more brittle behavior, and hence, higher energy is required for crack propagation due to fracture.

scholarly journals Plasma Nanocoatings Developed to Control the Shear Strength of Polymer Composites

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1188 ◽  
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.

scholarly journals The effect of processing on the microstructure of hoop-wound composite cylinders

2020 ◽  
Vol 54 (26) ◽  
pp. 3981-3997 ◽  
Author(s):  
Kaspar Lasn ◽  
Mats Mulelid
Keyword(s):  
Mechanical Performance ◽  
Pressure Vessels ◽  
Void Content ◽  
Cylinder Wall ◽  
Process Innovations ◽  
Short Beam ◽  
Beam Shear ◽  
Composite Microstructure ◽  
The Difference ◽  
Composite Cylinders

Fibre-reinforced polymer composites are increasingly used to make pipes and pressure vessels. The relationship between wet-winding manufacturing, composite microstructure, and the mechanical performance is complex due to many process parameters and material properties involved. Efficient manufacturing aspirations however drive process innovations that include new, radically different tow impregnation methods. In this work, the process–property–performance relationship is experimentally construed for hoop-wound carbon fibre/epoxy composite cylinders. The difference between cylinders produced by a new tow impregnation system and cylinders from the reference impregnation system was investigated. Winding speed and cylinder wall thickness were considered as two additional variables. The results indicate that, within current scope, composite microstructure is relatively insensitive to the winding speed and to final cylinder thickness. Meanwhile, un-optimized changes for tow impregnation affect the void content, the size distribution of voids and the interlaminar failure mode in short beam shear.

Development of novel high Tg polyimide-based composites. Part II: Mechanical characterisation

2017 ◽  
Vol 52 (2) ◽  
pp. 261-274 ◽  
Author(s):  
Spyros Tsampas ◽  
Patrik Fernberg ◽  
Roberts Joffe
Keyword(s):  
Elevated Temperature ◽  
Composite System ◽  
Mechanical Performance ◽  
Mechanical Tests ◽  
Basic Material ◽  
Mechanical Characterisation ◽  
Short Beam ◽  
Fibre Treatment ◽  
Beam Shear ◽  
Fibre Matrix

In this study, the mechanical performance assessment of a newly developed carbon fibre-reinforced polyimide composite system T650/NEXIMID® MHT-R is presented. This system was subjected to a series of mechanical tests at ambient and elevated temperature (320℃) to determine basic material properties. Moreover, an additional test was conducted, using a T650/NEXIMID® MHT-R laminate in which the fibre sizing was thermally removed prior to laminate manufacturing, to investigate the effect of fibre treatment on mechanical performance. The experimental results indicated that the T650/NEXIMID® MHT-R composites along with exceptionally high Tg (360–420℃) exhibited competitive mechanical properties to other commercially available polyimide and epoxy-based systems. At elevated temperature, the fibre-dominated properties were not affected whilst the properties defined by matrix and fibre/matrix interface were degraded by approximately 20–30%. Finally, the fibre sizing removal did not affect the tensile and compressive strength, however, the shear strength obtained from short-beam shear test was deteriorated by approximately 15%.

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