Effects of cure cycles on void content and mechanical properties of composite laminates

2006 ◽  
Vol 73 (3) ◽  
pp. 303-309 ◽  
Author(s):  
Ling Liu ◽  
Bo-Ming Zhang ◽  
Dian-Fu Wang ◽  
Zhan-Jun Wu
Keyword(s):  
Mechanical Properties ◽  
Composite Laminates ◽  
Void Content

Cure kinetics and autoclave-pressure dependence on physical and mechanical properties of woven carbon/epoxy 8552S/AS4 composite laminates

2021 ◽  
pp. 096739112110284
Author(s):  
Abd Baghad ◽  
Khalil El Mabrouk ◽  
Sébastien Vaudreuil ◽  
Khalid Nouneh
Keyword(s):  
Mechanical Properties ◽  
Composite Laminates ◽  
Treatment Time ◽  
Physical And Mechanical Properties ◽  
Cure Kinetics ◽  
Void Content ◽  
Scanning Calorimetry ◽  
Microstructure And Mechanical Properties ◽  
The Matrix ◽  
Interlaminar Shear

The final mechanical properties of composite laminates are highly dependent on their curing cycles in the autoclave. During this cycle, the temperature, pressure, vacuum, and treatment time will influence the quality of manufactured parts. The void content is considered the most harmful defects in carbon/epoxy laminates since they weaken the matrix-dominated mechanical properties such as interlaminar shear and compressive strengths. In the present work, differential scanning calorimetry is used to characterize the influence of time/temperature on the behavior of the epoxy resin. Then, a series of [0/90/−45/+45]s laminates composites are autoclave-cured under various applied pressures to evaluate their impact on microstructure and mechanical properties. The interlaminar shear modulus, interlaminar shear strength, laminate compressive modulus, and laminate compressive strength at room and operating engine temperature were measured. The correlation between microstructure and mechanical properties was also studied. The mechanical properties of manufactured carbon/epoxy laminates are found to be dependent on pressure and microstructure. These results are explored to establish an optimal autoclave pressure route that would minimize porosity without counterbalancing mechanical properties.

scholarly journals Degassing and layers variation effect on composite processing by vacuum assisted resin transfer moulding

2021 ◽  
Vol 9 ◽  
Author(s):  
Alpa Tapan Bhatt ◽  
◽  
Piyush P Gohil ◽  
Vijaykumar Chaudhary ◽  
◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Composite Laminates ◽  
Critical Issue ◽  
Thickness Variation ◽  
Void Content ◽  
Vacuum Degassing ◽  
Reinforced Composite ◽  
Before And After ◽  
Transfer Moulding ◽  
Vartm Process

Vacuum assisted resin transfer molding (VARTM) is a fiber reinforced composite (FRC) making process in which resin is impregnated to fabric by application of vacuum. This process is also known as vacuum infusion process. The critical issue in VARTM process is void generation. Voids form due to variety of reasons, most of which can be avoided. Vacuum degassing is one of the solutions which will reduce air entrapped inside resin during impregnation. In this work six laminates from jute and polyester resin were prepared, three with degassing and three without degassing with variation in number of jute layers 5, 10 and 15 respectively. Microscopic examination and mechanical properties have been observed before and after degassing. It was observed that degassing improves mechanical properties of composite laminates and reduce void content. It was observed that the thickness variation in laminate increased as number of layer increased.

VARTM Process Improvement for Repeatable and Improved Mechanical Properties of Composite Laminates

2009 ◽  
Author(s):  
Sanjay Sharma ◽  
Dennis A. Siginer
Keyword(s):  
Mechanical Properties ◽  
Process Parameters ◽  
Composite Laminates ◽  
Volume Fraction ◽  
Void Content ◽  
Molding Process ◽  
Fiber Volume ◽  
The Impact ◽  
Vartm Process

Quality of laminates produced by Seeman Composite Resin Infusion Molding Process (SCRIMP) is studied by comparing their Fiber Volume fraction and void content. SCRIMP is a variant of Vacuum Assisted Resin Transfer Molding (VARTM). Manufacturing process parameters are then identified and varied to study the impact on mechanical properties of laminated composites. Modification to SCRIMP is carried out by infusing the resin under additional pressure. Optimal process parameters for this modified SCRIMP process are suggested to yield laminates that are repeatable and consistent in quality. Void content is reduced in the composite laminates by altering the vacuum pressure level. Thickness gradient commonly found in SCRIMP processed laminates is eliminated by allowing longer de-bulking time. Final laminate quality is measured using ASTM standardized mechanical testing.

Influence of the Impregnation Velocity on Impregnation Quality and Mechanical Properties of Vacuum Assisted Resin Transfer Moulding (VARTM) Materials

2015 ◽  
Vol 825-826 ◽  
pp. 36-43
Author(s):  
Vasiliki Maria Archodoulaki ◽  
Massimiliano Merola ◽  
Dimitrios Kastanis ◽  
Thomas Koch ◽  
Pierpaolo Carlone
Keyword(s):  
Mechanical Properties ◽  
Composite Laminates ◽  
Injection Pressure ◽  
Fiber Material ◽  
Processing Parameters ◽  
Optical Microscope ◽  
Void Content ◽  
Strong Impact ◽  
Apparent Difference ◽  
The Difference

Vacuum Assisted Resin Transfer Molding (VARTM) fabricated FRP laminates generally show significantly small void contents. The apparent difference in void content is generally attributed to the difference in the resin infusion driving force, i.e., vacuum versus injection pressure. In the present study, we contrast the influence of processing parameters on the impregnation quality of FRP laminates. Application of different vacuum pressures (500, 800 and ~103 mbar) during VARTM results in different impregnation velocity due to different compaction levels produced. Composite laminates were realized using epoxy resin reinforced with carbon (CF) or glass continuous (GF) fibers. Two different textile architectures, namely unidirectional non-crimp fabrics (UD) and woven-mat (0/90), were used and various processing conditions were employed. Optical microscope observations revealed an unexpected trend relatively to the intra and inter bundle voids concentration with respect to the impregnation velocity, especially using UD-CF and UD-GF reinforcements and low impregnation rate. Tensile and three point bending tests highlighted the strong impact of fiber material and architecture on mechanical properties, whereas the presence of voids played a slight influence on the fiber dominated characteristics analyzed.

Effect of ethanol on the mold filling-time and mechanical properties of woven glass fiber reinforced epoxy filled with TiO2 nanoparticles

2020 ◽  
pp. 152808372097134
Author(s):  
Sherif M Youssef ◽  
M Megahed ◽  
Soliman S Ali-Eldin ◽  
MA Agwa
Keyword(s):  
Mechanical Properties ◽  
Composite Laminates ◽  
Cost Effective ◽  
Mold Filling ◽  
High Viscosity ◽  
Ansys Fluent ◽  
Glass Fiber Reinforced ◽  
Filling Time ◽  
Ethanol Addition ◽  
Woven Glass Fiber

Vacuum resin infusion (VRI) is a promising technique for manufacturing complicated structural laminates. This high viscosity of nanofilled resin increases the filling time and leads to an incomplete mold filling. The mold filling time can be reduced either by making the fiber dimensions smaller than the mold (gaps around the fibers) or by adding ethanol to nanofilled epoxy. However, ethanol addition influences the mechanical properties of composite laminates. In this study, different amounts of ethanol (0.5 wt. % and 1 wt. %) were used as a diluent to both neat epoxy and epoxy filled with (0.25 wt. %) of titanium dioxide (TiO2) nanoparticles. From results, it was found that ethanol addition saves the time for neat and nanofilled epoxy by 47.1% and 24.1%, respectively. It was found that adding 0.5 wt. % of ethanol to 0.25wt. % of TiO2 nanoparticles (GT0.25E0.5) enhances the tensile and flexural strength by 30.8% and 55.9%, respectively compared with neat specimens. Furthermore, the tensile and flexural moduli increased by 62% and 72.3%, respectively. Furthermore, the mold filling time was investigated experimentally and validated numerically using ANSYS FLUENT software. The mold filling time prediction using ANSYS FLUENT can be used to avoid resin gelation before the incomplete mold filling and thus can be considered a cost-effective methodology. The results showed that the gaps around the fibers reduce the time by 178% without affecting the mechanical properties.

Effect of fibre content on the mechanical properties of hemp fibre woven fabrics/polypropylene composite laminates

2021 ◽  
pp. 096739112110239
Author(s):  
Sheedev Antony ◽  
Abel Cherouat ◽  
Guillaume Montay
Keyword(s):  
Mechanical Properties ◽  
Polymer Matrix ◽  
Composite Laminates ◽  
Volume Fraction ◽  
Fibre Volume Fraction ◽  
Fibre Volume ◽  
Woven Fabrics ◽  
Fibre Content ◽  
Viscoelastic Behaviour ◽  
Hemp Fibre

Nowadays natural fibre composites have gained great significance as reinforcements in polymer matrix composites. Composite material based on a polymer matrix reinforced with natural fibres is extensively used in industry due to their biodegradability, recyclability, low density and high specific properties. A study has been carried out here to investigate the fibre volume fraction effect of hemp fibre woven fabrics/PolyPropylene (PP) composite laminates on the tensile properties and impact hammer impact test. Initially, composite sheets were fabricated by the thermal-compression process with desired number of fabric layers to obtain composite laminates with different fibre volume fraction. Uniaxial, shear and biaxial tensile tests were performed and mechanical properties were calculated. Impact hammer test was also carried out to estimate the frequency and damping parameters of stratified composite plates. Scanning Electron Microscope (SEM) analysis was performed to observe the matrix and fibre constituent defects. Hemp fabrics/PP composite laminates exhibits viscoelastic behaviour and as the fibre volume fraction increases, the viscoelastic behaviour decreases to elastic behaviour. Due to this, the tensile strength increases as the fibre content increases. On the other hand, the natural frequency increases and damping ratio decrease as the fibre volume fraction increases.

Effect of Ceramic Fillers on Mechanical Properties of Bamboo Fiber Reinforced Epoxy Composites: A Comparative Study

2010 ◽  
Vol 123-125 ◽  
pp. 1031-1034 ◽  
Author(s):  
Sandhyarani Biswas ◽  
Alok Satapathy ◽  
Amar Patnaik
Keyword(s):  
Mechanical Properties ◽  
Silicon Carbide ◽  
Red Mud ◽  
Synergistic Effects ◽  
Bamboo Fiber ◽  
Industrial Wastes ◽  
Epoxy Composites ◽  
Void Content ◽  
Filler Materials ◽  
Fiber Reinforced

In order to obtain the favoured material properties for a particular application, it is important to know how the material performance changes with the filler content under given loading conditions. In this study, a series of bamboo fiber reinforced epoxy composites are fabricated using conventional filler (aluminium oxide (Al2O3) and silicon carbide (SiC) and industrial wastes (red mud and copper slag) particles as filler materials. By incorporating the chosen particulate fillers into the bamboo-fiber reinforced epoxy, synergistic effects, as expected are achieved in the form of modified mechanical properties. Inclusion of fiber in neat epoxy improved the load bearing capacity (tensile strength) and the ability to withstand bending (flexural strength) of the composites. But with the incorporation of particulate fillers, the tensile strengths of the composites are found to be decreasing in most of the cases. Among the particulate filled bamboo-epoxy composites, least value of void content are recorded for composites with silicon carbide filling and for the composites with glass fiber reinforcement minimum void fraction is noted for red mud filling. The effects of these four different ceramics on the mechanical properties of bamboo- epoxy composites are investigated and the conclusions drawn from the above investigation are discussed.

scholarly journals EFFECTS OF POROSITY ON ULTRASONIC CHARACTERISTIC PARAMETERS AND MECHANICAL PROPERTIES OF GLASS FIBER REINFORCED COMPOSITES

2012 ◽  
Vol 06 ◽  
pp. 646-651 ◽  
Author(s):  
Wen Ma ◽  
Fushun Liu
Keyword(s):  
Mechanical Properties ◽  
Ultrasonic Attenuation ◽  
Ultrasonic Inspection ◽  
Fiber Reinforced Composites ◽  
Metallographic Analysis ◽  
Void Content ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Characteristic Parameters ◽  
Distribution Shape

Voids are inevitable in the fabrication of fiber reinforced composites and have a detrimental impact on mechanical properties of composites. Different void contents were acquired by applying different vacuum bag pressures. Ultrasonic inspection and ablation density method were adopted to measure the ultrasonic characteristic parameters and average porosity, the characterization of voids' distribution, shape and size were carried out through metallographic analysis. Effects of void content on the tensile, flexural and interlaminar shear properties and the ultrasonic characteristic parameters were discussed. The results showed that, as vacuum bag pressure went from -50kPa to -98kPa, the voids content decreased from 4.36 to 0.34, the ultrasonic attenuation coefficient decreased, but the mechanical strengths all increased.

Mechanical Properties in Notched AS-4/PEEK APC-2 Composite Laminates at Elevated Temperature

2005 ◽  
Vol 40 (11) ◽  
pp. 955-969 ◽  
Author(s):  
Ming-Hwa R. Jen ◽  
Yu-Chung Tseng ◽  
Shi-Chao Chang ◽  
Ming Chen
Keyword(s):  
Mechanical Properties ◽  
Elevated Temperature ◽  
Composite Laminates
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