Composite materials have been well documented in engineering technology. They have replaced traditional materials (metals and alloys) in engineering technologies for over two decades due to their performance and characteristics. Composite structure generally consists of reinforcement and matrix. Car...
Composite materials have been well documented in engineering technology. They have replaced traditional materials (metals and alloys) in engineering technologies for over two decades due to their performance and characteristics. Composite structure generally consists of reinforcement and matrix. Carbon fiber is a superior in organic fiber utilized as a composite reinforcement. It is widely applied especially on advanced technological purposes due to its inherent properties but it has the drawback of being characteristically brittle and expensive. Hybridization is a good approach to make good the weakness of a carbon fiber wherein it is usually combined with glass fibers. But the use of glass fibers is not worthy due to its toxicity although it improves the characteristics and production costs of the composite. The present study is focused on interply hybrid composite between the carbon fabric and basalt fiber as a function of basalt fabric content and alternate stacking sequence. Tensile, flexural and Mode I fracture toughness tests were conducted to investigate the mechanical characteristics of an interply hybrid composite. The purpose of this study is to describe the mechanical characteristics of a carbon-basalt/epoxy interply hybrid composite and to provide additional information about basalt fabric-based hybrid composites. Specifically, it is to measure and investigate the mechanical characteristics of interply hybrid composites based on the basalt fabrics content and alternate stacking sequence on quasi-statics tests. Tensile stress–strain curves were measured via standardized tests of ASTM D 638 to provide the elastic modulus, yield stress, ultimate strength, strain to failures, as well as a preliminary assessment of toughness. Flexural test was conducted with standardized tests of ASTM D 790 to find out the bending stiffness and strength. The fracture toughness, KIC, is calculated using the compliance method. The fracture toughness was determined as the function of specimen geometry, loading and crack extension of interply hybrid composites in accordance with the standardized ASTM D 5045. The effect of hybridization was analyzed using the Rule of Mixture. Each sample of the interply hybrid composite used in this study was fabricated using the vacuum assisted resin transfer molding (VARTM) process. Ten plies of carbon and basalt fabrics were prepared to be used only for tensile and flexural tests and then eighty plies more for Mode I fracture toughness test. Carbon fabrics C120-3K and Basalt fabrics EcoB4-F210 were employed respectively and furthermore, Epoxy resin HTC-667C with modified aliphatic hardener for matrix was used. The structure of the interply hybrid composite is based on its basalt fabric content which varies from 10% to 50% of the carbon fiber reinforced polymer (CFRP) (i.e., C5B¬1C4, C4B2C4, C4B3C3, C3B4C3 and C3B5C2). Furthermore, the structure design was based on the alternate stacking sequence (C3B4C3, B2C6B2 and C2B2C2B2C2). The compact tension (CT) specimen was designed according to basalt content of 10% to 40% of the carbon fabrics reinforced polymer and was based on alternate stacking sequence. All of the samples were cut using a water-jet machine. Five specimens were prepared and examined for each of the test conditions which are assumed anisotropic homogeneous in the two dimensional approach. This study showed that the tensile stress-strain curves presented linearity with increasing basalt fabric contents into the CFRP. as results, we can see that the initial slope of the stress-strain curves demonstrated a proportional decrease. However, the fracture strain showed an increasing trend. The tensile strength for interply hybrid composite as against the CFRP showed a decrease of 9.05%, 14.12%, 23.12%, 28.17% and 36.85% for each increasing basalt fabric content. The Young’s modulus is also decreased by 10.17%, 18.18%, 27.45%, 32.29% and 62.5% for each addition of basalt fabrics, respectively. Moreover, alternate stacking sequence showed that B2C6B2 (D2) has the highest tensile strength and Young's modulus of about 571 MPa and 49.5 GPa (6.53% and 5.32%) compared with C3B4C3 (C4) and C2B2C2B2C2 (E), respectively. This result proved that stacking sequence with basalt fabrics on the exterior region has a major effect on the tensile strength and Young’s modulus but only a slight influence on the tensile strain. The typical load-displacement curve for interply hybrid composite as a function of basalt content showed linear characteristics based on the result of the flexural tests but the stiffness and strength values are less than those of CFRP. In this case, the flexural strength and flexural modulus of interply hybrid composite decreased linearly with increasing basalt fabrics content (10% until 50%) to a maximum of about 18.66% and 17.5% as against the CFRP, respectively. In the flexural experiment as a function of arrangement of sequences between carbon fabric and basalt fabric (4 ply basalt fabrics and 6 ply carbon fabrics), the initial slopes of interply hybrid composites exhibited linear characteristics. Consequently, the flexural strength and flexural modulus of elasticity have high values when the position of carbon fabrics at the compressive side compared with hybrid composite with basalt fabric at the compressive side. Specifically, the interply hybrid composite with arrangement sequence of C2B2C2B2C2 has a high modulus of about 46.408 GPa. The present results suggest that the incorporation of basalt fabrics into CFRP could improve the mechanical characteristic depending on the stacking sequences. Mode I fracture toughness test showed that the fracture toughness KIC of interply hybrid composites decreases with increasing basalt fabric content in the CFRP. The interply hybrid composite (C36B8C36) decreased by 3.15% as against the CFRP. Additionally, increasing basalt fabric content (10% until 40%) of the CFRP decreased the fracture toughness by 5.46%, 8.87% and 7.56% for each addition of basalt fabrics, respectively. The interply hybrid composite as a function of alternate stacking sequence between the carbon and basalt fabrics have shown an increase in fracture toughness value. Results showed that the interply hybrid composite (C16B16C16B16C16) has the highest fracture toughness value of about 36.083 (MPa√m) compared with that of C24B32C24 and B16C64B16 proving that the arrangement of fabric between carbon and basalt fabrics significantly influences the fracture toughness of composite materials. Fracture surface analysis through SEM showed that pull-out, de-bonding, fiber unraveled and delamination were common occurring features on interply hybrid composite of carbon fabric and basalt fabric epoxy matrix. In addition, shear hackles are formed due to the matrix (epoxy) cracks on the plane of maximum tension and perpendicular to the direction of delamination. Carbon fabrics generally fail in brittle manner while basalt fabrics fail in an unraveled manner. To sum up the hybridization effect based on the rule of mixtures, it can be described that increasing basalt fiber content and the use of alternate stacking sequence influenced the mechanical characteristics of composite materials. Hybridization also gives a good balance between the desired mechanical properties and production costs.
Composite materials have been well documented in engineering technology. They have replaced traditional materials (metals and alloys) in engineering technologies for over two decades due to their performance and characteristics. Composite structure generally consists of reinforcement and matrix. Carbon fiber is a superior in organic fiber utilized as a composite reinforcement. It is widely applied especially on advanced technological purposes due to its inherent properties but it has the drawback of being characteristically brittle and expensive. Hybridization is a good approach to make good the weakness of a carbon fiber wherein it is usually combined with glass fibers. But the use of glass fibers is not worthy due to its toxicity although it improves the characteristics and production costs of the composite. The present study is focused on interply hybrid composite between the carbon fabric and basalt fiber as a function of basalt fabric content and alternate stacking sequence. Tensile, flexural and Mode I fracture toughness tests were conducted to investigate the mechanical characteristics of an interply hybrid composite. The purpose of this study is to describe the mechanical characteristics of a carbon-basalt/epoxy interply hybrid composite and to provide additional information about basalt fabric-based hybrid composites. Specifically, it is to measure and investigate the mechanical characteristics of interply hybrid composites based on the basalt fabrics content and alternate stacking sequence on quasi-statics tests. Tensile stress–strain curves were measured via standardized tests of ASTM D 638 to provide the elastic modulus, yield stress, ultimate strength, strain to failures, as well as a preliminary assessment of toughness. Flexural test was conducted with standardized tests of ASTM D 790 to find out the bending stiffness and strength. The fracture toughness, KIC, is calculated using the compliance method. The fracture toughness was determined as the function of specimen geometry, loading and crack extension of interply hybrid composites in accordance with the standardized ASTM D 5045. The effect of hybridization was analyzed using the Rule of Mixture. Each sample of the interply hybrid composite used in this study was fabricated using the vacuum assisted resin transfer molding (VARTM) process. Ten plies of carbon and basalt fabrics were prepared to be used only for tensile and flexural tests and then eighty plies more for Mode I fracture toughness test. Carbon fabrics C120-3K and Basalt fabrics EcoB4-F210 were employed respectively and furthermore, Epoxy resin HTC-667C with modified aliphatic hardener for matrix was used. The structure of the interply hybrid composite is based on its basalt fabric content which varies from 10% to 50% of the carbon fiber reinforced polymer (CFRP) (i.e., C5B¬1C4, C4B2C4, C4B3C3, C3B4C3 and C3B5C2). Furthermore, the structure design was based on the alternate stacking sequence (C3B4C3, B2C6B2 and C2B2C2B2C2). The compact tension (CT) specimen was designed according to basalt content of 10% to 40% of the carbon fabrics reinforced polymer and was based on alternate stacking sequence. All of the samples were cut using a water-jet machine. Five specimens were prepared and examined for each of the test conditions which are assumed anisotropic homogeneous in the two dimensional approach. This study showed that the tensile stress-strain curves presented linearity with increasing basalt fabric contents into the CFRP. as results, we can see that the initial slope of the stress-strain curves demonstrated a proportional decrease. However, the fracture strain showed an increasing trend. The tensile strength for interply hybrid composite as against the CFRP showed a decrease of 9.05%, 14.12%, 23.12%, 28.17% and 36.85% for each increasing basalt fabric content. The Young’s modulus is also decreased by 10.17%, 18.18%, 27.45%, 32.29% and 62.5% for each addition of basalt fabrics, respectively. Moreover, alternate stacking sequence showed that B2C6B2 (D2) has the highest tensile strength and Young's modulus of about 571 MPa and 49.5 GPa (6.53% and 5.32%) compared with C3B4C3 (C4) and C2B2C2B2C2 (E), respectively. This result proved that stacking sequence with basalt fabrics on the exterior region has a major effect on the tensile strength and Young’s modulus but only a slight influence on the tensile strain. The typical load-displacement curve for interply hybrid composite as a function of basalt content showed linear characteristics based on the result of the flexural tests but the stiffness and strength values are less than those of CFRP. In this case, the flexural strength and flexural modulus of interply hybrid composite decreased linearly with increasing basalt fabrics content (10% until 50%) to a maximum of about 18.66% and 17.5% as against the CFRP, respectively. In the flexural experiment as a function of arrangement of sequences between carbon fabric and basalt fabric (4 ply basalt fabrics and 6 ply carbon fabrics), the initial slopes of interply hybrid composites exhibited linear characteristics. Consequently, the flexural strength and flexural modulus of elasticity have high values when the position of carbon fabrics at the compressive side compared with hybrid composite with basalt fabric at the compressive side. Specifically, the interply hybrid composite with arrangement sequence of C2B2C2B2C2 has a high modulus of about 46.408 GPa. The present results suggest that the incorporation of basalt fabrics into CFRP could improve the mechanical characteristic depending on the stacking sequences. Mode I fracture toughness test showed that the fracture toughness KIC of interply hybrid composites decreases with increasing basalt fabric content in the CFRP. The interply hybrid composite (C36B8C36) decreased by 3.15% as against the CFRP. Additionally, increasing basalt fabric content (10% until 40%) of the CFRP decreased the fracture toughness by 5.46%, 8.87% and 7.56% for each addition of basalt fabrics, respectively. The interply hybrid composite as a function of alternate stacking sequence between the carbon and basalt fabrics have shown an increase in fracture toughness value. Results showed that the interply hybrid composite (C16B16C16B16C16) has the highest fracture toughness value of about 36.083 (MPa√m) compared with that of C24B32C24 and B16C64B16 proving that the arrangement of fabric between carbon and basalt fabrics significantly influences the fracture toughness of composite materials. Fracture surface analysis through SEM showed that pull-out, de-bonding, fiber unraveled and delamination were common occurring features on interply hybrid composite of carbon fabric and basalt fabric epoxy matrix. In addition, shear hackles are formed due to the matrix (epoxy) cracks on the plane of maximum tension and perpendicular to the direction of delamination. Carbon fabrics generally fail in brittle manner while basalt fabrics fail in an unraveled manner. To sum up the hybridization effect based on the rule of mixtures, it can be described that increasing basalt fiber content and the use of alternate stacking sequence influenced the mechanical characteristics of composite materials. Hybridization also gives a good balance between the desired mechanical properties and production costs.
주제어
#Mechanical properties Interply hybrid composite Vacuum assisted resin transfer molding (VARTM) process Carbon fabrics Basalt fabrics fracture mechanics Hybridization tensile test flexural test Mode I fracture toughness test
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