ABSTRACT In this study, the effects of adhesive modification, surface treatment of laminates, and their combined effects on the bonding properties of adhesive joints were studied using tensile shear tests, SEM micro-morphology characterisation, EDS energy spectra, analysis of the load-displacement curve, failure mode, and element content on the bonding surface. The test group corresponding to surface treatment of the laminate exhibited the best tensile shear performance. Surface treatment by 20% NaOH increased the tensile shear strength and failure displacement by 30.41% and 106.72%, respectively, compared to that obtained with only surface polishing using 320# sandpaper. In the adhesive modification test group, the tensile shear strength of the joint was the largest with an adhesive modification by 3 wt.% short glass fibres, while the tensile shear strength and failure displacement increased by 7.96% (18.63 MPa) and 10.2%, respectively, compared with those without adhesive modification. To further improve the wettability and interfacial bonding strength between the glass fibre and adhesive, a 3 wt.% short glass fibre was pretreated with KH-550 silane coupling agent. The tensile shear strength of the joint improved to 19.06 MPa, and the maximum failure displacement was 1.59 mm, which were 2.31% and 2.58% higher than those without KH-550 silane coupling agent pretreatment on the glass fibre, respectively. Furthermore, adhesive modification by KH-550 treated 3 wt.% short glass fibre was underwent combining with laminate surface treatment with 20% NaOH. The bonding strength was higher than that obtained using 3 wt.% GF adhesive modification pretreated with KH-550, while lower by 10.49% compared with that corresponding to the surface treatment of the laminate by 20% NaOH. This was primarily attributed to the pores produced by the hydrolysis reaction between NaOH and the KH-550 silane coupling agent, which weakened the load-bearing capacity of the joint.
{"title":"Effect of adhesive modification and surface treatment of laminates on the single lap bonding joint properties of carbon fibre composites","authors":"S. Lou, Baojia Cheng, Guodong Ren, Yiming Li, Xuefeng Bai, Pengcheng Chen","doi":"10.1080/00218464.2022.2163893","DOIUrl":"https://doi.org/10.1080/00218464.2022.2163893","url":null,"abstract":"ABSTRACT In this study, the effects of adhesive modification, surface treatment of laminates, and their combined effects on the bonding properties of adhesive joints were studied using tensile shear tests, SEM micro-morphology characterisation, EDS energy spectra, analysis of the load-displacement curve, failure mode, and element content on the bonding surface. The test group corresponding to surface treatment of the laminate exhibited the best tensile shear performance. Surface treatment by 20% NaOH increased the tensile shear strength and failure displacement by 30.41% and 106.72%, respectively, compared to that obtained with only surface polishing using 320# sandpaper. In the adhesive modification test group, the tensile shear strength of the joint was the largest with an adhesive modification by 3 wt.% short glass fibres, while the tensile shear strength and failure displacement increased by 7.96% (18.63 MPa) and 10.2%, respectively, compared with those without adhesive modification. To further improve the wettability and interfacial bonding strength between the glass fibre and adhesive, a 3 wt.% short glass fibre was pretreated with KH-550 silane coupling agent. The tensile shear strength of the joint improved to 19.06 MPa, and the maximum failure displacement was 1.59 mm, which were 2.31% and 2.58% higher than those without KH-550 silane coupling agent pretreatment on the glass fibre, respectively. Furthermore, adhesive modification by KH-550 treated 3 wt.% short glass fibre was underwent combining with laminate surface treatment with 20% NaOH. The bonding strength was higher than that obtained using 3 wt.% GF adhesive modification pretreated with KH-550, while lower by 10.49% compared with that corresponding to the surface treatment of the laminate by 20% NaOH. This was primarily attributed to the pores produced by the hydrolysis reaction between NaOH and the KH-550 silane coupling agent, which weakened the load-bearing capacity of the joint.","PeriodicalId":14778,"journal":{"name":"Journal of Adhesion","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2023-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45272749","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.1080/00218464.2022.2161897
S. Fevery, K. Van Massenhove, S. Debruyne, D. Vandepitte, H. Hallez
ABSTRACT There are currently little widely used structural health monitoring (SHM) techniques for structural adhesive joints. In this study, integrated fibre Bragg grating (FBG) sensors are used to examine the structural integrity and reliability of functional adhesive joints. There is an even greater demand for structural monitoring during operation or quality control of adhesive joints during production as more industries embrace high performance structural adhesives in fail-safe designs. Smartroof® photovoltaic (PV) roof tiles are used in this study to validate a real-time health monitoring of the adhesive connection between the PV glass plate and the polymer frame. A structural epoxy and a modified siloxane (MS) polymer are assessed. To assure measurement accuracy and to provide a better understanding of the strain sensing mechanism, the data is qualitatively compared with a finite element model. It is demonstrated that using embedded FBG sensors is accurate and adequate for in situ real-time structural health monitoring. Nevertheless, it remains difficult to ensure and manage the fibre’s position in the adhesive layer.
{"title":"Structural health monitoring of Cerasol® roof tiles with embedded FBG sensors","authors":"S. Fevery, K. Van Massenhove, S. Debruyne, D. Vandepitte, H. Hallez","doi":"10.1080/00218464.2022.2161897","DOIUrl":"https://doi.org/10.1080/00218464.2022.2161897","url":null,"abstract":"ABSTRACT There are currently little widely used structural health monitoring (SHM) techniques for structural adhesive joints. In this study, integrated fibre Bragg grating (FBG) sensors are used to examine the structural integrity and reliability of functional adhesive joints. There is an even greater demand for structural monitoring during operation or quality control of adhesive joints during production as more industries embrace high performance structural adhesives in fail-safe designs. Smartroof® photovoltaic (PV) roof tiles are used in this study to validate a real-time health monitoring of the adhesive connection between the PV glass plate and the polymer frame. A structural epoxy and a modified siloxane (MS) polymer are assessed. To assure measurement accuracy and to provide a better understanding of the strain sensing mechanism, the data is qualitatively compared with a finite element model. It is demonstrated that using embedded FBG sensors is accurate and adequate for in situ real-time structural health monitoring. Nevertheless, it remains difficult to ensure and manage the fibre’s position in the adhesive layer.","PeriodicalId":14778,"journal":{"name":"Journal of Adhesion","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"59097293","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.1080/00218464.2022.2163892
J. Xavier, Raja Beryl J, R. N
ABSTRACT Diethoxy(3-glycidyloxypropyl) methylsilane (GPMS), a surface modification agent, is used to give halloysite nanoparticles a hydrophobic behaviour and improve their ability to disperse in epoxy polymers (EP). Surface roughness and hydrophobicity (WCA: 144°) are both quite high in EP-GPMS/Clay coatings. The corrosion behavior of coated steel surfaces was investigated using electrochemical methods. The EP-GPMS/clay nanocomposite coating was shown to have about 63 times higher coating resistance than the EP coating. The EP-GPMS/Clay displayed better coating resistance (6687.71 kΩ.cm2) and a lower corrosion current density (4.25 μA/cm2) than plain epoxy (1.01 kΩ.cm2; 287.21 μA/cm2) even after prolonged exposure to the electrolyte, according to electrochemical studies. Compared to the pure EP (0.0599 mm/year), the EP-GPMS/clay coated sample had the lowest corrosion rate (0.0017 mm/year). According to SECM data, at 15 d of immersion, the Fe dissipation at the surface of the EP-GPMS/Clay coating (2.6 nA) is much smaller than the plain EP (14.7 nA). Additionally, the EP-GPMS/Clay showed enhanced adhesive properties. The EP with silanized clay offers an outstanding oxygen and water repellent, hydrophobic, and barrier properties. Due to the environmental safety of clay/silane, this kind of coating might be employed as a workable coating substance for industrial applications.
{"title":"A study on the influence of silanized clay on the barrier, hydrophobic and mechanical properties of epoxy coated steel in natural seawater","authors":"J. Xavier, Raja Beryl J, R. N","doi":"10.1080/00218464.2022.2163892","DOIUrl":"https://doi.org/10.1080/00218464.2022.2163892","url":null,"abstract":"ABSTRACT Diethoxy(3-glycidyloxypropyl) methylsilane (GPMS), a surface modification agent, is used to give halloysite nanoparticles a hydrophobic behaviour and improve their ability to disperse in epoxy polymers (EP). Surface roughness and hydrophobicity (WCA: 144°) are both quite high in EP-GPMS/Clay coatings. The corrosion behavior of coated steel surfaces was investigated using electrochemical methods. The EP-GPMS/clay nanocomposite coating was shown to have about 63 times higher coating resistance than the EP coating. The EP-GPMS/Clay displayed better coating resistance (6687.71 kΩ.cm2) and a lower corrosion current density (4.25 μA/cm2) than plain epoxy (1.01 kΩ.cm2; 287.21 μA/cm2) even after prolonged exposure to the electrolyte, according to electrochemical studies. Compared to the pure EP (0.0599 mm/year), the EP-GPMS/clay coated sample had the lowest corrosion rate (0.0017 mm/year). According to SECM data, at 15 d of immersion, the Fe dissipation at the surface of the EP-GPMS/Clay coating (2.6 nA) is much smaller than the plain EP (14.7 nA). Additionally, the EP-GPMS/Clay showed enhanced adhesive properties. The EP with silanized clay offers an outstanding oxygen and water repellent, hydrophobic, and barrier properties. Due to the environmental safety of clay/silane, this kind of coating might be employed as a workable coating substance for industrial applications.","PeriodicalId":14778,"journal":{"name":"Journal of Adhesion","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47234394","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-26DOI: 10.1080/00218464.2022.2161898
I. Chenwi, J. Martinez, T. Ramotowski, J. LeBlanc, A. Shukla
ABSTRACT This study investigates the coupling effects of saline water and cable weight on the adhesive energy of polyurethane/Monel 400 interface using a dead weight peel test. Cables play a crucial role in naval structures serving as a central nervous system. The cables and their connectors are generally molded, encapsulated, or potted with polyurethanes to ensure that they are insulated and waterproof. During service, exposure of some of these cables and their connectors to the marine environment results in the premature failure of the polyurethane/metal interfaces of connectors. Three sets of experiments were carried out to better understand this phenomenon: an initial 90° fixed arm peel test to determine the strength of the interface, a hanging weight peel test in saline water at an elevated temperature to determine the effects of weight variation and saline water degradation, and a dead weight peel test at varying saline water temperatures to determine the acceleration factor. According to the findings, no peel was recorded in the peel experiments conducted in air indicating that the strength of the interface is higher than that of the peel arm. In the dead weight peel tests, increasing the masses of the hanging weights increased the peel velocity. Additionally, for low peel velocities, a linear relationship was observed between adhesive energy and peel velocity. Furthermore, a more cohesive primer failure was observed at the end of the peel process, indicating that peel velocity increased with longer exposure to saline water.
{"title":"Peel behavior of polyurethane/Monel 400 interface under load in saline water","authors":"I. Chenwi, J. Martinez, T. Ramotowski, J. LeBlanc, A. Shukla","doi":"10.1080/00218464.2022.2161898","DOIUrl":"https://doi.org/10.1080/00218464.2022.2161898","url":null,"abstract":"ABSTRACT This study investigates the coupling effects of saline water and cable weight on the adhesive energy of polyurethane/Monel 400 interface using a dead weight peel test. Cables play a crucial role in naval structures serving as a central nervous system. The cables and their connectors are generally molded, encapsulated, or potted with polyurethanes to ensure that they are insulated and waterproof. During service, exposure of some of these cables and their connectors to the marine environment results in the premature failure of the polyurethane/metal interfaces of connectors. Three sets of experiments were carried out to better understand this phenomenon: an initial 90° fixed arm peel test to determine the strength of the interface, a hanging weight peel test in saline water at an elevated temperature to determine the effects of weight variation and saline water degradation, and a dead weight peel test at varying saline water temperatures to determine the acceleration factor. According to the findings, no peel was recorded in the peel experiments conducted in air indicating that the strength of the interface is higher than that of the peel arm. In the dead weight peel tests, increasing the masses of the hanging weights increased the peel velocity. Additionally, for low peel velocities, a linear relationship was observed between adhesive energy and peel velocity. Furthermore, a more cohesive primer failure was observed at the end of the peel process, indicating that peel velocity increased with longer exposure to saline water.","PeriodicalId":14778,"journal":{"name":"Journal of Adhesion","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2022-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41450797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-25DOI: 10.1080/00218464.2022.2158731
Hao Li, Y. Zhu, Xianming Meng, Shipeng Li, W. Du, X. Qin
ABSTRACT The surface microstructure is one of the most important factors affecting the mechanical performance of adhesive bonding joint of CFRP materials. The aim of this paper mainly focused on the influence of laser generated microgrooves geometric parameters (groove depth, distances, and patterns) on the shearing strength of CFRP/aluminium alloy adhesive joints. An IR laser with a wavelength of 1064 nm was applied to pretreat the CFRP surface. Scanning electron microscopy (SEM) and confocal laser scanning microscope (CLSM) were used to observe and measure the surface morphology, cross-sectional shape, groove parameters (depth, width) and surface roughness. The single-lap shear experiments were also conducted to exam the quality of the adhesive joint. Meanwhile, failure modes under different groove parameters were examined using a digital camera. The main parameters of the grooves and their interaction effects on the final joint strength were quantitatively analyzed by an interactive orthogonal experimental design. It was concluded that the interaction of groove pattern and groove distance was the most significant factor affecting shear strength, followed by groove pattern and groove distance.
{"title":"Effect of laser generated microgrooves geometric parameters on the shear strength of CFRP-Aluminium alloy adhesive joints","authors":"Hao Li, Y. Zhu, Xianming Meng, Shipeng Li, W. Du, X. Qin","doi":"10.1080/00218464.2022.2158731","DOIUrl":"https://doi.org/10.1080/00218464.2022.2158731","url":null,"abstract":"ABSTRACT The surface microstructure is one of the most important factors affecting the mechanical performance of adhesive bonding joint of CFRP materials. The aim of this paper mainly focused on the influence of laser generated microgrooves geometric parameters (groove depth, distances, and patterns) on the shearing strength of CFRP/aluminium alloy adhesive joints. An IR laser with a wavelength of 1064 nm was applied to pretreat the CFRP surface. Scanning electron microscopy (SEM) and confocal laser scanning microscope (CLSM) were used to observe and measure the surface morphology, cross-sectional shape, groove parameters (depth, width) and surface roughness. The single-lap shear experiments were also conducted to exam the quality of the adhesive joint. Meanwhile, failure modes under different groove parameters were examined using a digital camera. The main parameters of the grooves and their interaction effects on the final joint strength were quantitatively analyzed by an interactive orthogonal experimental design. It was concluded that the interaction of groove pattern and groove distance was the most significant factor affecting shear strength, followed by groove pattern and groove distance.","PeriodicalId":14778,"journal":{"name":"Journal of Adhesion","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2022-12-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45693931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-22DOI: 10.1080/00218464.2022.2158084
S. Jasmee, M. Ramli, S. S. Othaman, G. Omar
ABSTRACT The demand for high thermal conductivities and improved adhesion of thermal conductive adhesives has heighten the need for hybrid fillers with extraordinary properties, such as boron nitride (BN) and graphene nanoplatelets (GNP) especially at lower filler contents (<20 wt.%), particularly with silane-functionalised BN (fBN) and adhesion using the single lap joints approach. Thus, this study was conducted to measure the thermal conductivity and shear strength of hybrid GNP with BN or fBN at different filler sizes, GNP ratios, and silane coupling agents (KK550 and KH560). We observed that the hybrid GNP/fBN_KH560 composite at a ratio of 0.75 exhibited the highest thermal conductivity and shear strength with enhancements of 198.42% and 81.82%, respectively, attributed by the high compatibility between fBN_KH560 and the polymer matrix, proven by the lowest measured contact angle and Hansen solubility parameter difference. Despite the thermal conductivity value not surpassing that of the single-filled GNP composite, the hybrid composite at lower filler content was considered a success as it exhibited a synergetic effect when compared with single-filled BN or fBN; with the difference of 0.111. Besides, crack deflection, particle debonding and pull-out mechanism improved the shear strength and promoted cohesive failure in the hybrid composite.
{"title":"Thermal conductivity and shear strength characterisation of hybrid GNPs and silane functionalised BN as thermal conductive adhesive","authors":"S. Jasmee, M. Ramli, S. S. Othaman, G. Omar","doi":"10.1080/00218464.2022.2158084","DOIUrl":"https://doi.org/10.1080/00218464.2022.2158084","url":null,"abstract":"ABSTRACT The demand for high thermal conductivities and improved adhesion of thermal conductive adhesives has heighten the need for hybrid fillers with extraordinary properties, such as boron nitride (BN) and graphene nanoplatelets (GNP) especially at lower filler contents (<20 wt.%), particularly with silane-functionalised BN (fBN) and adhesion using the single lap joints approach. Thus, this study was conducted to measure the thermal conductivity and shear strength of hybrid GNP with BN or fBN at different filler sizes, GNP ratios, and silane coupling agents (KK550 and KH560). We observed that the hybrid GNP/fBN_KH560 composite at a ratio of 0.75 exhibited the highest thermal conductivity and shear strength with enhancements of 198.42% and 81.82%, respectively, attributed by the high compatibility between fBN_KH560 and the polymer matrix, proven by the lowest measured contact angle and Hansen solubility parameter difference. Despite the thermal conductivity value not surpassing that of the single-filled GNP composite, the hybrid composite at lower filler content was considered a success as it exhibited a synergetic effect when compared with single-filled BN or fBN; with the difference of 0.111. Besides, crack deflection, particle debonding and pull-out mechanism improved the shear strength and promoted cohesive failure in the hybrid composite.","PeriodicalId":14778,"journal":{"name":"Journal of Adhesion","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2022-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43811115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-21DOI: 10.1080/00218464.2022.2160241
A. Azarhoosh, Mehdi Koohmishi, J. Vahedi
ABSTRACT Fatigue cracking is a significant cause of failure in flexible pavements at moderate temperatures. Neat bitumen cannot properly perform at all temperatures and environmental conditions due to the increasing traffic volume. Consequently, this study examined the simultaneous usage of carbon nanotubes (CNTs) and the styrene-ethylene/propylene-styrene (SEPS) polymer as bitumen modifiers. The linear amplitude sweep (LAS) test and surface free energy (SFE) theory were used to determine the rheological characteristics and thermodynamic parameters of neat and modified bitumens, respectively. Using the SEPS nanocomposite up to 6% increased the fatigue life and moisture damage resistance of the asphalt mixtures by improving thermodynamic parameters such as adhesive free energy in dry and wet conditions. According to the LAS results, the modified bitumen outperformed the neat bitumen in terms of fatigue life under different strain levels. The fatigue life of the asphalt mixtures also decreased as the temperature increased from 10 to 20°C. However, for the mixtures containing the SEPS nanocomposite, the reduction in fatigue life was less noticeable due to the lower temperature sensitivity of the modified bitumen. The mixtures containing 6% SEPS nanocomposite demonstrated the highest performance.
{"title":"Effect of carbon nanotubes on fatigue cracking of asphalt mixtures modified by styrene-ethylene/propylene-styrene","authors":"A. Azarhoosh, Mehdi Koohmishi, J. Vahedi","doi":"10.1080/00218464.2022.2160241","DOIUrl":"https://doi.org/10.1080/00218464.2022.2160241","url":null,"abstract":"ABSTRACT Fatigue cracking is a significant cause of failure in flexible pavements at moderate temperatures. Neat bitumen cannot properly perform at all temperatures and environmental conditions due to the increasing traffic volume. Consequently, this study examined the simultaneous usage of carbon nanotubes (CNTs) and the styrene-ethylene/propylene-styrene (SEPS) polymer as bitumen modifiers. The linear amplitude sweep (LAS) test and surface free energy (SFE) theory were used to determine the rheological characteristics and thermodynamic parameters of neat and modified bitumens, respectively. Using the SEPS nanocomposite up to 6% increased the fatigue life and moisture damage resistance of the asphalt mixtures by improving thermodynamic parameters such as adhesive free energy in dry and wet conditions. According to the LAS results, the modified bitumen outperformed the neat bitumen in terms of fatigue life under different strain levels. The fatigue life of the asphalt mixtures also decreased as the temperature increased from 10 to 20°C. However, for the mixtures containing the SEPS nanocomposite, the reduction in fatigue life was less noticeable due to the lower temperature sensitivity of the modified bitumen. The mixtures containing 6% SEPS nanocomposite demonstrated the highest performance.","PeriodicalId":14778,"journal":{"name":"Journal of Adhesion","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2022-12-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49542559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-11DOI: 10.1080/00218464.2022.2152333
Hasan Caglar, I. Sridhar, Mohit K. Sharma, K. Chian
ABSTRACT Prevention of mechanical and thermal damage to the composite parts is crucial during the debonding process of adhesive joints. This work highlights the impact of thermally expanded particles (TEPs) on bulk adhesive properties and the lap shear strength of adhesively bonded GFRP joints. FTIR studies revealed insignificant chemical changes occurring among the epoxy and its blend with TEPs. The addition of TEPs has slightly influenced the glass transition temperature (Tg) of adhesive. TMA showed that TEPs lose permanent expansion above maximum expansion temperature due to burst and/or diffuse of gas through the thin shell. DIC analysis of materials revealed that CTE mismatch grows with the addition of TEPs in x and y directions. Increases in TEP content up to 15 wt.% also raised the maximum dimension change in the epoxy adhesive. DMA and TGA studies indicated no major change in storage modulus and weight loss when GFRP was heated up to 170°C. The contact angle of GFRP decreased substantially after plasma surface treatment. Plasma surface treatment provided higher bond strength at room temperature than sandblasting surface treatment and prevented fiber-tearing. Despite the incorporation of TEPs, the enhanced debonding effectiveness at 145°C was marginal (less than 5%) for the epoxy adhesive used in the study. The incorporation of TEPs generated the residual stresses inside the adhesive as confirmed by measuring the residual strength of SLJ samples, especially 10 wt.% TEPs-epoxy joints exhibited more than 20% strength drop.
{"title":"Debonding of bonded composite joints with TEP modified epoxy adhesives","authors":"Hasan Caglar, I. Sridhar, Mohit K. Sharma, K. Chian","doi":"10.1080/00218464.2022.2152333","DOIUrl":"https://doi.org/10.1080/00218464.2022.2152333","url":null,"abstract":"ABSTRACT Prevention of mechanical and thermal damage to the composite parts is crucial during the debonding process of adhesive joints. This work highlights the impact of thermally expanded particles (TEPs) on bulk adhesive properties and the lap shear strength of adhesively bonded GFRP joints. FTIR studies revealed insignificant chemical changes occurring among the epoxy and its blend with TEPs. The addition of TEPs has slightly influenced the glass transition temperature (Tg) of adhesive. TMA showed that TEPs lose permanent expansion above maximum expansion temperature due to burst and/or diffuse of gas through the thin shell. DIC analysis of materials revealed that CTE mismatch grows with the addition of TEPs in x and y directions. Increases in TEP content up to 15 wt.% also raised the maximum dimension change in the epoxy adhesive. DMA and TGA studies indicated no major change in storage modulus and weight loss when GFRP was heated up to 170°C. The contact angle of GFRP decreased substantially after plasma surface treatment. Plasma surface treatment provided higher bond strength at room temperature than sandblasting surface treatment and prevented fiber-tearing. Despite the incorporation of TEPs, the enhanced debonding effectiveness at 145°C was marginal (less than 5%) for the epoxy adhesive used in the study. The incorporation of TEPs generated the residual stresses inside the adhesive as confirmed by measuring the residual strength of SLJ samples, especially 10 wt.% TEPs-epoxy joints exhibited more than 20% strength drop.","PeriodicalId":14778,"journal":{"name":"Journal of Adhesion","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2022-12-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45854043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-12-08DOI: 10.1080/00218464.2022.2153676
H. Shinde, Nikhil Sonawane, M. Karnik, Prashanth Kumar
ABSTRACT Thin panels of aluminium alloy 6061-T6 with a centre pre-crack were repaired with a one-sided asymmetrical CFRP patch through co-curing of epoxy at the room temperature to have minimal residual stresses. The specimens were tested with a tension-tension fatigue load. The numerical simulation as well as the experiments showed that the fatigue life was improved considerably with the increasing patch length when tested at room temperature. In the asymmetrical repair with a single patch, a bending moment was induced whose magnitude decreased with the increasing patch length, resulting into longer fatigue life. The specimens failed through the growth of the pre-crack in the skin. However, the crack in the skin did not grow in case of the specimen with the longest patch length and the failure occurred at substantially higher number of fatigue cycles through a different mechanism in the bare portion of the aluminium alloy skin. Experiments were also conducted at the elevated temperature of 80°C. Thermal compressive stresses were developed in the aluminium alloy panel due to the vast difference in the coefficient of thermal expansion of the aluminium alloy and the CFRP patch. Consequently, the stress intensity factor of the crack in the aluminium panel was reduced considerably, resulting into the increase of the fatigue failure life significantly.
{"title":"Effect of patch length and elevated temperature on fatigue behaviour of repaired aluminium panels with a CFRP patch","authors":"H. Shinde, Nikhil Sonawane, M. Karnik, Prashanth Kumar","doi":"10.1080/00218464.2022.2153676","DOIUrl":"https://doi.org/10.1080/00218464.2022.2153676","url":null,"abstract":"ABSTRACT Thin panels of aluminium alloy 6061-T6 with a centre pre-crack were repaired with a one-sided asymmetrical CFRP patch through co-curing of epoxy at the room temperature to have minimal residual stresses. The specimens were tested with a tension-tension fatigue load. The numerical simulation as well as the experiments showed that the fatigue life was improved considerably with the increasing patch length when tested at room temperature. In the asymmetrical repair with a single patch, a bending moment was induced whose magnitude decreased with the increasing patch length, resulting into longer fatigue life. The specimens failed through the growth of the pre-crack in the skin. However, the crack in the skin did not grow in case of the specimen with the longest patch length and the failure occurred at substantially higher number of fatigue cycles through a different mechanism in the bare portion of the aluminium alloy skin. Experiments were also conducted at the elevated temperature of 80°C. Thermal compressive stresses were developed in the aluminium alloy panel due to the vast difference in the coefficient of thermal expansion of the aluminium alloy and the CFRP patch. Consequently, the stress intensity factor of the crack in the aluminium panel was reduced considerably, resulting into the increase of the fatigue failure life significantly.","PeriodicalId":14778,"journal":{"name":"Journal of Adhesion","volume":null,"pages":null},"PeriodicalIF":2.2,"publicationDate":"2022-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47546176","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-11-30DOI: 10.1080/00218464.2022.2152677
B. Simões, P. Nunes, B. Henriques, E. Marques, R. Carbas, L. D. da Silva
ABSTRACT The Mode I fracture behaviour of adhesive joints, bonded with two different epoxies, was evaluated applying the direct method to obtain the tensile cohesive law, together with Digital Image Correlation (DIC) analysis. The Double Cantilever Beam (DCB) test was performed, and the fracture toughness was attained by applying the J-integral. The DIC measurements were analysed resorting to a Python script, that was used as a post-processing tool, able to minimize the data noise stemming from the experimental results. This tool proved to be of utmost importance to guarantee acceptable results. Finally, the direct method could predict the main features of the cohesive law. Also, the law was used to simulate the fracture behaviour in a different test specimen, to evaluate the influence of the specimen geometry on the results. The obtained data indicates that the direct method is dependent on the joint geometry and the constraining condition of the adhesive.
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