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Previous studies have provided evidence that reinforcement of epoxy adhesives with nanostructures such as carbon nanofibers (CNFs) produces higher strength bonded joints between carbon fiber reinforced polymer (CFRP) laminates and shifts bond-line failure modes from the adhesive into the laminate. Despite this, there has been no research dedicated to applying reinforced adhesives to the bonding of nano-reinforced CFRP such as CNF z-threaded carbon fiber reinforced polymer (ZT-CFRP) laminates, which have been proven to exhibit increased interlaminar shear strength, mode-I delamination toughness, and compressive strength over traditional CFRP. This study examined the effectiveness of using CNF reinforced epoxy adhesives for unidirectional ZT-CFRP laminate bonding through single-lap shear tests using the ASTM D5868-01 standard. Unidirectional CFRP laminate samples bonded with both epoxy adhesive and CNF reinforced epoxy adhesive were also tested for comparison. It was found that the average shear strength observed for ZT-CFRP samples bonded with CNF reinforced epoxy adhesive was approximately 44% and 26 % higher than that of CFRP samples bonded with epoxy adhesive and CNF reinforced epoxy adhesive, respectively. Microscopic image analysis was performed to examine the mode of bond failure. The roles of nanomaterials in the fracture mechanism of the adhesives and the composite laminates are also discussed.
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Study of Adhesive Joints Quality Based on Multi-Camera DIC System
Abstract Carbon and glass fiber-reinforced plastic (CFRP and GFRP) composites have gained popularity in various industries and settings owing to their exceptional strength-to-weight ratio, corrosion resistance, fatigue resistance, and design flexibility. Adhesives are commonly utilized to bond carbon fiber reinforced plastics to other materials or to themselves. Bonded joints have been found to enhance the mechanical characteristics of materials, while also reducing additional costs for practical applications. The bonding region’s strength can be influenced by different material combinations and substrate thicknesses. The present investigation employed a double-sided multi-digital image correlation (DS-Multi-DIC) system to quantify the deformation and fracture mechanisms of adherends during tensile testing. The primary objective was to assess the static impact on the strength of the bonded zone under tensile loading. The system comprises of two stereo vision DIC measurement systems, wherein each system comprises of two GigE cameras. These cameras are positioned at the front and back of the sample, respectively the process of system calibration involves the utilization of the double-sided calibration technique to integrate the coordinate systems of the two DIC measurement subsystems with the global coordinate system. This enables the direct measurement of deformation and strain in three dimensions. This paper examines the impact of adhesive thickness and type on the strength of the bonded area and fracture mechanism by analyzing the alteration in strain distribution and maximum strain during static stretching. The study yielded a conclusion that the magnitude of the bonded region’s strength is positively correlated with the thickness of the bonding material. The cohesive force of the bonded region is positively correlated with the malleability of the adhesive bond. Furthermore, an examination was conducted on the impact of adhesive thickness and type on peeling strain. As the bond’s bending stiffness diminishes, there is a corresponding increase in the peel strain it undergoes. Furthermore, a succinct description is provided regarding the unequal allocation of auditory alterations that occur during stationary stretching.
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- Award ID(s):
- 2052658
- PAR ID:
- 10518351
- Publisher / Repository:
- American Society of Mechanical Engineers
- Date Published:
- ISBN:
- 978-0-7918-8760-8
- Format(s):
- Medium: X
- Location:
- New Orleans, Louisiana, USA
- Sponsoring Org:
- National Science Foundation
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