scholarly journals Experimental investigation on stiffness and strength of single-lap z-pinned joints in a laminated CFRP stress-ribbon strip

2016 ◽  
Vol 11 (2) ◽  
pp. 120-126 ◽  
Author(s):  
Aleksandr K. Arnautov ◽  
Vladimir Kulakov ◽  
Janis Andersons ◽  
Viktor Gribniak ◽  
Algirdas Juozapaitis
Keyword(s):  
Structural Integrity ◽  
Progressive Failure ◽  
Failure Process ◽  
High Strength ◽  
Lap Joints ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Reinforced Polymers ◽  
Load Bearing ◽  
Hybrid Joints

Carbon fiber-reinforced polymer (carbon-polymer) is an advanced lightweight composite material with high strength and excellent resistance to corrosion and fatigue. Over the past decades, application of fiber-reinforced polymers has been spread from the aerospace to other branches of industry such as automobile and civil engineering. Unidirectional carbon-polymers have a high potential for replacing steel in tensile members. Recently, the first carbonpolymer stress-ribbon bridge has been constructed in Germany. The non-laminated strip-loop carbon-polymer thin strips were used as the load bearing components in this bridge. In comparison with the laminated components, the applied cables are characterized by a more uniform strain distribution though reduced structural integrity. Alternative jointing technologies of carbon-polymer laminates are considered in this paper with an intention to increase the structural integrity and reliability of the production. Tensile behavior of the single-lap joints was investigated experimentally. Three types of the joints were considered. Adhesive joint was set as the reference. The overlap region of the mechanically fastened joints was produced using 9, 25, or 36 steel needles (z-pins) of 1 mm diameter. The proposed hybrid joints were additionally connected with adhesive increasing the load-bearing capacity of the reference joint up to 230%. Concerning the brittle fracture of the adhesive counterparts, the extended progressive failure process within the hybrid joints is responsible for the improvement.

Behavior of Rectangular Concrete Column Confined with Sisal Fiber Reinforced Polymers (Sisal FRP)

2016 ◽  
Vol 860 ◽  
pp. 140-143 ◽  
Author(s):  
Atipphat Suwattanakorn ◽  
Qudeer Hussain ◽  
Winyu Rattanapitikon ◽  
Amorn Pimanmas
Keyword(s):  
Research Work ◽  
Testing Machine ◽  
High Strength ◽  
Fiber Reinforced Polymers ◽  
Sisal Fiber ◽  
Fiber Reinforced ◽  
Concrete Core ◽  
Reinforced Polymers ◽  
Rectangular Columns ◽  
Strength And Ductility

This research work presents the results of experiment study on the axial behavior of low-high strength concrete rectangular columns confined by Sisal Fiber Reinforced Polymers (Sisal FRP). The objective of this study is investigate the performance of Sisal FRP composites to increase strength and ductility of rectangular columns through external confinement. The research parameter were confinement thickness and strength of concrete core. A total of 16 rectangular columns were tested under Universal Testing Machine (UTM) up to failure point. Test result shown that the external confinement by Sisal FRP are very effective to increase strength and ductility.

scholarly journals Quantification of the Effects of Strain Rate and Nano-Reinforcement on the Performance of Adhesively Bonded Single-Lap Joints

2020 ◽  
Vol 8 (2) ◽  
pp. S1-S19
Author(s):  
B. Soltannia ◽  
K. Duke ◽  
F. Taheri ◽  
P. Mertiny
Keyword(s):  
Strain Rate ◽  
Weight Percent ◽  
Lap Joints ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Adhesively Bonded ◽  
Ultimate Shear Strength ◽  
Carbon Fiber Reinforced Polymers ◽  
Reinforced Polymers ◽  
Single Lap Joints

The aim of this study is to present an efficient and effective technique to strategically investigate and classify the influence of a set of manipulated parameters that affect the mechanical properties and performance of adhesively bonded joints formed by an adhesive that is reinforced by various types of carbon nanoparticles (NPs). Specifically, single-lap joints (SLJs) are considered in this study. The selected parameters include the adherend types (i.e., carbon fiber-reinforced polymers (CFRPs) and glass fiber-reinforced polymers (GFRPs)), three types of nanoparticles (i.e., carbon nanofibers (CNFs), multi-walled carbon nanotubes (MWCNTs) and graphene nanoplatelets (GNPs)), different weight-percent (wt.%) of GNPs (i.e., 0, 0.5, 1%), and three different strain (or loading) rates, classified as static, quasi-static and impact loadings, herein. The study employed two mixed-level full factorial design of experiments (DOE) to evaluate the contribution of the aforementioned parameters, including the effect of their interactions on the enhancement of the averaged ultimate shear strength (AUSS) of the SLJs. The DOE study was conducted using the strength data (AUSS) obtained through testing of 108 SLJ specimens. The results indicate that among the considered parameters, NPs (wt%), adherend type, and strain rate had a greater effect on AUSS. According to the DOE conducted in this study, the greatest AUSS (19.9 MPa) could be obtained when 1.0 wt% GNP was used to reinforce the SLJs with CFRP adherend and subjected to the highest strain rate (HSR). This combination yielded a 32% enhanced AUSS compared to the SLJs formed by the neat adhesive.

scholarly journals LIGHTENING STRUCTURES BY METAL REPLACEMENT: FROM TRADITIONAL GYM EQUIPMENT TO AN ADVANCED FIBER-REINFORCED COMPOSITE EXOSKELETON

2021 ◽  
Vol 19 (2) ◽  
pp. 155
Author(s):  
Cristiano Fragassa
Keyword(s):  
Composite Laminates ◽  
Volume Ratio ◽  
Kinematic Chain ◽  
High Strength ◽  
Failure Criteria ◽  
Maximum Principal Stress ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Reinforced Polymers ◽  
Strain Behavior

A redesign procedure used for introducing new functional properties in innovative gym equipment is here reported. It is based on a metal replacement action where a tempered steel was firstly replaced by an aluminum alloy and then by high strength-to-weight fiber-reinforced polymers. The effect of fiber properties (as strength and volume ratio) and plies stacking sequences (as thicknesses and orientation) were investigated. Numerical analyses, done by Ansys ACP, allowed evaluating the stress-strain behavior in realistic boundaries and quasi-static loads, comparing materials and layouts in terms of stiffness. The single-layered shell method with additional integration points was preferred as a technique for discretizing composite laminates. Maximum Principal Stress and Maximum Distortion Energy (Tsai-Hill) were applied as anisotropic failure criteria. Changes in geometry were also considered given their relevant effects on parts and processes. Specifically, this paper is focused on a representative component of the main kinematic chain (the ‘forearm’) and details the different redesign phases for that part. The chosen solution consisted of 14 layers of unidirectional and bidirectional carbon fiber-reinforced pre-pregs, offering a 68 % weight reduction with respect to a solid aluminum component with equal stiffness. The part was manufactured by hand lay-up and cured in autoclave. This redesign practice was extended to the rest of the equipment allowing its transformation into an exoskeleton.

scholarly journals Maintenance and Inspection of Fiber-Reinforced Polymer (FRP) Bridges: A Review of Methods

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7826
Author(s):  
Long Tang
Keyword(s):  
Building Materials ◽  
High Strength ◽  
Fiber Reinforced Polymers ◽  
Fiber Reinforced ◽  
Reinforced Polymers ◽  
Reinforced Polymer ◽  
Static And Dynamic Loads ◽  
Potential Damage ◽  
Maintenance And Inspection

Fiber-reinforced polymers (FRPs) are materials that comprise high-strength continuous fibers and resin polymer, and the resins comprise a matrix in which the fibers are embedded. As the technique of FRP production has advanced, FRPs have attained many incomparable advantages over traditional building materials such as concrete and steel, and thus they play a significant role in the strengthening and retrofitting of concrete structures. Bridges that are built out of FRPs have been widely used in overpasses of highways, railways and streets. However, damages in FRP bridges are inevitable due to long-term static and dynamic loads. The health of these bridges is important. Here, we review the maintenance and inspection methods for FRP structures of bridges and analyze the advantages, shortcomings and costs of these methods. The results show that two categories of methods should be used sequentially. First, simple methods such as visual inspection, knock and dragging-chain methods are used to determine the potential damage, and then radiation, modal analysis and load experiments are used to determine the damage mode and degree. The application of FRP is far beyond the refurbishment, consolidation and construction of bridges, and these methods should be effective to maintain and inspect the other FRP structures.

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