The flexural behaviors of the impacted composite single-lap adhesive joints

2015 ◽  
Vol 22 (5) ◽  
Author(s):  
Emin Ergun ◽  
Hasan Çallioğlu
Keyword(s):  
Experimental Study ◽  
Impact Energy ◽  
Energy Levels ◽  
Composite Plates ◽  
Lap Joints ◽  
Adhesive Joints ◽  
Single Lap Joints ◽  
Impact Tests ◽  
Impact Energies ◽  
The Impact

AbstractThis experimental study deals with the flexural behaviors of composite single-lap adhesive joints after impact tests. Increasing impact energies are applied at the center of the composite plates having three different overlap lengths. It is shown that the overlap lengths and impact energy levels affect considerably the impact responses of the composite single-lap joints. It is also shown that the bending stiffness of the composite increases with increasing overlap length. For this reason, after the impact tests, how these effects influence the flexural behaviors of the impacted composite lap joints was also investigated. The flexural loads of the impacted and non-impacted composite single-lap joints were determined and compared with each other. It is shown that the residual flexural loads after impact increase with increasing overlap lengths but decrease with increasing impact energy.

An Assesment of the Impacted Composite Single-Lap Adhesive Joints

2015 ◽  
Vol 31 (4) ◽  
pp. 433-439
Author(s):  
H. Çallioğlu ◽  
E. Ergun
Keyword(s):  
Experimental Study ◽  
Impact Energy ◽  
Energy Levels ◽  
Composite Plates ◽  
Lap Joints ◽  
Adhesive Joints ◽  
Single Lap Joints ◽  
Impact Energies ◽  
The Impact ◽  
Energy Profiling

AbstractThe aim of this experimental study is to investigate impact behaviors of the composite single-lap adhesive joints. The increasing impact energies, which are ranged from approximately 5 J to 30 J, are performed at the center of the composite plates having three different overlap lengths. It is shown that the overlap lengths and impact energy levels affect considerably the impact responses of the composite single lap joints. It is also shown that the bending stiffness of the composite increases by increase in the overlap length. An energy profiling method (EPM) is used to identify the penetration and perforation thresholds of composite lap joints. The damaged composite plates are visually inspected.

scholarly journals Experimental and Numerical Study of Low-Velocity Impact and Tensile after Impact for CFRP Laminates Single-Lap Joints Adhesively Bonded Structure

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1016
Author(s):  
Chunxing Hu ◽  
Guibin Huang ◽  
Cheng Li
Keyword(s):  
Lap Joints ◽  
Low Velocity Impact ◽  
Adhesively Bonded ◽  
Low Velocity ◽  
Adhesive Film ◽  
Velocity Impact ◽  
Cfrp Laminates ◽  
Single Lap Joints ◽  
Impact Energies ◽  
The Impact

To investigate the mechanical behavior of the single-lap joints (SLJs) adhesively bonded structure of carbon fiber reinforced polymer (CFRP) laminates under the low-velocity impact (LVI) and tensile-after impact (TAI), tests and simulations were carried out. A finite element model (FEM) was established based on the cohesive zone model (CZM) and Hashin criterion to predict the damage evolution process of adhesive film, intra- and inter-laminar of the SLJs of CFRP laminates, and its effectiveness was verified by experiments. Moreover, three different overlap lengths (20 mm, 30 mm, and 40 mm) and four different impact energies (Intact joint, 10 J, 20 J, and 30 J) are considered in the present study. Finally, the effects of different impact energies and overlap lengths on the residual strength of SLJs after impact were discussed. The results divulged that numerical results of impact and TAI processes of SLJs were in good agreement with experiment results. During the impact process, the damage of the laminates was primarily fiber and matrix tensile damage, whereas the adhesive film was damaged cohesively; the areas of damage increased with the increase of impact energy, and the normal stress of the adhesive film expanded from the edge to the middle region with the increase of impact force. The influence of LVI on SLJs adhesively bonded structures was very significant, and it is not effective to obtain a higher impact resistance by increasing the overlap length. For the tensile process, the failure mode of TAI of the SLJs was interface failure, the surplus strength of the SLJs gradually decreased with the increase of the impact energy because of the smaller overlap length, the overlap length more than 30 mm, and the low energy impact has almost no effect on the residual strength of the SLJs.

Effects of impact fatigue on residual static strength of adhesively bonded joints

2021 ◽  
pp. 146442072199487
Author(s):  
S. Jalali ◽  
M.R. Ayatollahi ◽  
A. Akhavan-Safar ◽  
L.F.M. da Silva
Keyword(s):  
Energy Levels ◽  
Microscopic Analysis ◽  
Industrial Applications ◽  
Static Strength ◽  
Lap Joints ◽  
Impact Fatigue ◽  
Adhesively Bonded ◽  
Single Lap Joints ◽  
Cyclic Impact ◽  
The Impact

In most industrial applications, adhesive joints experience impact fatigue loads in service. The energy of each impact is too low to cause joint failure. Although the repetitive impacts usually do not apparently affect the joints, they can significantly reduce the strength of adhesively bonded structures. Accordingly, understanding the effect of impact fatigue on the residual strength of the bonded components is crucial in real applications. This study deals with this issue where the effect of impact fatigue on the residual static strength of single lap joints is analyzed. To achieve this, the manufactured single lap joints were categorized into four different groups. Group 1 joints were tested under static loading conditions. Joints in group 2 were tested under impact to obtain the impact strength of the single lap joints. To analyze the impact fatigue life of the joints, the single lap joints in group 3 were tested under cyclic impact at different energy levels until failure. To investigate the effect of impact fatigue on the residual static strength of the joints, single lap joints in group 4 were tested under a specific number of impact cycles followed by a static tensile test. Using microscopic analysis, the fracture surfaces of the tested specimens were analyzed. The results showed that cracks initiate from the middle of the bonded area as a result of cyclic impact stress waves. Then, by increasing the number of impacts, a large number of cracks nucleate from the edges of the joints and grow along the width to the middle of the overlap. A 3D finite element method was employed to analyze the stress distribution along the bondline under impact loads.

The Effect of the Boundary Conditions on the Impact Behaviors of Stitched Composite Lap Joints

2016 ◽  
Vol 25 (1) ◽  
pp. 096369351602500
Author(s):  
Emin Ergun ◽  
Ismail Gökkaya
Keyword(s):  
Boundary Conditions ◽  
Energy Levels ◽  
Composite Plates ◽  
Lap Joints ◽  
Transverse Impact ◽  
Adhesively Bonded ◽  
Bonded Composite ◽  
Infusion Method ◽  
Impact Characteristics ◽  
The Impact

In this study, transverse impact behaviors of stitch adhesively bonded composite lap joints having three different overlap lengths (20, 40 and 60 mm) at different energy levels are investigated. The effects of the boundary conditions (clamped-clamped and clamped-free) and three different span lengths (40, 60 and 80 mm) have been determined. The impacts energies are varied in a range from 5 J to 20 J. Vacuum assisted resin infusion method (VARIM) is used to manufacture composite plates. It is shown that the boundary conditions and span lengths affect considerably the impact responses of the stitch composites lap joints. The important impact characteristics of the composite lap joints are compared with each other and discussed. The observed damages of the composite lap joints are presented.

scholarly journals An Experimental Investigation on the Impact Behaviour of Glass/Epoxy and Hybrid Composite Plates

2009 ◽  
Vol 18 (4) ◽  
pp. 096369350901800 ◽  
Author(s):  
Metin Sayer ◽  
Numan B. Bektaş ◽  
Onur Sayman ◽  
Muzaffer Topçu
Keyword(s):  
Cross Sections ◽  
Impact Energy ◽  
Hybrid Composite ◽  
Composite Plates ◽  
Glass Carbon ◽  
Extent Of Damage ◽  
Impact Energies ◽  
The Impact ◽  
The Relationship ◽  
Energy Profiling

In this study, the impact behaviours of glass/epoxy and hybrid (glass-carbon/epoxy) composite plates have been investigated experimentally. The increasing impact energy was performed on composite plates until complete perforation of samples. An energy profiling diagram, showing the relationship between impact energy and absorbed energy, was used together with load-deflection curves to determine the penetration and perforation thresholds of composite plates. The failure processes of damaged specimens for different impact energies were evaluated by comparing load-deflection curves and images of damaged samples taken from impacted sides and non-impacted sides. Cross-sections of damaged specimens for both plates were also inspected visually and discussed to assess the extent of damage, such as fibre fracture in layers, expansion of delaminations between adjacent layers. The perforation threshold of hybrid composite impacted from surface with carbon fibres was found approximately 30% and 15% higher than those of surface with glass fibres of hybrid plates and glass/epoxy plates, respectively.

scholarly journals Experimental Study of the Influence of the Surface Preparation on the Fatigue Behavior of Polyamide Single Lap Joints

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1008
Author(s):  
Francesco Musiari ◽  
Fabrizio Moroni
Keyword(s):  
Experimental Study ◽  
Fatigue Behavior ◽  
Atmospheric Pressure Plasma ◽  
Surface Preparation ◽  
Lap Joints ◽  
Polymeric Surfaces ◽  
Adhesively Bonded Joints ◽  
Single Lap Joints ◽  
Number Of Cycles ◽  
Structural Adhesive

The low quality of adhesion performance on polymeric surfaces has forced the development of specific pretreatments able to toughen the interface between substrate and adhesive. Among these methods, atmospheric pressure plasma treatment (APPT) appears particularly suitable for its environmental compatibility and its effectiveness in altering the chemical state of the surface. In this work, an experimental study on adhesively bonded joints realized using polyamide as substrates and polyurethane as the structural adhesive was carried out with the intent to characterize their fatigue behavior, which represents a key issue of such joints during their working life. The single lap joint (SLJ) geometry was chosen and several surface pretreatments were compared with each other: degreasing, abrasion (alone and followed by APPT) and finally APPT. The results show that the abrasion combined with APPT presents the most promising behavior, which appears consistent with the higher percentage of life spent for crack propagation found by means of DIC on this class of joints with respect to the others. APPT alone confers a good fatigue resistance with respect to the simple abrasion, especially at a low number of cycles to failure.

scholarly journals Strength and Failure Mechanism of Composite-Steel Adhesive Bond Single Lap Joints

2018 ◽  
Vol 2018 ◽  
pp. 1-10
Author(s):  
Kai Wei ◽  
Yiwei Chen ◽  
Maojun Li ◽  
Xujing Yang
Keyword(s):  
Failure Mechanism ◽  
Shear Failure ◽  
Failure Load ◽  
Lap Joints ◽  
Adhesive Joints ◽  
Adhesive Failure ◽  
Interface Failure ◽  
Element Analysis ◽  
Single Lap Joints ◽  
Structural Adhesive

Carbon fiber-reinforced plastics- (CFRP-) steel single lap joints with regard to tensile loading with two levels of adhesives and four levels of overlap lengths were experimentally analyzed and numerically simulated. Both joint strength and failure mechanism were found to be highly dependent on adhesive type and overlap length. Joints with 7779 structural adhesive were more ductile and produced about 2-3 kN higher failure load than MA830 structural adhesive. Failure load with the two adhesives increased about 147 N and 176 N, respectively, with increasing 1 mm of the overlap length. Cohesion failure was observed in both types of adhesive joints. As the overlap length increased, interface failure appeared solely on the edge of the overlap in 7779 adhesive joints. Finite element analysis (FEA) results revealed that peel and shear stress distributions were nonuniform, which were less severe as overlap length increased. Severe stress concentration was observed on the overlap edge, and shear failure of the adhesive was the main reason for the adhesive failure.

Response of Mild Steel Pipes Under High Mass Low Velocity Impacts

2014 ◽  
Author(s):  
Shamsoon Fareed ◽  
Ian May
Keyword(s):  
Finite Element ◽  
Mild Steel ◽  
Impact Energy ◽  
High Mass ◽  
Low Velocity ◽  
Element Analysis ◽  
Steel Pipes ◽  
Impact Tests ◽  
The Finite Element Analysis ◽  
The Impact

Accidental loads, for example, due to heavy dropped objects, impact from the trawl gear and anchors of fishing vessels can cause damage to pipelines on the sea bed. The amount of damage will depend on the impact energy. The indentation will be localized at the contact area of the pipe and the impacting object, however, an understanding of the extent of the damage due to an impact is required so that if one should occur in practice an assessment can be made to determine if remedial action needs to be taken to ensure that the pipeline is still serviceable. There are a number of parameters, including the pipe cross section and impact energy, which influence the impact behaviour of a pipe. This paper describes the response, and assesses the damage, of mild steel pipes under high mass low velocity impacts. For this purpose full scale impacts tests were carried out on mild steel pipe having diameter of 457 mm, thickness of 25.4 mm and length of 2000 mm. The pipe was restrained along the base and a 2 tonnes mass with sharp impactor having a vertical downward velocity of 3870 mm/sec was used to impact the pipe transversely with an impact energy of 16 kJ. It was found from the impact tests that a smooth indentation was produced in the pipe. The impact tests were then used for validation of the non-linear dynamic implicit analyses using the finite element analysis software ABAQUS. Deformations at the impact zone, the rebound velocity, etc, recorded in the tests and the results of the finite element analysis were found to be in good agreement. The impact tests and finite element analyses described in this paper will help to improve the understanding of the response of steel pipes under impact loading and can be used as a benchmark for further finite element modelling of impacts on pipes.

Failure analysis of simple overlap bonding joints and numerical investigation of the adhered tip geometry effect on the joint strength

2021 ◽  
Vol 63 (11) ◽  
pp. 1007-1011
Author(s):  
İsmail Saraç
Keyword(s):  
Finite Element Analysis ◽  
Experimental Study ◽  
Finite Element ◽  
Reference Model ◽  
Lap Joints ◽  
Shear Stresses ◽  
Element Analysis ◽  
Single Lap Joints ◽  
Failure Loads ◽  
Previous Experimental Study

Abstract This study was carried out in two stages. In the first step, a numerical study was performed to verify the previous experimental study. In accordance with the previous experimental study data, single lap joints models were created using the ANSYS finite element analysis program. Then, nonlinear stress and failure analyses were performed by applying the failure loads obtained in the experimental study. The maximum stress theory was used to find finite element failure loads of the single lap joints models. As a result of the finite element analysis, an approximate 80 % agreement was found between experimental and numerical results. In the second step of the study, in order to increase the bond strength, different overlap end geometry models were produced and peel and shear stresses in the adhesive layer were compared according to the reference model. As a result of the analyses, significant strength increases were calculated according to the reference model. The strength increase in model 3 and model 5 was found to be 80 % and 67 %, respectively, relative to the reference model.

Directly bonded single lap joints of SiCp/AA2124 composite with glass fiber-reinforced polypropylene: Hole drilling effects on lap shear strength and out-of-plane impact response

2021 ◽  
pp. 002199832110316
Author(s):  
Nahit Öztoprak
Keyword(s):  
Glass Fiber ◽  
Matrix Composite ◽  
Lap Joints ◽  
Hole Drilling ◽  
Fiber Reinforced ◽  
Single Lap Joints ◽  
Lap Shear ◽  
Glass Fiber Reinforced ◽  
Out Of Plane ◽  
The Impact

Joining dissimilar materials to achieve lightweight design and energy efficiency has been increasingly popular. A joint formed by components of particle-reinforced metal and polymer matrix composite combines the merits of both materials. This paper is mainly focused on the research of the tensile lap shear and impact behavior of the dissimilar single-lap joints (SLJs) between SiCp/AA2124 composite and glass fiber-reinforced polypropylene (PP). The effects of out-of-plane loading applied from different surfaces of SLJs on impact responses are evaluated. Hot pressing technique is introduced to manufacture metal/polymer assembly without using any adhesive. The hole drilling effect is investigated with the idea that it may provide weight reduction and also increase the strength of the dissimilar SLJs. The results indicate that the dissimilar SLJs show more Charpy impact strength when the impact is performed on the metal-matrix composite (MMC). Mechanical properties of SLJs are adversely affected by a drilled hole in the MMC adherend.

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