scholarly journals An Experimental and Numerical Study of Repairs on Composite Substrates with Composite and Aluminum Doublers Using Riveted, Bonded, and Hybrid Joints

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 2978 ◽  
Author(s):  
Pitta ◽  
Roure ◽  
Crespo ◽  
Rojas
Keyword(s):  
Composite Structures ◽  
Failure Modes ◽  
Numerical Study ◽  
Progressive Failure ◽  
Adhesive Bond ◽  
Element Analysis ◽  
Fea Model ◽  
Composite Substrate ◽  
Riveted Joints ◽  
Hybrid Joints

In this work, experimental and numerical analyses of repairs on carbon fiber reinforced epoxy (CFRE) substrates, with CFRE and aluminum alloy doublers typical of aircraft structures, are presented. The substrates have a bridge gap of 12.7 mm (simulated crack), repaired with twin doublers joined with riveted, adhesive bonded, and hybrid joints. The performance of the repairs using different doubler materials and joining techniques are compared under static loading. The experimental results show that riveted joints have the lowest strength, while adhesive bonded joints have the highest strength, irrespective of the doubler material. Finite element analysis (FEA) of the studied joints is also performed using commercial FEA tool Abaqus. In the FEA model, point-based fasteners are used for the rivets, and a cohesive zone contact model is used to simulate the adhesive bond. The FEA results indicate that the riveted joints have higher tensile stresses on the metal doublers compared to the composite doublers. As per the failure modes, interestingly, for hybrid joints using composite doublers, the doublers fail due to net-section failure, while, for hybrid joints using metal doublers, it is the composite substrate that fails due to net-section failure. This suggests vulnerability of the composite structures to mechanical fastener holes. Lastly, the Autodesk Helius composite tool is used for prediction of first-ply failure and ply load distribution, and for progressive failure analysis of the composite substrate.

scholarly journals Strength Prediction of Adhesively-Bonded Scarf Repairs in Composite Structures under Bending

2010 ◽  
Vol 636-637 ◽  
pp. 233-238 ◽  
Author(s):  
Raul D.S.G. Campilho ◽  
Marcelo F.S.F. de Moura ◽  
A.M.G. Pinto ◽  
Dimitra A. Ramantani ◽  
J.J.L. Morais ◽  
...  
Keyword(s):  
Composite Structures ◽  
Mixed Mode ◽  
Failure Modes ◽  
Numerical Study ◽  
Adhesive Layer ◽  
Elastic Stiffness ◽  
Cohesive Elements ◽  
Adhesively Bonded ◽  
Element Analysis ◽  
Cohesive Laws

This work reports on the experimental and numerical study of the bending behaviour of two-dimensional adhesively-bonded scarf repairs of carbon-epoxy laminates, bonded with the ductile adhesive Araldite 2015®. Scarf angles varying from 2 to 45º were tested. The experimental work performed was used to validate a numerical Finite Element analysis using ABAQUS® and a methodology developed by the authors to predict the strength of bonded assemblies. This methodology consists on replacing the adhesive layer by cohesive elements, including mixed-mode criteria to deal with the mixed-mode behaviour usually observed in structures. Trapezoidal laws in pure modes I and II were used to account for the ductility of the adhesive used. The cohesive laws in pure modes I and II were determined with Double Cantilever Beam and End-Notched Flexure tests, respectively, using an inverse method. Since in the experiments interlaminar and transverse intralaminar failures of the carbon-epoxy components also occurred in some regions, cohesive laws to simulate these failure modes were also obtained experimentally with a similar procedure. A good correlation with the experiments was found on the elastic stiffness, maximum load and failure mode of the repairs, showing that this methodology simulates accurately the mechanical behaviour of bonded assemblies.

scholarly journals Design and analysis of concrete-filled tubular flange girders under combined loading

2021 ◽  
pp. 136943322110015
Author(s):  
Rana Al-Dujele ◽  
Katherine Ann Cashell
Keyword(s):  
Finite Element ◽  
Axial Force ◽  
Failure Modes ◽  
Numerical Study ◽  
Combined Loading ◽  
Torsional Stiffness ◽  
Fe Model ◽  
Combined Effects ◽  
Element Analysis ◽  
Hollow Section

This paper is concerned with the behaviour of concrete-filled tubular flange girders (CFTFGs) under the combination of bending and tensile axial force. CFTFG is a relatively new structural solution comprising a steel beam in which the compression flange plate is replaced with a concrete-filled hollow section to create an efficient and effective load-carrying solution. These members have very high torsional stiffness and lateral torsional buckling strength in comparison with conventional steel I-girders of similar depth, width and steel weight and are there-fore capable of carrying very heavy loads over long spans. Current design codes do not explicitly include guidance for the design of these members, which are asymmetric in nature under the combined effects of tension and bending. The current paper presents a numerical study into the behaviour of CFTFGs under the combined effects of positive bending and axial tension. The study includes different loading combinations and the associated failure modes are identified and discussed. To facilitate this study, a finite element (FE) model is developed using the ABAQUS software which is capable of capturing both the geometric and material nonlinearities of the behaviour. Based on the results of finite element analysis, the moment–axial force interaction relationship is presented and a simplified equation is proposed for the design of CFTFGs under combined bending and tensile axial force.

Progressive failure analysis of fiber-reinforced laminated composites containing a hole

2017 ◽  
Vol 27 (7) ◽  
pp. 963-978 ◽  
Author(s):  
Hadi Bakhshan ◽  
Ali Afrouzian ◽  
Hamed Ahmadi ◽  
Mehrnoosh Taghavimehr
Keyword(s):  
Failure Analysis ◽  
Failure Modes ◽  
Progressive Failure ◽  
Composite Plates ◽  
Failure Criteria ◽  
Element Analysis ◽  
Progressive Failure Analysis ◽  
Numerical Predictions ◽  
Open Hole ◽  
Failure Loads

The present work aims to obtain failure loads for open-hole unidirectional composite plates under tensile loading. For this purpose, a user-defined material model in the finite element analysis package, ABAQUS, was developed to predict the failure load of the open-hole composite laminates using progressive failure analysis. Hashin and modified Yamanda-Sun’s failure criteria with complete and Camanho’s material degradation model are studied. In order to achieve the most accurate predictions, the influence of failure criteria and property degradation rules are investigated and failure loads and failure modes of the composites are compared with the same experimental test results from literature. A good agreement between experimental results and numerical predictions was observed.

Failure of a linear Voussoir arch: a laboratory and numerical study

1992 ◽  
Vol 29 (2) ◽  
pp. 188-194 ◽  
Author(s):  
B. Stimpson ◽  
M. Ahmed
Keyword(s):  
Numerical Study ◽  
Progressive Failure ◽  
Load Capacity ◽  
Failure Process ◽  
Physical Models ◽  
Ultimate Load Capacity ◽  
Element Analysis ◽  
Underground Openings ◽  
Physical Model Tests ◽  
Discrete Crack

The design of underground openings in horizontally layered strata on the basis of classical linear arching theory assumes the ultimate load capacity of the roof is limited by crushing or compressional failure at the centre of the arch or at the abutments. In this study, physical model tests on limestone, granite, and potash beams revealed a progressive failure mechanism dominated by discrete tensile fracturing, a quite different failure process to that assumed by classical theory. Subsequently, discrete crack propagation finite element analysis successfully simulated the failure mechanisms observed in the physical models. Key words : rock mechanics, underground design, roof stability, Voussoir arch, fracture.

scholarly journals Numerical Behaviour of Composite K-Joints Subjected to Combined Loading and Corrosive Environment

2018 ◽  
Author(s):  
Chao Hou ◽  
Shameer Saleh ◽  
Lin-Hai Han ◽  
You-Xing Hua
Keyword(s):  
Failure Modes ◽  
Full Range ◽  
Steel Tube ◽  
Combined Loading ◽  
Truss Structures ◽  
Mechanism Analysis ◽  
Corrosive Environment ◽  
Range Analysis ◽  
Element Analysis ◽  
Fea Model

Concrete filled steel tubular (CFST) truss structures have been adopted in various infrastructures worldwide for past several decades. Application of CFST truss is more prevalent especially in areas where harsh marine condition with chloride corrosion limits the design life of structures. Design of joints is one of the most complicated issues in CFST truss structures; and it becomes more critical when corrosion causes section loss in the outer steel tube. Improved designs in terms of economy and durability need to be suggested based on rational research on composite K-joints in corrosive environment, whilst such research is very limited up until now. This paper thus attempts to study the behaviour of circular concrete filled steel tubular (CFST) K-joints under combined effect of long-term loading and corrosion. A finite element analysis (FEA) model is presented and verified against existing test results. The model is then utilized to perform mechanism analysis of CFST K-joints under varying loading and corrosion situations. Failure modes, detailed propagation of yield and stress distribution between the core concrete in chord and the tubular steel is investigated, based on which a favourable mode of failure is suggested in terms of maximum joint capacity. Finally, a full range analysis of the load-deformation characteristics is carried out for various corrosion situations, with the corresponding joint strength as well as ductility predicted.

Progressive failure analysis for the interaction of interlaminar and intralaminar failure modes in composite structures with an initial delamination

2013 ◽  
Vol 117 (1187) ◽  
pp. 71-85 ◽  
Author(s):  
W. Ji ◽  
A. M. Waas
Keyword(s):  
Failure Analysis ◽  
Composite Laminates ◽  
Composite Structures ◽  
Failure Modes ◽  
Progressive Failure ◽  
Laminated Composite ◽  
Composite Panel ◽  
Analysis Tool ◽  
Plane Failure ◽  
Progressive Failure Analysis

AbstractThis paper is concerned with the development of a failure initiation and progressive failure analysis (PFA) method for advanced composite structures. The present PFA model is capable of predicting interactive out-of-plane and in-plane failure modes observed in fiber reinforced composite laminates including interlaminar behavior and matrix microdamage at the mesoscale. A probability analysis tool is coupled with the PFA to account for uncertainty in modelling parameters caused by material variability and manufacturing inconsistencies. The progressive damage response of a laminated composite panel with an initial delamination is studied and used to demonstrate the PFA modelling framework that is presented here.

Failure Analysis of Laminate on Influence of the Hole

2012 ◽  
Vol 450-451 ◽  
pp. 590-593
Author(s):  
Yin Huan Yang
Keyword(s):  
Failure Analysis ◽  
Composite Structures ◽  
Parametric Design ◽  
Numerical Study ◽  
Laminated Composites ◽  
Progressive Failure ◽  
Failure Process ◽  
Laminated Composite ◽  
Progressive Failure Analysis ◽  
Ultimate Failure

Failure process of laminated composites is performed by progressive failure analysis method. A modified form of Hashin’s failure criterion by Shokrieh is used to investigate the failure, where a sudden degradation model is proposed to reduce engineering material constants. The numerical study of laminated composites is implemented in ANSYS Parametric Design Language (APDL). The initiation and propagation of local damage and response of laminated composite structures from initial loading and ultimate failure are predicted. The model has been validated by comparing numerical results with existing experimental results. And then failure analysis of specimen fabricated from M40J/Ag80 on influence of the hole has been performed by the proposed model.

Mechanical Behaviour of Alloy 800 Steam Generator Tube With a Circumferential Crack-Like Throughwall Flaw

2011 ◽  
Author(s):  
Congyue Wang ◽  
Xinjian Duan ◽  
Mukesh Jain
Keyword(s):  
Steam Generator ◽  
Mechanical Behaviour ◽  
Numerical Study ◽  
Strain Curve ◽  
Image Correlation ◽  
Element Analysis ◽  
Fea Model ◽  
Alloy 800 ◽  
Circumferential Crack ◽  
Tension Tests

This paper presents an experimental and numerical study of the mechanical behaviour of Alloy 800 tubes with a circumferential crack-like throughwall flaw. The crack-like throughwall flaw was simulated as a slot fabricated by Electron Discharge Machining (EDM). A digital image correlation (DIC) method is employed to measure the distribution of strain and the deformed EDM slot profile during the tension test. A Finite Element Analysis (FEA) model in ANSYS is then developed to predict the mechanical behaviour of Alloy 800 steam generator (SG) tubing in the tension tests. The FEA model with a verified material stress-strain curve and the calibrated failure criterion is applied to simulate the burst test of SG tubing with a circumferential crack-like throughwall flaw. The maximum allowable size for a circumferential throughwall crack is recommended based on FEA simulations.

scholarly journals Effect of Sheets’ Thickness and Rivet Geometry on Mechanical Properties of Orbital Riveted Aluminium Joints: Experimental and Numerical Analysis

2021 ◽  
Vol 5 (4) ◽  
pp. 102
Author(s):  
Guido Di Bella ◽  
Luigi Calabrese ◽  
Chiara Borsellino ◽  
Tiziana Alderucci
Keyword(s):  
Mechanical Properties ◽  
Failure Modes ◽  
Numerical Study ◽  
Sheet Thickness ◽  
Mechanical Resistance ◽  
Joint Geometry ◽  
Riveted Joints ◽  
Low Load ◽  
Relative Stress ◽  
Tension Fracture

Orbital riveting is an innovative joining technology used in various industrial fields. Despite its diffusion in recent years, it has not been accompanied by an equivalent interest from the scientific community, which has neglected the aspects of process optimization and joint performance. In this experimental/numerical study, six different configurations of orbital riveted joints were realised and tested to determine the effects of sheet thickness and rivet geometry on the mechanical properties of the joints and their failure modes. The results showed that the configuration of the joint significantly affects both its resistance and fracture mechanism. Moreover, it was possible to identify a transition between different failure modes by changing the rivet diameter. A non-optimal joint geometry favours a premature fracture at very low load (i.e., S9A21 batch with net tension fracture). The highest mechanical resistance was found in the S8A15 batch, which experienced unbuttoning failure. In order to better correlate the joint geometry with the mechanical behaviour and the relative stress distribution, a simplified numerical FEM was validated with the experimental results.

scholarly journals Experimental Analysis of Riveted and Hybrid Joints for Composite Structures using Finite Element Analysis

2021 ◽  
pp. 311-336
Author(s):  
Mr. Prasad Shirvalkar ◽  
Prof. Ashish H. Raut
Keyword(s):  
Glass Fibre ◽  
Composite Laminates ◽  
Composite Structures ◽  
Hybrid Composites ◽  
Testing Machine ◽  
Von Mises Stress ◽  
Full Potential ◽  
Engineering Applications ◽  
Element Analysis ◽  
Hybrid Joints

Composites have been used extensively in various engineering applications including automotive, aerospace, and building industries. Hybrid composites made from two or more different reinforcements show enhanced mechanical properties required for advanced engineering applications. Modeling, static analysis of 3D models and Manufacturing of the composite joints (bonded, riveted and hybrid) were carried out using FEA software. The results were interpreted in terms of Von Mises stress. To utilize the full potential of composite materials like Glass Fibre - epoxy as structural elements, the strength and stress distribution of these joints namely, bonded, riveted and hybrid joints must be understood while conducting experimental works. Various joints like bonded, riveted and hybrid joints were prepared by glass fibre epoxy composite laminates. And then undergo a tensile test by a universal testing machine with a data acquisition system. The results will then be compared with the joints. The Best Joint is identified by their load Bearing Capacity.

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