scholarly journals Comparative manufacture and testing of induction- welded and adhesively bonded carbon fibre PEEK stiffened panels

2018 ◽  
Vol 32 (12) ◽  
pp. 1622-1649 ◽  
Author(s):  
M Flanagan ◽  
A Doyle ◽  
K Doyle ◽  
M Ward ◽  
M Bizeul ◽  
...  
Keyword(s):  
Carbon Fibre ◽  
Compressive Loading ◽  
Welding Process ◽  
Stiffened Panel ◽  
Adhesively Bonded ◽  
Load Bearing Capacity ◽  
Stiffened Panels ◽  
Automotive Components ◽  
Assembly Technique ◽  
Continuous Induction

This work presents details of manufacturing and testing of a carbon fibre polyetheretherketone induction-welded hat-stiffened panel. Mechanical testing is carried out to evaluate the performance of the welded assembly and results are compared with similar testing of an adhesively bonded panel. The results show that the welded panel and the bonded panel had similar load-bearing capacity (<2% difference) and stiffness (<1% difference). Optical microscopy is used to verify the weld quality and identify manufacturing artefacts associated with induction welding. Inspection of the panel after welding shows that the induction welding process caused minor warpage, voids and delamination in the panel. The work addresses the lack of data relating to demonstrator scale welded assemblies in the literature, demonstrates that continuous induction welding is a suitable assembly technique for aerospace and automotive components under uniaxial in-plane compressive loading and identifies process-induced artefacts that may occur during induction welding.

Design, analysis, and manufacturing of a carbon-fibre-reinforced polyetheretherketone slat

2009 ◽  
Vol 223 (8) ◽  
pp. 1115-1123 ◽  
Author(s):  
R Keck ◽  
W Machunze ◽  
W Dudenhausen ◽  
P Middendorf
Keyword(s):  
Carbon Fibre ◽  
High Velocity ◽  
Numerical Optimization ◽  
Low Cost ◽  
Welding Process ◽  
Numerical Approach ◽  
Thermoplastic Composite ◽  
Assembly Technique ◽  
Manufacturing Techniques ◽  
Impact Simulations

Regarding aircrafts, the application of composites within impact endangered areas is unusual. Therefore, an advanced thermoplastic composite slat had been developed with the aim of minimizing weight and manufacturing costs in scheduled series production. The investigation of many manufacturing techniques had been performed as well as integration of new materials. Several generic and full-scale thermoplastic demonstrators were manufactured, using endless fibre-reinforced carbon-fibre-reinforced polyetheretherketone tapes. The critical point, concerning the casting of thick and highly tapered, single curved thermoplastic shells, was identified and new manufacturing methods had been developed. Additionally, the thermoplastic welding process was improved, resulting in a low-cost assembly technique as an alternative to state-of-the-art joining methods. In addition to conventional linear static analysis, dynamic high-velocity impact simulations were carried out. A numerical approach for high-velocity bird strike impact had been developed. The results were used to dimension the residual strength of a damaged slat. Furthermore, a good compliance between the dynamic analysis and the performed tests has been reached. It has been shown that a significant weight reduction is possible by numerical optimization, even if composites are used for impact-sensitive areas.

Influence of Model Geometry and Boundary Conditions on the Ultimate Strength of Stiffened Panels Under Uniaxial Compressive Loading

2012 ◽  
Author(s):  
Mingcai Xu ◽  
Masahiko Fujikubo ◽  
C. Guedes Soares
Keyword(s):  
Boundary Conditions ◽  
Ultimate Strength ◽  
Geometric Model ◽  
Compressive Loading ◽  
Fe Analysis ◽  
Stiffened Panel ◽  
Stiffened Panels ◽  
Collapse Mode ◽  
Strain Relationship ◽  
Model Geometry

The aim of this paper is to find out an appropriate configuration of boundary conditions and geometric model to calculate the ultimate strength of a continuous stiffened panel under uniaxial compressive loading in FE analysis. The 1+1 bays model with periodical symmetric boundary conditions is proposed to be used in FE analysis, whose results are compared with 1/2+1+1/2 bays model with periodical symmetric and symmetric boundary conditions, and 1/2+1+1+1/2 bays model with symmetric boundary conditions. The effects of the continuity of the stiffened panel with different geometric models and boundary conditions on its collapse mode are investigated. A beam tension test has been used to define the true stress-strain relationship.

Analysis of Residual Stress Effect on Fatigue Crack Propagation in Bonded Aeronautical Stiffened Panels

2011 ◽  
Vol 681 ◽  
pp. 236-242 ◽  
Author(s):  
Ivan Meneghin ◽  
Goran Ivetic ◽  
Enrico Troiani
Keyword(s):  
Residual Stress ◽  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Stress Fields ◽  
Stiffened Panel ◽  
Stress Effect ◽  
Adhesively Bonded ◽  
Stiffened Panels ◽  
Residual Stress Effect

The application of adhesively bonded straps made of high-static strength materials on aeronautical stiffened panels to retard the fatigue skin crack growth is currently a topical research subject. The detrimental effect of the residual stress fields induced as a consequence of the dissimilar coefficients of thermal expansion of the skin and strap materials on the fatigue skin crack propagation was investigated. The residual stresses induced in a stiffened panel representative of a pressurized fuselage shell with titanium doublers in the middle of the stringer bays is numerically quantified for two likely operational temperatures. Their effect on the fatigue crack propagation is analyzed by means of a linear elastic fracture mechanics approach. The results show that adhesively bonded straps on the cracked surface can significantly retard the fatigue crack propagation but, in order to achieve reliable and conservative predictions on their performances, the effect of the residual stress fields they introduce must be taken into account.

Influence of Model Geometry and Boundary Conditions on the Ultimate Strength of Stiffened Panels Under Uniaxial Compressive Loading

2013 ◽  
Vol 135 (4) ◽  
Author(s):  
Ming Cai Xu ◽  
Masahiko Fujikubo ◽  
C. Guedes Soares
Keyword(s):  
Boundary Conditions ◽  
Ultimate Strength ◽  
Geometric Model ◽  
Compressive Loading ◽  
Fe Analysis ◽  
Stiffened Panel ◽  
Stiffened Panels ◽  
Symmetric Boundary Condition ◽  
Strain Relationship ◽  
Model Geometry

The aim of this paper is to determine an appropriate configuration of the boundary conditions and geometric model to calculate the ultimate strength of a continuous stiffened panel under compressive loading in the finite element (FE) analysis. The 1 + 1 spans model with periodical symmetric boundary conditions is proposed to be used in the FE analysis, whose results are compared with the 1/2 + 1 + 1/2 span model with periodical symmetric and symmetric boundary condition, and the 1/2 + 1 + 1 + 1/2 span model with symmetric boundary conditions. The effects of the continuity of the stiffened panel with different geometric models and boundary conditions on its collapse mode are investigated. A beam tension test has been used to define the true stress-strain relationship in the FE analysis. The two-span model, either 1 + 1 or 1/2 + 1 + 1/2, with periodical symmetric conditions give a reasonable FE modeling, which can consider both odd and even number half waves and, thus, have the smallest model uncertainty.

Qualifications of Adhesives for Marine Composite-to-Steel Bonded Applications

2009 ◽  
Vol 25 (04) ◽  
pp. 198-205
Author(s):  
George W. Ritter ◽  
David R. Speth ◽  
Yu Ping Yang
Keyword(s):  
Mechanical Property ◽  
Structural Integrity ◽  
Adhesively Bonded ◽  
Load Bearing Capacity ◽  
Property Evaluation ◽  
Marine Industry ◽  
Straightforward Method ◽  
Bonded Composite ◽  
Steel Joints ◽  
Marine Composite

This paper describes a straightforward method for the design and certification of adhesively bonded composite to steel joints for the marine industry. Normally, certification is based on documented service at sea. Since these joints have not been previously deployed at sea, no data on their performance exist. Using an integrated combination of mechanical property evaluation and finite element modeling, the load- bearing capacity of a joint can be compared with the anticipated seaway loads. Calculated factors of safety for the sandwich design used here show that the joint has adequate strength to maintain structural integrity even after severe environmental exposure.

scholarly journals Effects of plies orientations and initial geometric imperfections on buckling strength of a composite stiffened panel

2018 ◽  
Vol 191 ◽  
pp. 00008
Author(s):  
Ikram Feddal ◽  
Abdellatif Khamlichi ◽  
Koutaiba Ameziane
Keyword(s):  
Stiffened Panel ◽  
Buckling Mode ◽  
Element Analysis ◽  
Geometric Imperfections ◽  
Stiffened Panels ◽  
Specific Strength ◽  
Euler Buckling ◽  
Buckling Behavior ◽  
Composite Stiffened Panel ◽  
Strength And Stiffness

The use of composite stiffened panels is common in several activities such as aerospace, marine and civil engineering. The biggest advantage of the composite materials is their high specific strength and stiffness ratios, coupled with weight reduction compared to conventional materials. However, any structural system may reach its limit and buckle under extreme circumstances by a progressive local failure of components. Moreover, stiffened panels are usually assembled from elementary parts. This affects the geometric as well as the material properties resulting in a considerable sensitivity to buckling phenomenon. In this work, the buckling behavior of a composite stiffened panel made from carbon Epoxy Prepregs is studied by using the finite element analysis under Abaqus software package. Different plies orientations sets were considered. The initial distributed geometric imperfections were modeled by means of the first Euler buckling mode. The nonlinear Riks method of analysis provided by Abaqus was applied. This method enables to predict more consistently unstable geometrically nonlinear induced collapse of a structure by detecting potential limit points during the loading history. It was found that plies orientations of the composite and the presence of geometric imperfections have huge influence on the strength resistance.

scholarly journals The Prediction of Buckling Load of Laminated Composite Hat-Stiffened Panels Under Compressive Loading by Using of Neural Networks

2018 ◽  
Vol 12 (1) ◽  
pp. 468-480 ◽  
Author(s):  
Shashi Kumar ◽  
Rajesh Kumar ◽  
Sasankasekhar Mandal ◽  
Atul K. Rahul
Keyword(s):  
Neural Network ◽  
Finite Element ◽  
Network Architecture ◽  
Laminated Composite ◽  
Buckling Load ◽  
Stiffened Panel ◽  
Stiffness Ratio ◽  
Data Set ◽  
Stiffened Panels ◽  
Structural Problems

Background:Stiffened panels are being used as a lightweight structure in aerospace, marine engineering and retrofitting of building and bridge structure. In this paper, two efficient analytical computational tools, namely, Finite Element Analysis (FEA) and Artificial Neural Network (ANN) are used to analyze and compare the results of the laminated composite 750-hat-stiffened panels.Objective:Finite Element (FE) is an efficient and versatile method for the analysis of a complex problem. FE models have been used to generate data set of four different parameters. The four parameters are extensional stiffness ratio of skin in the longitudinal direction to the transverse direction, orthotropy ratio of the panel, the ratio of twisting stiffness to transverse flexural stiffness and smeared extensional stiffness ratio of stiffeners to that of the plate.Results and Conclusion:For training of ANN, multilayer feedforward back-propagation has been used as a network function with two-hidden layers in the neural network. The good network architecture is achieved after several iterations to predict the buckling load of the stiffened panel. ANN prediction for unknown new data set is in good agreement with FEA results of different cases, which show that ANN tool can be used for the design of complex structural problems in civil engineering and optimization of the laminated composite stiffened panel.

scholarly journals Multi-configuration Stiffened Panels under Compressive Load: Part 1 – Theoretical Analysis

2018 ◽  
Vol 7 (3.11) ◽  
pp. 38
Author(s):  
Ramzyzan Ramly ◽  
Wahyu Kuntjoro ◽  
Amir Radzi Abdul Ghani ◽  
Rizal Effendy Mohd Nasir ◽  
Zulkifli Muhammad
Keyword(s):  
Theoretical Analysis ◽  
Experimental Analysis ◽  
Critical Loads ◽  
Input Parameter ◽  
Compressive Loading ◽  
Compressive Load ◽  
Cross Sectional ◽  
Stiffened Panels ◽  
Compression Load ◽  
Main Input

Stiffened panels are the structure used in the aircraft wing skin panels. Stiffened panels are often critical in compression load due to its thin structural configuration. This paper analyzes the critical loads of a multi configuration stiffened panels under axial compressive loading. The study comprised three main sections; theoretical analysis, numerical analysis and experimental analysis. The present paper deals only with the theoretical analysis. This first part of analysis is very important since the results will be the main input parameter for the subsequent numerical and experimental analysis. The analysis was done on the buckling properties of the panels. Four panel configurations were investigated. Results showed that even though the stiffened panels have the same cross-sectional area, their critical loads were not identical.   

scholarly journals Comparative study of welding deformation of a stiffened panel under various welding procedures

2017 ◽  
Vol 233 (1) ◽  
pp. 182-191 ◽  
Author(s):  
Zhen Chen ◽  
Qi Yu ◽  
Yu Luo ◽  
R Ajit Shenoi
Keyword(s):  
Large Scale ◽  
Welding Process ◽  
Production Quality ◽  
Welding Distortion ◽  
Stiffened Panel ◽  
Welding Deformation ◽  
Large Scale Structures ◽  
Improve Production Quality ◽  
Scale Structures ◽  
Welding Procedure

The welding distortions of large-scale structures are extraordinary complicated. If an effective tool of predicting welding distortion is available, then marine design and manufacturing engineers can use this to improve production quality and reduce costs. This article focuses on the comparative studies of welding procedure of a stiffened panel. An efficient thermal elasto-plastic finite element method–based procedure is developed to predict the welding deformation and residual stress of structures. A combined shell/solid model is adopted to enhance modeling and calculation efficiency. The welding process of a stiffened panel is simulated. Three welding procedures of simultaneous, successive and bidirectional welding are studied. The results show that welding distortion can be well controlled by adjusting the welding procedure.

Finite Element Analysis of Top-Hat–Stiffened Panels of Fiber-Reinforced–Plastic Boat Structures

2007 ◽  
Vol 44 (01) ◽  
pp. 16-26
Author(s):  
Ömer Eksik ◽  
R. Ajit Shenoi ◽  
Stuart S. J. Moy ◽  
Han Koo Jeong
Keyword(s):  
Finite Element ◽  
Lateral Pressure ◽  
Three Dimensional ◽  
Element Model ◽  
Stiffened Panel ◽  
Element Analysis ◽  
Stiffened Panels ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic ◽  
Experimental Findings

This paper describes the development of a finite element model in order to assess the static response of a top-hat-stiffened panel under uniform lateral pressure. Systematic calculations were performed for deflection, strain, and stress using the developed model based on the ANSYS three-dimensional solid element (SOLID45). The numerical modeling results were compared to the experimental findings for validation and to further understand an internal stress pattern within the different constituents of the panel for explaining the likely causes of the panel failure. Good correlation between experimental and numerical strains and displacements was achieved.

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