Simplified stiffness analysis for degraded single lap joints in the space sector – Comparative analytical and finite element analysis

2020 ◽  
Vol 234 (13) ◽  
pp. 1956-1966
Author(s):  
Jannik Zimmermann ◽  
Josef Weiland ◽  
Mohammad Zamaan Sadeghi ◽  
Alexander Schiebahn ◽  
Uwe Reisgen ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Ionizing Radiation ◽  
Coefficient Of Thermal Expansion ◽  
Closed Form Solution ◽  
Adhesive Layer ◽  
Lap Joints ◽  
Polymer Chains ◽  
Adhesively Bonded ◽  
European Organization

Considering the aerospace sector, the use of adhesively bonded joints is constantly increasing over the last decades. Due to its lightweight and capability of joining various materials with different coefficient of thermal expansion, this joining technique offers many benefits over conventional methods like rivets, screws and welding. On the other hand, structural adhesives consists of polymer chains that can be severely affected by the environment. An example of such an environmental effect is the interaction of the polymer chains of the adhesive with ionizing radiation in space. Nevertheless in the literature, the influence of ionizing radiation on the mechanical properties of epoxides is covered but not well understood. The present work describes a method of determining the stiffness of an adhesively bonded single lap joint (SLJ) using closed form solution equations. This analytical approach is compared with a numerical model. The mechanical properties of the adhesive in both models is degraded due to irradiation, based on experiments conducted by the European Organization for Nuclear Research (CERN). The results show that the degradation of the mechanical properties of the adhesive layer has a significant influence on the joint stiffness. This effect increases with growing adhesive layer thickness. Comparing the results with a finite element model, it is shown that the developed calculation scheme overestimates the stiffness of the SLJ. This is caused by the neglection of bending stresses within the adherends.

Effect of Adhesive Layer’s Voids on Stress Distribution of Adhesively Bonded Joints

2010 ◽  
Vol 139-141 ◽  
pp. 986-989 ◽  
Author(s):  
Hai Long Zhao ◽  
Zong Zhan Gao ◽  
Zhu Feng Yue ◽  
Zhi Feng Jiang
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Stress Distribution ◽  
Adhesive Layer ◽  
Shear Loading ◽  
Lap Joints ◽  
Bonded Joints ◽  
Adhesively Bonded ◽  
Adhesively Bonded Joints ◽  
Single Lap Joints

The stress distribution of adhesively-bonded single lap joints under tensile shear loading is analyzed using 2-dimensional elastic-plastic finite element method (FEM). Special attentions have been put on the influence of void in adhesive on the stress distribution of adhesively-bonded joints. The results show that the stress concentration of the void is less than that of the end part of the joints when adhesive layer’s deformation was in the range of elastic. Moreover, the influence of the void on the stress distribution becomes less when the void moving from the end-part to the middle. The stress concentration becomes larger and the stress distribution of adhesive’s mid-thickness region becomes flatter when adhesive layer has biggish plastic deformation. Finite element results show an agreement with the theoretical results.

Reelability Assessment of Adhesively Bonded Mechanically Lined Pipe

2021 ◽  
Author(s):  
Grégory Alexandre Toguyeni ◽  
Jens Fernandez-Vega ◽  
Richard Jones ◽  
Martin Gallegillo ◽  
Joachim Banse
Keyword(s):  
Finite Element ◽  
Adhesive Layer ◽  
Element Model ◽  
Curing Temperature ◽  
Sensitivity Analyses ◽  
Adhesively Bonded ◽  
Element Analysis ◽  
Physical Test ◽  
Weld Overlay ◽  
Outer Pipe

Abstract A solution to prevent liner wrinkling in Mechanically Lined Pipes (MLP) with a standard 3.0mm thick liner during reeling, without the use of pressurisation, has been developed in the form of the GluBi® lined pipe. The liner being adhesively bonded to the outer pipe, its integrity is maintained despite the global plastic strain applied by the installation method. This new linepipe product has been qualified for offshore use through testing accompanied by a detailed Finite Element Analysis programme to fully capture the pipe and adhesive behaviours under and range of temperatures and loading conditions. The objective of this analysis program was to investigate the reelability of the GluBi® pipe. The instalability was defined as the capability of the pipe to tolerate cyclic plastic deformation representative of a typical pipeline installation by reeling without the formation of wrinkling of the CRA liner, and to maintain the integrity of the adhesive layer, particularly near the weld overlay at the pipe ends. Important areas of the GluBi® pipe design are the pipe extremities, particularly the transition between the liner and the weld overlay length. A detailed Finite Element model of the pipe was created. It captured all stages of the pipe manufacturing: pipe lining, hydrostatic expansion, adhesive curing, overlay weld deposition and reeling simulation. The pipe modelled was 312.1mm OD × 19.7mm WT SMLS 450 with a nominal 3.0mm thick Alloy 625 liner. An important validation work was performed to obtain a precise material response of the adhesive layer between liner and outer pipe. The adhesive mechanical properties were thus assessed in shearing and peeling over a range of temperatures covering all possible manufacturing and installation conditions. The model's elements and adhesive property modelling were validated against physical test results. Sensitivity analyses were done on the adhesive curing temperature, the geometry of the adhesive transition between the liner and the overlay weld at the pipe ends and on the liner thickness. The model was subjected to reeling simulation corresponding to Subsea 7's reel-lay vessels. The liner's integrity post reeling was assessed according to a range of acceptance criteria. These studies made it possible to establish parameter ranges for the safe installation of the linepipe.

scholarly journals Compression Shear Properties of Adhesively Bonded Single-Lap Joints of C/C Composite Materials at High Temperatures

Symmetry ◽  
2019 ◽  
Vol 11 (12) ◽  
pp. 1437 ◽  
Author(s):  
Yanfeng Zhang ◽  
Zhengong Zhou ◽  
Zhiyong Tan
Keyword(s):  
Composite Materials ◽  
Adhesive Layer ◽  
Lap Joints ◽  
Experimental Result ◽  
Shear Stresses ◽  
Test Results ◽  
Adhesively Bonded ◽  
Finite Element Software ◽  
Joint Structure ◽  
Simulation Results

The performance of joint structure is an important aspect of composite material design. In this study, we examined the compression shear bearing capacity of the adhesively bonded single-lap joint structure of high-temperature-resistant composite materials (C/C composite materials). The test pieces were produced in accordance with the appropriate ASTM C1292 standard, which were used for the compression shear test. The failure morphology of the layer was observed by a digital microscopic system and scanning electron microscope. The experimental result shows that the load on the test piece increased nonlinearly until the failure occurred, and most of the adhesive layer exhibited cohesive failures at three temperature points (400, 600, and 800 °C), while the interface failures occurred in a small part of the adhesive layer. A numerical analysis model was established using ABAQUS finite element software. The simulation results were compared with the test results to verify the correctness of the model. On the basis of correctness of the model verified by comparing the simulation results and the test results, the influences of temperature and overlapped length on the joint compression shear performance were studied through the validated simulation method. Numerical results showed that the ultimate load of the joint decreased with increases in temperature and that the distribution trends of the shear stresses in the overlapped length direction were substantially the same for joints of different overlapped lengths.

scholarly journals Mechanical Performance Evaluation of the Al-Mg-Si-(Cu) Aluminum Alloys after Transient Thermal Shock through an Novel Equivalent Structure Design and Finite Element Modeling

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 537
Author(s):  
Congchang Xu ◽  
Ke Liu ◽  
Hong He ◽  
Hanlin Xiang ◽  
Xinxin Zhang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Finite Element ◽  
Thermal Shock ◽  
Constitutive Relation ◽  
Mechanical Performance ◽  
Lap Joints ◽  
Structure Design ◽  
Equivalent Structure ◽  
Material Constitutive Relation ◽  
Transient Thermal

In this paper, the microstructure evolution and mechanical performance of the Al-Mg-Si-(Cu) aluminum alloy after transient thermal shock were investigated through experimental tests and finite element simulations. A novel equivalent structure was designed as a typical case in which one side of the plate was welded therefore the other side was thermally shocked with different temperature distribution and duration. The temperature gradient which influences most importantly the mechanical properties was simulated and experimentally verified. Through cutting layers and tensile testing, the mechanical response and material constitutive relation were obtained for each layer. Gurson-Tvergaard-Needlemen (GTN) damage parameters of these samples under large strains were then obtained by the Swift law inverse analysis approach. By sorting the whole welded joint into multi-material composed structure and introducing the obtained material constitutive relation and damage parameters, tensile properties were precisely predicted for typical types of weld joint such as butt, corner, and lap joints. The results show that precipitate coarsening, phase transformation from β″ phase to Q′ phase, and dissolving in the temperature range of 243.3–466.3 °C during the thermal shock induced a serious deterioration of the mechanical properties. The highest reduction of the ultimate tensile strength (UTS) and yield strength (YS) would be 38.6% and 57.4% respectively. By comparing the simulated and experimentally obtained force-displacement curves, the error for the above prediction method was evaluated to be less than 8.1%, indicating the proposed method being effective and reliable.

Effect of Adhesive Layer Thickness on the Shear Strength of Adhesively Bonded Steel Joints in Wet Environment

2016 ◽  
Vol 836 ◽  
pp. 78-82 ◽  
Author(s):  
Sugiman ◽  
Ilham Akbar ◽  
Emmy Dyah Sulistyowati ◽  
Paryanto Dwi Setyawan
Keyword(s):  
Mechanical Properties ◽  
Shear Strength ◽  
Adhesive Layer ◽  
Static Strength ◽  
Adhesive Joints ◽  
Deionized Water ◽  
Adhesively Bonded ◽  
Moist Environment ◽  
Adhesive Thickness ◽  
Steel Joints

The paper presents the static strength of adhesively bonded steel joints aged in deionized water at a temperature of 60°C for 15 days at various adhesive thicknesses from 0.1 mm to 0.5 mm. Water uptake and the bulk adhesive tensile properties after aged in the same environment as the joints were also presented. It has been shown that water diffusion into the adhesive is non Fickian. The absorbed water in the adhesive significantly decreases the mechanical properties and it affects the static strength of the bonded steel joints. The effect of water is shown to be significant when the adhesive thickness is thicker than 0.2 mm as the static strength decreases sharply. This information is useful when designing the adhesive joints using thick adhesive layer exposed in moist environment.

Stress Analysis of Bonded Joint Using Solid Element Combinations

2013 ◽  
Vol 467 ◽  
pp. 332-337
Author(s):  
Xiao Cong He
Keyword(s):  
Finite Element ◽  
Mechanical Behaviour ◽  
Adhesive Layer ◽  
Smooth Transition ◽  
Triangular Prism ◽  
Suitable Model ◽  
Bonded Joints ◽  
Adhesively Bonded ◽  
Adhesively Bonded Joints ◽  
Bonded Joint

This paper describes some finite element combinations to analyse the mechanical behaviour of bonded joints. In finite element models five layers of solid elements were used across the adhesive layer in order to increase the accuracy of the results. The finite elements were refined gradually in steps from adherends to adhesive layer. In these models, most of the adherends and adhesive were modeled using solid brick elements but some solid triangular prism elements were used for a smooth transition. Comparisons are performed between different types of first-order element combinations in order to find a suitable model to predict the mechanical behaviour of adhesively bonded joints.

Sign in / Sign up

Export Citation Format

Share Document