Reelability Assessment of Adhesively Bonded Mechanically Lined Pipe

2021 ◽  
Author(s):  
Grégory Alexandre Toguyeni ◽  
Jens Fernandez-Vega ◽  
Richard Jones ◽  
Martin Gallegillo ◽  
Joachim Banse

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.

2015 ◽  
Vol 1119 ◽  
pp. 828-832
Author(s):  
K. Vadivuchezhian ◽  
K. Subrahmanya ◽  
N. Chockappan

Metal foil strain gauges are most widely used for the stress analysis in engineering structures. Typical strain gauge system includes strain sensitive grid, carrier material, and adhesive layer. Strain measurement from the strain gauge is partially affected by carrier and adhesive materials and their thickness. In the present work, a Finite Element Model is developed in order to study the effect of both adhesive layer and carrier thickness on strain measurements while using strain gauges. To understand the behavior of the adhesive material, mechanical characterization is done on bulk adhesive specimen. Finite Element Analysis (FEA) is carried out with different materials namely epoxy and polyurethane. Initially a single element foil loop is considered for the analysis and further this is extended to metal foil strain gauge with nine end-loops. Finally, the strain variation through thickness of adhesive layer, carrier and strain sensitive grid is obtained from FEA. The results thus obtained are compared with analytical results from Basic Strength of Materials approach.


Author(s):  
Budy Notohardjono ◽  
Shawn Canfield ◽  
Suraush Khambati ◽  
Richard Ecker

Shorter development design schedules and increasingly dense product designs create difficult challenges in predicting structural performance of a mainframe computer’s structure. To meet certain certification benchmarks such as the Telcordia Technologies Generic Requirements GR-63-CORE seismic zone 4 test profile, a physical test is conducted. This test will occur at an external location at the end of design cycle on a fully functional and loaded mainframe system. The ability to accurately predict the structural performance of a mainframe computer early in the design cycle is critical in shortening its development time. This paper discusses an improved method to verify the finite element analysis results predicting the performance of the mainframe computer’s structure long before the physical test is conducted. Sine sweep and random vibration tests were conducted on the frame structure but due to a limitation of the in-house test capability, only a lightly loaded structure can be tested. Evaluating a structure’s modal stiffness is key to achieving good correlation between a finite element (FE) model and the physical system. This is typically achieved by running an implicit modal analysis in a finite element solver and comparing it to the peak frequencies obtained during physical testing using a sine sweep input. However, a linear, implicit analysis has its limitations. Namely, the inability to assess the internal, nonlinear contact between parts. Thus, a linear implicit analysis may be a good approximation for a single body but not accurate when examining an assembly of bodies where the interaction (nonlinear contact) between the bodies is of significance. In the case of a nonlinear assembly of bodies, one cannot effectively correlate between the test and a linear, implicit finite element model. This paper explores a nonlinear, explicit analysis method of evaluating a structure’s modal stiffness by subjecting the finite element model to a vibration waveform and thereafter post processing its resultant acceleration using Fast Fourier Transformation (FFT) to derive the peak frequencies. This result, which takes into account the nonlinear internal contact between the various parts of the assembly, is in line with the way physical test values are obtained. This is an improved method of verification for comparing sine sweep test data and finite element analysis results. The final verification of the finite element model will be a successful physical seismic test. The tests involve extensive sequential, uniaxial earthquake testing in both raised floor and non-raised floor environments in all three directions. Time domain acceleration at the top of the frame structure will be recorded and compared to the finite element model. Matching the frequency content of these accelerations will be proof of the accuracy of the finite element model. Comparative analysis of the physical test and the modeling results will be used to refine the mainframe’s structural elements for improved dynamic response in the final physical certification test.


2013 ◽  
Vol 377 ◽  
pp. 3-7
Author(s):  
Ze Long You ◽  
Xiang Ming Zhang ◽  
Kui Du

An ANSYS-based "volume-spring-plate" three-dimensional finite element model is established in this paper to analyze steel plate with a rectangular hole reinforced by double-side bonding patch, in which the plate is simulated by solid45 8-node 3D element, the adhesive layer is simulated by linear elastic spring element combin14, and the patch is simulated by shell element. Relative intensity, relative stiffness and yield load rising rate of a patched steel plate with regard to parameters, such as the patch length, width, the number of patch layer and ply orientation are studied. The results indicate that composite bonded repair can effectively restore the mechanical properties of the structure and improve the service life.


2016 ◽  
Vol 846 ◽  
pp. 464-469 ◽  
Author(s):  
Abdallah Ghazlan ◽  
Tuan D. Ngo ◽  
Nelson Lam ◽  
Phuong Tran

This paper investigates the behaviour of a bio-inspired finite element composite model (that mimics the structure of nacre, the inner layer of molluscan shells) under blast loading. Nacre, which has attracted the attention of researchers over the past few decades, comprises 95% aragonite, brittle voronoi-like polygonal tablets that are joined by an organic matrix and arranged in a brick and mortar type structure. In this work, the finite element model developed herein was constructed using voronoi diagrams and geometric algorithms capable of automatically generating staggered layers of voronoi-like aluminium tablets bonded together by a vinylester adhesive layer. Many studies have led to the belief that the magnificent toughness of nacre is mainly attributed to the inter-platelet adhesive bonds. Results obtained from the finite element analysis show that this is indeed true, and it is imperative that the adhesive bond exhibits adequate toughness in order to be able to spread damage across the entire composite, thereby delaying localised failure.


2012 ◽  
Vol 204-208 ◽  
pp. 1109-1117
Author(s):  
Hui Peng ◽  
Shu Yu Yu ◽  
Chun Sheng Cai ◽  
Wei Wei Liu

The bonding behavior of CFRP-concrete interface has important influence on the mechanical behavior and the failure mode of the strengthened structure. In this paper, a total of 4 specimens strengthened with CFRP plate were prepared and the double-shear tests were conducted to investigate the mechanical behavior and the failure mode of the CFRP-concrete bonding. During the tests, the on the ultimate bearing capacity and the distribution of the CFRP strains were measured and the influence of bonding lengths and thickness of the epoxy were discussed. According to the test results, the distribution of the CFRP strain along the bonding length shows an exponential decreasing law, and the strain in the vicinity of the loading position was much greater than that at the ends. Based on the test data, the finite element model of the specimens was developed, by using the orthotropic spring elements to simulate the adhesive layer with ANSYS software. The comparison of the analytical results and the experimental results indicates that both results have shown a good agreement.


2000 ◽  
Author(s):  
Iqbal Anwar ◽  
Golam Newaz

Abstract A computational intensive study was performed to assess an efficient way to model adhesively bonded glass fiber reinforced composite joints in automotive applications. Three different finite element modeling techniques had been implemented. First, adhesive was represented by 1D-spring elements. Spring stiffness was calculated from adhesive property. This model is inadequate to assess stresses developed in the adhesive layer directly. So adhesive was modeled with 2D elements for better assessment of state of stress in the adhesive and the substrate. Both the model provide limit load, but crack initiation and failure of the bond can not be captured. The third approach adopted was the nodal failure model. In the nodal failure model, to understand the failure of adhesively bonded joints, bond strength had been specified to the interface nodes of the composite substrate. Combined failure criteria had been used. Cracks propagated and interface debonded when interface stress exceeded the failure limit. Finite element model results compared well with the experimental data. This modeling approach was later adopted for dynamic modeling of adhesively bonded joints, which shows promise.


2012 ◽  
Vol 530 ◽  
pp. 9-13 ◽  
Author(s):  
Xiao Cong He

This paper investigates normal stress distribution of a single-lap adhesively bonded joint under tension using the three-dimensional finite element methods. Five layers of solid elements were used across the adhesive layer thickness in order to obtain an accurate indication of the variation of normal stress. All the numerical results obtained from the finite element analysis show that the spatial distribution of normal stress are similar for different interfaces though the stress values are obviously different. It can also be seen from the results that the left hand region, which is very close to the left free end of the adhesive layer, is subjected to very high stress and the magnitude of the normal stress oscillates in value close to the left end of the adhesive layer.


2002 ◽  
Author(s):  
Samar Teli ◽  
Erol Sancaktar

The stress interference effects adhesively bonded scarf and butt joints were investigated when an additional adhesive layer was incorporated in overall joint design. Finite element models were developed and analyzed to compare interfacial stress states and peak stresses on the double adhesive layer joints with those on the single adhesive layer joints with respect to the scarf angle, adhesive layer separation (ALS) and adhesive modulus. This comparison was done in terms of stress ratio calculated as a ratio of interfacial peak stress on double adhesive layer joint to that an single adhesive layer joint. The tensile task results were correlated with the finite element analysis (FEA) results in terms of load ratio calculated as a ratio of failure load on single adhesive layer joint to that on double adhesive layer joint. Six scarf angles (15°, 30°, 45°, 60°, 75° and 90°), three ALS and adhesives were analyzed for this study.


Author(s):  
Hazel M. Pierson ◽  
Daniel H. Suchora ◽  
Anthony V. Viviano

This paper investigates the problem of a pipe rolling down a transfer skid and becoming permanently dented as it hits the stops at the end of the skid. See Figure 1. The transfer skid stops under consideration had been successfully used in other applications. However, in this application there was an increase in distance between stations connected by the transfer skid. Thus, as the pipe rolled down the skid it built up significant kinetic energy, which needed to be dissipated upon impact with the skid stop. Unfortunately in this case, the skid stops did not always absorb enough energy to ensure integrity of the pipe. Consequently, certain sizes and grades of pipe experienced denting as they would impact the stops. The skid stop and the pipe must absorb the total kinetic energy possessed by the pipe just before impact. The energy absorbing characteristics of both the skid stop and pipe were developed using a static method. For the skid stop a physical test was performed to obtain the contact force versus deflection curve. For the pipe a finite element analysis was conducted to determine the contact force versus deflection curve. In the finite element model the effect of local yielding of the pipe material was incorporated into the analysis. The energy absorbed by each component was estimated as the area under the contact force-deflection curve and for each component the energy absorbed versus contact force curve was developed. Combining these two results gives the total system energy absorbed by both the pipe and skid stop as a function of contact force. This is compared to the total energy in the pipe just before contact to determine the actual maximum contact force and the actual energy absorbed by each component. The energy that could be elastically given back to the system was also obtained from the model. These results were compared to actual field measurements of dent size and pipe rebound height. The comparisons proved the validity of the model.


Author(s):  
А. Г. Гребеников ◽  
И. В. Малков ◽  
В. А. Урбанович ◽  
Н. И. Москаленко ◽  
Д. С. Колодийчик

The analysis of the design and technological features of the tail boom (ТB) of a helicopter made of polymer composite materials (PCM) is carried out.Three structural and technological concepts are distinguished - semi-monocoque (reinforced metal structure), monocoque (three-layer structure) and mesh-type structure. The high weight and economic efficiency of mesh structures is shown, which allows them to be used in aerospace engineering. The physicomechanical characteristics of the network structures are estimated and their uniqueness is shown. The use of mesh structures can reduce the weight of the product by a factor of two or more.The stress-strain state (SSS) of the proposed tail boom design is determined. The analysis of methods for calculating the characteristics of the total SSS of conical mesh shells is carried out. The design of the tail boom is presented, the design diagram of the tail boom of the transport category rotorcraft is developed. A finite element model was created using the Siemens NX 7.5 system. The calculation of the stress-strain state (SSS) of the HC of the helicopter was carried out on the basis of the developed structural scheme using the Advanced Simulation module of the Siemens NX 7.5 system. The main zones of probable fatigue failure of tail booms are determined. Finite Element Analysis (FEA) provides a theoretical basis for design decisions.Shown is the effect of the type of technological process selected for the production of the tail boom on the strength of the HB structure. The stability of the characteristics of the PCM tail boom largely depends on the extent to which its design is suitable for the use of mechanized and automated production processes.A method for the manufacture of a helicopter tail boom from PCM by the automated winding method is proposed. A variant of computer modeling of the tail boom of a mesh structure made of PCM is shown.The automated winding technology can be recommended for implementation in the design of the composite tail boom of the Mi-2 and Mi-8 helicopters.


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