Alignment Criteria for Through-Wall Flaws in Plates and Pipes

2008 ◽  
Author(s):  
B. Bezensek ◽  
K. Miyazaki
Keyword(s):  
Finite Element ◽  
Load Capacity ◽  
Damage Model ◽  
Fe Model ◽  
Experimental Sample ◽  
Fe Modelling ◽  
Combination Rules ◽  
Single Flaw

Multiple flaws in vessels and pipes are frequently assessed as a larger single flaw in accordance with the flaw alignment and combination rules. In this paper the alignment of two through-wall flaws is examined for plates in tension and pipes in bending using detailed finite element (FE) modelling. The FE model is developed using the Gurson-Tvergaard damage model and accurately describes the flaw interaction and load capacity of a random experimental sample. Results suggests that two flaws should be aligned onto the same plane for the purpose of assessment when the separation between the parallel planes containing flaws equals the flaw length for both, plates in tension and pipes in bending.

Representation of bolted joints in a structure using finite element modelling and model updating

2020 ◽  
Vol 14 (3) ◽  
pp. 7141-7151 ◽  
Author(s):  
R. Omar ◽  
M. N. Abdul Rani ◽  
M. A. Yunus
Keyword(s):  
Finite Element ◽  
Dynamic Behaviour ◽  
Model Updating ◽  
Complex Structure ◽  
Bolted Joints ◽  
Model Parameters ◽  
Fe Model ◽  
Bolted Joint ◽  
Fe Modelling ◽  
Joint Structure

Efficient and accurate finite element (FE) modelling of bolted joints is essential for increasing confidence in the investigation of structural vibrations. However, modelling of bolted joints for the investigation is often found to be very challenging. This paper proposes an appropriate FE representation of bolted joints for the prediction of the dynamic behaviour of a bolted joint structure. Two different FE models of the bolted joint structure with two different FE element connectors, which are CBEAM and CBUSH, representing the bolted joints are developed. Modal updating is used to correlate the two FE models with the experimental model. The dynamic behaviour of the two FE models is compared with experimental modal analysis to evaluate and determine the most appropriate FE model of the bolted joint structure. The comparison reveals that the CBUSH element connectors based FE model has a greater capability in representing the bolted joints with 86 percent accuracy and greater efficiency in updating the model parameters. The proposed modelling technique will be useful in the modelling of a complex structure with a large number of bolted joints.

Finite Element Analysis of Load Capacity on Coupling Clamps for Pipe

2012 ◽  
Vol 201-202 ◽  
pp. 741-744 ◽  
Author(s):  
Zhen Ning Hou ◽  
Jun Wu ◽  
Qing Wang ◽  
Hong Gen Tian ◽  
Nan Chao ◽  
...  
Keyword(s):  
Finite Element ◽  
Stress Intensity ◽  
Optimization Design ◽  
Load Capacity ◽  
Three Dimensional ◽  
Process Conditions ◽  
Fe Model ◽  
Three Dimensional Model ◽  
Element Analysis ◽  
Element Approach

A finite element approach based on Ansys is developed to simulate stress intensity distribution in a three dimensional model of coupling clamp joint, which includes ferrules, pipe caps and bolts. The characteristics of stress intensity distributions of coupling clamp joint under strength pressure loading have been studied by means of the non-linear finite element method. The FE model can also predict the clamp quality and tolerances to be expected under different process conditions and define the most effective process parameters to influence the tolerances. The study could give us a better understanding on the mechanism and basis for optimization design of the coupling clamp joint.

On the Axisymmetric Response of a Damaged Flexible Pipe

2014 ◽  
Author(s):  
José Renato M. de Sousa ◽  
Carlos Magluta ◽  
Ney Roitman ◽  
George C. Campello
Keyword(s):  
Finite Element ◽  
Analytical Model ◽  
Load Capacity ◽  
High Stress ◽  
Experimental Tests ◽  
Theoretical Models ◽  
Experimental Measurements ◽  
Fe Model ◽  
Flexible Pipe ◽  
High Stress Concentration

This work focuses on the structural analysis of a damaged 9.13″ flexible pipe to pure and combined axisymmetric loads. A set of experimental tests was carried out considering one up to ten broken wires in the outer tensile armor of the pipe and the results obtained are compared to those provided by a previously presented finite element (FE) model and a traditional analytical model. In the experimental tests, the pipe was firstly subjected to pure tension and, then, the responses to clockwise and anti-clockwise torsion superimposed with tension were investigated. In these tests, the induced strains in the outer armor were measured. Moreover, the axial elongation of the pipe was monitored when the pipe is subjected to tension, whilst the twist of the pipe was measured when torsion is imposed. The experimental results pointed to a slight decrease in the stiffness of the pipe with the increasing number of broken wires and, furthermore, a redistribution of forces among the intact wires of the damaged layer with high stress concentration in the wires close to the damaged ones. Both theoretical models captured these features, but, while the results obtained with the FE model agreed well with the experimental measurements, the traditional analytical model presented non-conservative results. Finally, the results obtained are employed to estimate the load capacity of the pipe.

NONLINEAR FINITE ELEMENT MODELING OF POST-TENSION RC AND RC BEAMS STRENGTHENED WITH NSM FRP RODS

2020 ◽  
Vol 7 (2) ◽  
Author(s):  
Belal Elharouney ◽  
Ayman Hussein ◽  
Ezz El-Deen Mostafa ◽  
Amr El-Nemr
Keyword(s):  
Finite Element ◽  
Reinforced Concrete ◽  
Concrete Beam ◽  
Load Capacity ◽  
Reinforced Concrete Beam ◽  
Experimental Results ◽  
Fe Model ◽  
Post Tension ◽  
Bending Loading ◽  
Frp Bars

The post-tensioned (PT) reinforced beams can provide a fast construction advantage through precast and cast-in-situ structural elements. However, due to the excessive increase in load capacity, especially when it comes to girder of bridges, the strengthening using Fiber-reinforced polymer (FRP) might be a solution. Near-surface mounted (NSM) is one of the methods used in strengthening cases, especially in the case of non-degraded concrete cover. Furthermore, very few researchers visited this area experimentally, which consider cost-effective. In this paper, two finite element models using the Abaqus program validated experimental results for both Post-tension beam and strengthening of the beam using NSM separately as preliminary models for combining both systems. PT reinforced concrete beam subjected to four-point bending loading as well as reinforced concrete beam strengthened with NSM using FRP bars subjected to two-point bending loading examined and validated through a 3D non-linear finite element (FE) model to be compared by the experimental results. This FE model considered the non-linear constitutive properties of concrete, yielding of steel, and the bond between strand, concrete, and FRP bars at NSM. The models were targeting the strengthening of existing Post tension girder beams of existing bridges structures. These modeling results showed a reasonable agreement with the tested beam results in terms of failure modes, the load capacity, load-deflection curve, and cracking behavior.

Finite element modelling and load share analysis for involute worm gears with localized tooth contact

2001 ◽  
Vol 215 (7) ◽  
pp. 805-816 ◽  
Author(s):  
F Yang ◽  
D Su ◽  
C. R. Gentle
Keyword(s):  
Finite Element ◽  
Load Capacity ◽  
Worm Gear ◽  
Tooth Contact Analysis ◽  
Fe Modelling ◽  
Tooth Contact ◽  
Transmission Errors ◽  
Meshing Stiffness ◽  
Worm Gears ◽  
Gear Drives

A new approach has been developed by the authors to estimate the load share of worm gear drives, and to calculate the instantaneous tooth meshing stiffness and loaded transmission errors. In the approach, the finite element (FE) modelling is based on the modified tooth geometry, which ensures that the worm gear teeth are in localized contact. The geometric modelling method for involute worm gears allows the tooth elastic deformation and tooth root stresses of worm gear drives under different load conditions to be investigated. On the basis of finite element analysis, the instantaneous meshing stiffness and loaded transmission errors are obtained and the load share is predicted. In comparison with existing methods, this approach applies loaded tooth contact analysis and provides more accurate load capacity rating of worm gear drives.

Mechanism of Slow Crack Growth in Polyethylene: A Finite Element Approach

2015 ◽  
Author(s):  
Xiangpeng Luo ◽  
Jianfeng Shi ◽  
Jinyang Zheng
Keyword(s):  
Finite Element ◽  
Crack Growth ◽  
Failure Time ◽  
Bulk Material ◽  
Slow Crack Growth ◽  
Damage Model ◽  
Constitutive Models ◽  
Fe Model ◽  
Notch Angle ◽  
Craze Zone

Slow crack growth (SCG) is a common failure mode in underground polyethylene (PE) piping which was designed for 50-year services. It had been revealed by experiments that the SCG process is caused by continuous propagation of the craze zone at the crack tip through the bulk material. However, the mechanism of SCG failure has not been understood clearly. The eXtended Finite Element Method (XFEM) is found to be an effective tool for locally non-smooth features (voids, cracks, etc.) in solid or fluid mechanics solutions. In this paper the time-dependent property of PE was considered, a viscoelastic constitutive model was used for the bulk material. To represent the material deterioration during SCG, a damage model was developed for the craze zone. Combined with the XFEM, the process of the Pennsylvania Notched Test (PENT), which had been widely applied for characterizing resistance of SCG for PE pipes or resins, was analyzed based on the proposed finite element (FE) model containing the two constitutive models. The numerical results were then compared with the experimental data in literatures. It showed that the failure time and final notch angle were in agreement with the experimental observations. Based on the verified FE model, strain distributions along the boundary of the crack were studied and the shortcomings of this model were discussed.

scholarly journals Finite Element Modelling and Updating of Welded Thin-Walled Beam

2018 ◽  
Vol 15 (4) ◽  
pp. 5874-5889 ◽  
Author(s):  
M. S. M. Fouzi ◽  
K. M. Jelani ◽  
N. A. Nazri ◽  
Mohd Shahrir Mohd Sani
Keyword(s):  
Finite Element ◽  
Model Updating ◽  
Normal Mode Analysis ◽  
Mode Analysis ◽  
Modal Parameters ◽  
Fe Model ◽  
Fe Modelling ◽  
Welded Structure ◽  
Thin Walled ◽  
Fe Model Updating

This article concentrates on the finite element (FE) modelling approach to model welded thin-walled beam and the adoption of model updating technique to enhance the dynamic characteristic of the FE model. Four different types of element connectors which are RBE2, CBAR, CBEAM and CELAS format are used to construct the FE model of welded structure. Normal mode analysis is performed using finite element analysis (FEA) software, MSC Patran/Nastran to extract the modal parameters (natural frequency and mode shape) of the FE model. The precision of predicted modal parameters obtained from the four models of welded structure are compared with the measured counterparts. The dynamic characteristics of a measured counterpart is obtained through experimental modal analysis (EMA) using impact hammer method with roving accelerometer under free-free boundary conditions. In correlation process, the CBAR model has been selected for updating purposes due to its accuracy in prediction with measured counterparts and contains updating parameters compared to the others. Ahead of the updating process, sensitivity analysis is made to select the most sensitive parameter for updating purpose. Optimization algorithm in MSC Nastran is used in FE model updating process. As a result, the discrepancy between EMA and FEA is managed to be reduced. It shows the percentage of error for updated CBAR model shrinks from 7.85 % to 2.07 % when compared with measured counterpart. Hence, it is found that using FE model updating process provides an efficient and systemic way to perform a feasible FE model in replicating the real structure.

scholarly journals Moisture Induced Deformations in Glulam Members - Experiments and 3-D Finite Element Model

2017 ◽  
Vol 36 (2) ◽  
pp. 35-45
Author(s):  
Henry M. Kiwelu
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Solid Wood ◽  
Average Moisture Content ◽  
Fe Model ◽  
Fe Modelling ◽  
Average Value ◽  
Hybrid Buildings ◽  
External Shape

Experiments were performed on scaled glue laminated bending specimens to observetime dependent development of deformations during drying and wetting. Measurementsdetermined changes in the average moisture content and external shape and dimensionsbetween when specimens were placed into constant or variable climates. Alterations inthe external shape and dimensions reflected changes in the average value anddistribution of moisture and mechanosorptive creep in the glulam. The results are beingused to develop a sequentially-coupled three-dimensional hygrothermal Finite Element(FE) model for predicting temporally varying internal strains and external deformationsof drying or wetting solid wood structural components. The model implies temporallyvarying, and eventual steady, state internal stress distributions in members based onelastic and creep compliances that represent wood within glulam as a continuousorthotropic homogenised material. Thus, predictions are consistent with smearedengineering stress analysis methods rather than being a physically correct analogue ofhow solid wood behaves. This paper discusses limitations of and intended improvementsto the FE modelling. Complementary investigations are underway to address otheraspects of the hygrothermal behaviour of structural members of wood and othermaterials (e.g. reinforced concrete) embedded within superstructure frameworks ofmulti-storey hybrid buildings.

scholarly journals NUMERICAL SIMULATION OF THE BLAST-RESISTANT RESPONSE OF ULTRAHIGH-PERFORMANCE CONCRETE STRUCTURAL MEMBERS

2019 ◽  
Vol 25 (6) ◽  
pp. 587-598 ◽  
Author(s):  
Hor Yin ◽  
Kazutaka Shirai ◽  
Wee Teo
Keyword(s):  
Damage Model ◽  
High Strength ◽  
Material Model ◽  
Experimental Results ◽  
Fe Model ◽  
Structural Members ◽  
Fe Modelling ◽  
Constitutive Material Model ◽  
Concrete Damage ◽  
Explicit Solver

This paper presents the blast responses of ultrahigh-performance concrete (UHPC) structural members obtained using finite element (FE) modelling. The FE model was developed using LS-DYNA with an explicit solver. In the FE simulation, the concrete damage model, which is a plasticity-based constitutive material model, was employed for the concrete material. The simulation results were verified against previous experimental results available in the literature and were shown to be in good agreement with the experimental results. In addition, the developed FE model was implemented in a parametric study by varying the blast weight charges. The numerical results for UHPC members were compared with those for conventional reinforced concrete (RC) members. The numerical responses, such as the maximum deflections, deflected shapes, and damage patterns, of the UHPC members subjected to blast loading were significantly better performance than those of the RC members as a result of the high strength and ductile capacity of UHPC.

Structural Response of Timber-Concrete Composite Beams Predicted by Finite Element Models and Manual Calculations

2014 ◽  
Vol 17 (11) ◽  
pp. 1601-1621 ◽  
Author(s):  
Nima Khorsandnia ◽  
Hamid Valipour ◽  
Keith Crews
Keyword(s):  
Finite Element ◽  
Axial Stress ◽  
Damage Model ◽  
Structural Response ◽  
General Purpose ◽  
Finite Element Models ◽  
Fe Model ◽  
Loading Capacity ◽  
Model Predictions ◽  
Ultimate Loading Capacity

This paper presents the structural response of timber-concrete composite (TCC) beams predicted by finite element models (i.e. continuum-based and 1D frame) and manual calculations. Details of constitutive laws adopted for modelling timber and concrete are provided and application of the Hashin damage model in conjunction with continuum-based FE for capturing failure of timber under bi-axial stress state is discussed. A simplified strategy for modelling the TCC connection is proposed in which the connection is modelled by a nonlinear spring and the full load-slip behaviour of each TCC connection is expressed with a formula that can be directly implemented in the general purpose FE codes and used for nonlinear analysis of TCC beams. The developed FE models are verified by examples taken from the literature. Furthermore, the load-displacement response and ultimate loading capacity of the TCC beams are determined according to Eurocode 5 method and compared with FE model predictions.

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