A Hybrid Supervised Deep Learning and Nonlinear Finite Element Framework for Efficient Fatigue Life Predictions of Rotary Shouldered Threaded Connections

2021 ◽  
Author(s):  
Fei Song ◽  
Ke Li
Keyword(s):  
Finite Element ◽  
Deep Learning ◽  
Fatigue Life ◽  
Nonlinear Finite Element ◽  
Threaded Connections ◽  
Life Predictions

A Hybrid Supervised Deep Learning and Nonlinear Finite Element Framework for Efficient Fatigue Life Predictions of Rotary Shouldered Threaded Connections

2020 ◽  
Author(s):  
Fei Song ◽  
Ke Li
Keyword(s):  
Finite Element ◽  
Deep Learning ◽  
Fatigue Life ◽  
Learning Algorithm ◽  
Fatigue Tests ◽  
Full Scale ◽  
Remaining Useful Life ◽  
Nonlinear Finite Element ◽  
Threaded Connections ◽  
Life Predictions

Abstract In this paper, a hybrid computational framework that combines the state-of-the art machine learning algorithm (i.e., deep neural network) and nonlinear finite element analysis for efficient and accurate fatigue life prediction of rotary shouldered threaded connections is presented. Specifically, a large set of simulation data from nonlinear FEA, along with a small set of experimental data from full-scale fatigue tests, constitutes the dataset required for training and testing of a fast-loop predictive model that could cover most commonly used rotary shouldered connections. Feature engineering was first performed to explore the compressed feature space to be used to represent the data. An ensemble deep learning algorithm was then developed to learn the underlying pattern, and hyperparameter tuning techniques were employed to select the learning model that provides the best mapping, between the features and the fatigue strength of the connections. The resulting fatigue life predictions were found to agree favorably well with the experimental results from full-scale bending fatigue tests and field operational data. This newly developed hybrid modeling framework paves a new way to realtime predicting the remaining useful life of rotary shouldered threaded connections for prognostic health management of the drilling equipment.

Nonlinear Finite Element Analysis of a Threaded Pipe Connection

2004 ◽  
Author(s):  
Farzad Tasbihgoo ◽  
John P. Caffrey ◽  
Sami F. Masri
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Experimental Tests ◽  
Element Model ◽  
Nonlinear Finite Element ◽  
Mitigation Measures ◽  
Element Analysis ◽  
Nonstructural Components ◽  
Small Water ◽  
Threaded Connections

For the past several years, USC has been involved in a major research project to study the seismic mitigation measures of nonstructural components in hospitals funded by the Federal Emergency Management Agency (FEMA). It was determined that piping was the one of the most critical components affecting the functionality of a hospital following an earthquake. Consequently, a substantial effort was spent on quantifying the behavior of typical piping components. During the loading of the threaded joint, it was common to hear a loud popping sound, followed by a small water leak. It was assumed that the sound and leakage were due to the sliding of the mating pipe threads. To confirm this theory, and to provide a tool to help understand the failure mode(s) for a wide class of threaded fittings, a detailed nonlinear finite element model was constructed using MSC/NASTRAN, and correlated to the measured failures. In this paper, a simplified model is presented first to demonstrate the modeling procedure and to help understand the sliding phenomenon. Next, a symmetric half 3D model was generated for modeling the physical experiments. It is shown that the finite element analysis (FEA) of the threaded connections captures the dominant mechanism that was observed in the experimental tests.

Fatigue Life Predictions by Coupling Finite Element and Multibody Systems Calculations

1997 ◽  
Author(s):  
Stefan Dietz ◽  
Helmuth Netter ◽  
Delf Sachau
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Elastic Body ◽  
Multibody Systems ◽  
Life Prediction ◽  
Fatigue Life Prediction ◽  
Dynamic Loads ◽  
Multibody Simulation ◽  
Bogie Frame ◽  
Life Predictions

Abstract The dynamic loads and accelerations acting on a railway bogie are predicted by multibody simulation. The bogie frame is considered as an elastic body of the MBS-model, in which elastic displacements are represented by eigen and staticmodes. Stresses are calculated for the most stressed locations of a bogie in the MBS-postprocessor. Based on these a fatigue life prediction is carried out.

Comparison of Two Axisymmetric Finite Element Models of Threaded Connections

1999 ◽  
Author(s):  
Mark Hommel
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Tensile Load ◽  
Bending Moment ◽  
Element Analysis ◽  
Axisymmetric Loading ◽  
Axisymmetric Model ◽  
Threaded Connection ◽  
Threaded Connections ◽  
Run Time

Abstract Predicting the fatigue life of threaded connections using finite element analysis generally requires a 2-D axisymmetric model capable of handling non-axisymmetric loading in order to simulate an applied bending moment. This is desirable from the standpoint of computer run time, as compared with the alternative approach, namely, developing a full 3-D model. Unfortunately, due to their esoteric nature, the 2-D axisymmetric elements with non-axisymmetric loading capability are not supported by the software vendors as well as the other elements, hence pre- and post-processing are more challenging. In addition, due to the Fourier representation of the non-axisymmetric load, computer run time and storage is increased significantly over that of a strictly 2-D axisymmetric model. In view of this, common practice has been to use instead the conventional axisymmetric model with an equivalent applied axial tensile stress equal to the mean bending stress through the wall thickness in order to simulate the bending moment and thereby avoid the necessity for non-axisymmetric loading. The question therefore arises as to how well the results from the strictly axisymmetric model agree with the results from the axisymmetric model with non-axisymmetric loading capability. The purpose of this paper is to compare the results of the two models. A 5-1/2 F.H. threaded connection is modeled by means of a commercial finite element code. First, the axisymmetric model with non-axisymmetric loading capability is treated and results are obtained. Second, the axisymmetric model with applied equivalent tensile load is examined and its results are compared with the former model. It is found that the value of the primary variable of interest for quantification of fatigue life, namely, alternating stress, agrees between the two models within 4%. Thus, it is concluded that the simplified model provides a viable alternative for modeling fatigue life of threaded connections.

Thermomechanical Analysis of Solder Joints Under Thermal and Vibrational Loading

2001 ◽  
Vol 124 (1) ◽  
pp. 60-66 ◽  
Author(s):  
Cemal Basaran ◽  
Rumpa Chandaroy
Keyword(s):  
Finite Element ◽  
Fatigue Life ◽  
Solder Joint ◽  
Constitutive Model ◽  
Solder Joints ◽  
Cycle Fatigue ◽  
Simultaneous Application ◽  
Short Cycle ◽  
Finite Element Procedure ◽  
Life Predictions

Due to the coefficient of thermal expansion (CTE) mismatch between the bonded layers, the solder joint experiences cycling shear strain, which leads to short cycle fatigue. When semiconductor devices are used in a vibrating environment, additional strains shorten the fatigue life of a solder joint. Reliability of these joints in new packages is determined by laboratory tests. In order to use the FEM to replace these expensive reliability tests a unified constitutive model for Pb40/Sn60 solder joints has been developed and implemented in a thermo-viscoplastic-dynamic finite element procedure. The model incorporates thermal-elastic-viscoplastic and damage capabilities in a unified manner. The constitutive model has been verified extensively against laboratory test data. The finite element procedure was used for coupled thermo-viscoplastic-dynamic analyses for fatigue life predictions. The results indicate that using Miner’s rule to calculate accumulative damage by means of two separate analyses, namely dynamic and thermo-mechanical, significantly underestimates the accumulative total damage. It is also shown that a simultaneous application of thermal and dynamic loads significantly shortens the fatigue life of the solder joint. In the microelectronic packaging industry it is common practice to ignore the contribution of vibrations to short cycle fatigue life predictions. The results of this study indicate that damage induced in the solder joints by vibrations have to be included in fatigue life predictions to accurately estimate their reliability.

Load Distribution Between Threads in Threaded Connections

1997 ◽  
Vol 119 (1) ◽  
pp. 91-95 ◽  
Author(s):  
A. S. Grewal ◽  
M. Sabbaghian
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Pressure Vessel ◽  
Load Distribution ◽  
Axial Load ◽  
Three Dimensional ◽  
Nonlinear Finite Element ◽  
Finite Element Code ◽  
Finite Element Analyses ◽  
Threaded Connections

Threaded connections are commonly employed in axial load-bearing equipment and pressure vessel components. There are a number of parameters that affect the load distribution between the threads and the stress concentration at the thread roots. These include the thread form, the thickness of walls supporting the threads, the pitch of threads, number of threads engaged, and the boundary conditions. In this paper, the influence of these parameters on the load distribution between threads is reported. Load distribution analyses in threaded connections is performed by analytical and by finite element methods. Square and buttress-type threads have been considered. Three-dimensional nonlinear finite element analyses on threaded connections have been performed using MSC/NASTRAN finite element code. The effect of clearance between the nonmating faces of threads as well as the presence of a flexible media between the mating faces of threads are investigated.

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