Modeling the Effect of Material Behavior and Mild Thermal Treatments on Collapse Resistance of UOE Pipes

2012 ◽  
Author(s):  
Santiago Serebrinsky ◽  
Luciano Mantovano ◽  
Marcos de Souza ◽  
Martín Valdez ◽  
Hugo Ernst ◽  
...  
Keyword(s):  
Flow Stress ◽  
Thermal Cycling ◽  
Accurate Determination ◽  
Large Diameter ◽  
Primary Objective ◽  
Material Behavior ◽  
Brazilian Coast ◽  
Main Concern ◽  
Thermal Treatments ◽  
Element Analysis

Oil exploration and production of offshore sources is continuously shifting towards increasing depths and more severe environmental conditions. Ultra deep waters are an objective in, e.g., the pre-salt layer off the Brazilian coast and in the Gulf of Mexico. Under these conditions, resistance to collapse of pipelines is a main concern. Increasing the collapse pressure pc is thus a primary objective, which would lead to a reduction of material and installation costs. To increase pc, it is fundamental to understand which variables affect it, and how to control these variables. For instance, it is well known that ovality, residual stresses, and material constitutive behavior have a direct effect on pc. Current efforts for improving pc of large diameter UOE pipes include an increase in flow stress by the application of a thermal cycle, similar to those typical of coating processes. These thermal treatments recover at least part of the early yielding due to the Bauschinger effect that develops during the collapse test, after the expansion stage. Predictive modeling of pc, based on an appropriate set of input variables, allows for an adequate design of deep- and ultra-deep water projects. In the present work, an assessment by finite element analysis of the requirements on material characterization tests for a reliable prediction of pc has been performed. The most appropriate testing direction is the transverse compression. Moreover, since for large diameter pipes the plastic strain levels attained at collapse are often below 0.2%, the sample should allow for an accurate determination of compression behavior in this very low deformation range. This is particularly relevant for cold-formed pipes, as with the UOE process. Based on these guidelines, a testing sample geometry and compression data processing methodology has been designed. The methodology has been applied to a series of UOE processed pipes that had been thermally treated. On one hand, compression samples were extracted and used for the FE calculation of pc. On the other hand, collapse tests were performed on the same pipes. Both the absolute values of pc, and the enhancement of pc due to thermal cycling, were accurately predicted. In addition, both the flow stress after thermal cycling, and the measured pc values, clearly show that the fabrication factor αfab used in the standard DNV OS-F101 should be set to αfab≥1 for an adequate rating of the pipes.

Hybrid Analytical and Experimental Method for Characterization of Thin Multilayer Bonded Structures Subject to Thermal Loading

2018 ◽  
Author(s):  
Alireza Shirazi ◽  
Hua Lu ◽  
Ahmad Varvani
Keyword(s):  
Thermal Cycling ◽  
Material Properties ◽  
Accurate Determination ◽  
High Accuracy ◽  
Thin Layers ◽  
Material Behavior ◽  
Interfacial Stress ◽  
Bonding Layer ◽  
Global Deformation ◽  
Warpage Deformation

This study is presenting a non-local closed-form solution for interfacial stress/strain and the warpage deformation for thin trilayer plate structures under thermal cycling. Based on the theory of geometric scale dependency of the material behavior, the material properties of a thin multi-layer inter-bonded structures substantially differ from those determined based on the bulk material samples. Hence the real mechanical properties for such thin layers are often unavailable and difficult to obtain. This paper puts forward a method to provide a solution for thermomechanical behavior of trilayer constituents with high accuracy at real scale. Present study demonstrates that the constitutive behavior of multilayer plate’s constituents can be inversely determined so long as the plate’s global deformation can be made available by measurement. To achieve most accurate determination of the material properties, measurements with high accuracy is required. The paper also presents the advanced method of shadow moiré that have applied to obtain warpage deformation of real life trilayer test specimens under thermal cycling. Using this method, the experimentally determined global deformation (warpage) of a trilayer structure were correlated with the analytical model solved for warpage deformation. The correlation was then progressively optimized to result in material properties of the constituents. The bonding layer properties are called determined, once the correlation reaches over 85%. There exist a variety of different multilayer bonded structures, which are usually made with advanced manufacturing processes. Regardless of design layout and materials constitutive relations, the application can be implemented in characterizing multiply stacked trilayer structures.

Testing Extrusion Flow Stress and Friction Factor via Inverse Analysis

2011 ◽  
Vol 381 ◽  
pp. 128-134
Author(s):  
Xin Ping Dai ◽  
Yun Ni
Keyword(s):  
Finite Element ◽  
Flow Stress ◽  
Friction Factor ◽  
Inverse Analysis ◽  
Accurate Determination ◽  
Material Strength ◽  
Strain Hardening Exponent ◽  
Element Analysis ◽  
Pure Lead ◽  
Simulation And Experiment

Accurate determination of flow stress and friction factor is the guarantee of accuracy for finite element analysis of metal extrusion. Firstly, flow stress equation parameters for materials test were initially decided in order to perform finite element analogy. Then, the simulation values and experiment values were compared and the iterative optimization algorithm was used to amend the parameters. The objective was that value error of simulation and experiment values was controlled within tolerance. Finally, accurate flow stress and friction factor were determined. In rod-rod composite extrusion experiment of pure lead,it is determined by inverse analysis that the material strength coefficient is 11.9, strain hardening exponent is 0.127,and friction factor is 0.18. The comparison of the load-stroke curve between simulation and experiment and pure lead upsetting test contribute to confirm that the measured data is accurate. The results show that inverse analysis is a precise, simple and practical method for measuring flow stress and friction factor.

Scratch Tip Radius Effects on K-Controlled Slow Crack Growth in PE Pipe

2008 ◽  
Author(s):  
Carlos R. Corleto ◽  
Brian B. Cole
Keyword(s):  
Finite Element ◽  
Crack Growth ◽  
Slow Crack Growth ◽  
Large Diameter ◽  
Material Behavior ◽  
Element Analysis ◽  
Pipe Model ◽  
Industry Practice ◽  
Notch Tip ◽  
Tip Radius

A study to evaluate the effect of scratch tip radius on stress intensity factor (K) controlled slow crack growth (SCG) was performed to establish whether a plastics pipe industry practice to allow scratches 10% the thickness of the pipe, could still be allowed on large diameter pipes with blunt scratches. A series of finite element analyses were done using a 1/4 two-dimensional (2-D) notched pipe model assuming a 12-in diameter pipe with a standard dimentional ratio (SDR) of 11, a notch ten times smaller than its thickness, notch tip ratios ranging from 16 to 0.0459, and linear elastic material behavior. Results indicate K-controlled SCG would occur if the ratio of notch tip radius to notch depth is less than 0.1667, although this ratio is probably very conservative due to scratch tip blunting from the formation of a craze zone ahead of crack tips in polyethylene (PE) pipes. However, for ratios greater than 0.5, ductile failures could be induced for internal pressures yielding high hoop stresses and at high temperatures. This is due to the fact that stress concentration factors for relatively blunt notches can still induce maximum scratch tip stresses several times higher than the hoop stress of an unscratched pipe. The results of this finite element analysis could be validated experimentally using ASTM D2837-01 following notching procedures given in ISO 13479 with modified cutters to obtain several notch tip radii.

Material Testing for the Prediction of the Effect of Deformation and Aging Thermal Treatments on Collapse Resistance of UOE Pipes

2013 ◽  
Author(s):  
Santiago Serebrinsky ◽  
Luciano Mantovano ◽  
Fábio Arroyo ◽  
Martín Valdez ◽  
Hugo Ernst ◽  
...  
Keyword(s):  
Plastic Material ◽  
Accurate Determination ◽  
Large Diameter ◽  
Testing Procedure ◽  
Material Behavior ◽  
Collapse Pressure ◽  
Factors Affecting ◽  
Exploration And Production ◽  
Input Variables ◽  
Large Diameter Pipes

Oil & Gas offshore exploration and production increase continuously in deep waters. This trend requires pipes with increasing collapse pressure (pc), which is the primary design variable. The prediction of pc, based on an appropriate set of input variables, allows for the appropriate design of deep and ultra-deep water projects. Elastic and plastic material behavior is one of the main factors affecting pc. International application codes (e.g., DNV OS-F101) incorporate the yield strength into their formulas for pc. In the present work, an assessment of the requirements on material characterization tests for a reliable prediction of pc has been performed. The most appropriate testing direction is the transverse compression. Moreover, since for large diameter pipes the plastic strain levels attained at collapse are often below 0.2%, the sample should allow for an accurate determination of compression behavior in this very low deformation range. This is particularly relevant for cold-formed pipes, as with the UOE process. Based on these guidelines, a testing procedure has been designed. This analysis has been applied to the prediction of the effect of thermal cycles on pc. Calculated values show a very good agreement with experimental pc values determined for a series of UOE processed pipes that had been thermally treated and collapsed.

scholarly journals Impact of residual stress evoked by pyramidal embossing on the magnetic material properties of non-oriented electrical steel

2021 ◽  
Author(s):  
Ines Gilch ◽  
Tobias Neuwirth ◽  
Benedikt Schauerte ◽  
Nora Leuning ◽  
Simon Sebold ◽  
...  
Keyword(s):  
Magnetic Material ◽  
Residual Stress ◽  
Magnetic Flux ◽  
Material Properties ◽  
Electrical Steel ◽  
Maximum Energy ◽  
Material Behavior ◽  
Electrical Machine ◽  
Element Analysis ◽  
Steel Sheets

AbstractTargeted magnetic flux guidance in the rotor cross section of rotational electrical machines is crucial for the machine’s efficiency. Cutouts in the electrical steel sheets are integrated in the rotor sheets for magnetic flux guidance. These cutouts create thin structures in the rotor sheets which limit the maximum achievable rotational speed under centrifugal forces and the maximum energy density of the rotating electrical machine. In this paper, embossing-induced residual stress, employing the magneto-mechanical Villari effect, is studied as an innovative and alternative flux barrier design with negligible mechanical material deterioration. The overall objective is to replace cutouts by embossings, increasing the mechanical strength of the rotor. The identification of suitable embossing geometries, distributions and methodologies for the local introduction of residual stress is a major challenge. This paper examines finely distributed pyramidal embossings and their effect on the magnetic material behavior. The study is based on simulation and measurements of specimen with a single line of twenty embossing points performed with different punch forces. The magnetic material behavior is analyzed using neutron grating interferometry and a single sheet tester. Numerical examinations using finite element analysis and microhardness measurements provide a more detailed understanding of the interaction of residual stress distribution and magnetic material properties. The results reveal that residual stress induced by embossing affects magnetic material properties. Process parameters can be applied to adjust the magnetic material deterioration and the effect of magnetic flux guidance.

A Highly Accelerated Thermal Cycling (HATC) Test for Solder Reliability Assessment in BGA Packages

2007 ◽  
Author(s):  
X. Long ◽  
I. Dutta ◽  
R. Guduru ◽  
R. Prasanna ◽  
M. Pacheco
Keyword(s):  
Thermal Cycling ◽  
Solder Joints ◽  
Low Cycle Fatigue ◽  
Inelastic Strain ◽  
Fatigue Reliability ◽  
Element Analysis ◽  
Mechanical Cycling ◽  
Experimental Apparatus ◽  
Dependent Strain ◽  
Accelerated Thermal Cycling

A thermo-mechanical loading system, which can superimpose a temperature and location dependent strain on solder joints, is proposed in order to conduct highly accelerated thermal-mechanical cycling (HATC) tests to assess thermal fatigue reliability of Ball Grid Array (BGA) solder joints in microelectronics packages. The application of this temperature and position dependent strain produces generally similar loading modes (shear and tension) encountered by BGA solder joints during service, but substantially enhances the inelastic strain accumulated during thermal cycling over the same temperature range as conventional ATC (accelerated thermal cycling) tests, thereby leading to a substantial acceleration of low-cycle fatigue damage. Finite element analysis was conducted to aid the design of experimental apparatus and to predict the fatigue life of solder joints in HATC testing. Detailed analysis of the loading locations required to produce failure at the appropriate joint (next to the die-edge ball) under the appropriate tension/shear stress partition are presented. The simulations showed that the proposed HATC test constitutes a valid methodology for further accelerating conventional ATC tests. An experimental apparatus, capable of applying the requisite loads to a BGA package was constructed, and experiments were conducted under both HATC and ATC conditions. It is shown that HATC proffers much reduced cycling times compared to ATC.

Role of Out-of-Plane Coefficient of Thermal Expansion in Electronic Packaging Modeling

1999 ◽  
Vol 122 (2) ◽  
pp. 121-127 ◽  
Author(s):  
Manjula N. Variyam ◽  
Weidong Xie ◽  
Suresh K. Sitaraman
Keyword(s):  
Thermal Expansion ◽  
Electronic Packaging ◽  
Thermal Loading ◽  
Coefficient Of Thermal Expansion ◽  
Plane Deformation ◽  
Three Dimensional ◽  
Dissimilar Materials ◽  
3D Models ◽  
Material Behavior ◽  
Element Analysis

Components in electronic packaging structures are of different dimensions and are made of dissimilar materials that typically have time, temperature, and direction-dependent thermo-mechanical properties. Due to the complexity in geometry, material behavior, and thermal loading patterns, finite-element analysis (FEA) is often used to study the thermo-mechanical behavior of electronic packaging structures. For computational reasons, researchers often use two-dimensional (2D) models instead of three-dimensional (3D) models. Although 2D models are computationally efficient, they could provide misleading results, particularly under thermal loading. The focus of this paper is to compare the results from various 2D, 3D, and generalized plane-deformation strip models and recommend a suitable modeling procedure. Particular emphasis is placed to understand how the third-direction coefficient of thermal expansion (CTE) influences the warpage and the stress results predicted by 2D models under thermal loading. It is seen that the generalized plane-deformation strip models are the best compromise between the 2D and 3D models. Suitable analytical formulations have also been developed to corroborate the findings from the study. [S1043-7398(00)01402-X]

scholarly journals Failure Mechanisms of Cu–Cu Bumps under Thermal Cycling

Materials ◽  
2021 ◽  
Vol 14 (19) ◽  
pp. 5522
Author(s):  
Kai-Cheng Shie ◽  
Po-Ning Hsu ◽  
Yu-Jin Li ◽  
Dinh-Phuc Tran ◽  
Chih Chen
Keyword(s):  
Thermal Cycling ◽  
Grain Boundaries ◽  
Maximum Stress ◽  
Failure Mechanisms ◽  
Deep Understanding ◽  
Bonding Interface ◽  
Triple Junctions ◽  
Element Analysis ◽  
Resistance Change ◽  
Hybrid Joints

The failure mechanisms of Cu–Cu bumps under thermal cycling test (TCT) were investigated. The resistance change of Cu–Cu bumps in chip corners was less than 20% after 1000 thermal cycles. Many cracks were found at the center of the bonding interface, assumed to be a result of weak grain boundaries. Finite element analysis (FEA) was performed to simulate the stress distribution under thermal cycling. The results show that the maximum stress was located close to the Cu redistribution lines (RDLs). With the TiW adhesion layer between the Cu–Cu bumps and RDLs, the bonding strength was strong enough to sustain the thermal stress. Additionally, the middle of the Cu–Cu bumps was subjected to tension. Some triple junctions with zig-zag grain boundaries after TCT were observed. From the pre-existing tiny voids at the bonding interface, cracks might initiate and propagate along the weak bonding interface. In order to avoid such failures, a postannealing bonding process was adopted to completely eliminate the bonding interface of Cu–Cu bumps. This study delivers a deep understanding of the thermal cycling reliability of Cu–Cu hybrid joints.

scholarly journals Numerical Simulation Analysis of Combined Seismic Response for Rock-Lining-Water in Hydraulic Tunnel

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Guoqing Liu ◽  
Yanhong Zhang ◽  
Ming Xiao
Keyword(s):  
Numerical Simulation ◽  
Seismic Response ◽  
Simulation Analysis ◽  
Large Diameter ◽  
Water Diversion ◽  
Seismic Stability ◽  
Central Difference ◽  
Element Analysis ◽  
Internal Water ◽  
Lining Structure

In order to explore the influence of internal water on the seismic response of hydraulic tunnel, the combined mechanical analysis models of multimaterial including surrounding rock, lining structure, and internal water are built. Based on the explicit central difference method, the dynamic finite element analysis methods for rock, lining, and water are discussed, respectively. The dynamic contact force method is used to simulate the rock-lining contact interaction, and the arbitrary Lagrange-Euler (ALE) method is used to simulate the lining-water coupling interaction. Then a numerical simulation analysis method for combined seismic response of rock-lining-water system in hydraulic tunnel is proposed, and the detailed solving steps are given. This method is used to study the seismic stability characteristics of the water diversion tunnel in a hydropower station, and the displacement, stress, and damage failure characteristics of the lining structure under the conditions of no water, static water, and dynamic water are comparatively analyzed. The results show that the hydrostatic pressure restricts the seismic response of the lining, while the hydrodynamic pressure exacerbates its seismic response and leads to damage, separation, and slip failure appearing on the haunch, which can provide a scientific reference for the seismic design of hydraulic tunnel with high water head and large diameter.

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