Materials, Fabrication, Installation, and Applied Mechanics Considerations in the Catastrophic Failure of a Flex Hose Bellows

2007 ◽  
Author(s):  
Dennis C. Deegan ◽  
Dennis K. Williams
Keyword(s):  
Selection Process ◽  
Piping System ◽  
Catastrophic Failure ◽  
Applied Mechanics ◽  
Shells Of Revolution ◽  
Flexible Hose ◽  
Element Analysis ◽  
Column Buckling ◽  
Column Type ◽  
Ultimate Failure

This paper is the third in a series that describes the materials, fabrication, installation, and applied mechanics considerations surrounding the catastrophic failure of a bellows component within a metallic flexible hose. The subject flexible hose was utilized in a compressor piping system attachment juncture to a petro-chemical piping system designed in accordance with the ASME B31.3 Process Piping Code. Specifically, the ultimate failure mode issues related to the instability of the metal u-shaped bellows, from which the hose derives its overall flexibility and name, are reviewed and discussed in detail. In an effort to provide a comprehensive examination of the use of the flexible hose in the petrochemical industry, a discussion of the materials, fabrication methods, installation, and, applied mechanics associated with column buckling of the bellows (also known as “squirm”) are presented. A metallurgical failure analysis is presented to identify and document the mode of failure and metallurgical condition of the wire braid and bellows components of the hose. In addition, material examination results, including the discovery of inherent flaws from the fabrication process, are presented and the significance of the findings is presented. The selection process for this particular type of flexible hose (and bellows component) for eventual installation in a vibratory service environment is reviewed in light of the published recommendations provided by the rules of the Expansion Joint Manufacturers Association Standards (EJMA) with regard to squirm are also reviewed and discussed. Finally, a summary of the elastic-plastic finite element analysis of the u-shaped bellows is briefly described and compared against previously published theoretical works on the instability of shells of revolution and most specifically, toroids. The results of the theoretical, empirical, and analytical forensic investigations into the squirm phenomenon are utilized to identify some very practical recommendations in an effort to minimize the probability of catastrophic failures of u-shaped bellows from column type instability.

Catastrophic Failure of Flex Hose Bellows Due to Lateral Offset and Internal Pressure

2007 ◽  
Author(s):  
Dennis K. Williams
Keyword(s):  
Finite Element ◽  
Internal Pressure ◽  
Catastrophic Failure ◽  
Shells Of Revolution ◽  
Flexible Hose ◽  
Element Analysis ◽  
Column Buckling ◽  
Column Type ◽  
The Subject ◽  
Lateral Offset

This paper describes the analytical and empirical analyses conducted in the catastrophic failure of a flexible hose utilized in a petro-chemical environment. Specifically, the issues associated with the instability of the metal u-shaped bellows, from which the hose derives its overall flexibility and name, are reviewed and discussed in detail. In an effort to provide a comprehensive examination of the flexible hose’s use in the petro-chemical industry, a discussion of the applied mechanics associated with column buckling of the bellows (also known as “squirm”) is presented. In addition, the fabrication details that also proved detrimental to the structural adequacy of the subject flexible hose are highlighted. Results from an elastic-plastic finite element analysis of the u-shaped bellows are described and compared against previously published theoretical works on the instability of shells of revolution and most specifically, toroids. The applied loads in the finite element analyses include both internal pressure and transverse displacements (i.e., lateral offset). Furthermore, the guidance provided by the rules of the Expansion Joint Manufacturers Association Standards (EJMA) with regard to squirm are also reviewed and discussed. Finally, the results of the theoretical, empirical, and analytical investigations into the squirm phenomenon are utilized to identify some very practical solutions and recommendations to avoid the possibility of catastrophic failure of u-shaped bellows from column type instability.

Buckling Considerations for U-Shaped Bellows Utilized in Flexible Metal Hoses

2005 ◽  
Author(s):  
Dennis K. Williams
Keyword(s):  
Finite Element ◽  
Longitudinal Axis ◽  
Applied Mechanics ◽  
Finite Element Analyses ◽  
Shells Of Revolution ◽  
Element Analysis ◽  
Column Buckling ◽  
Column Type ◽  
Comprehensive Examination ◽  
Flexible Metal

This paper describes some of the considerations for evaluating the structural adequacy of flexible metal hoses utilized in a petro-chemical or process type environment. Specifically, the issues associated with the instability of the metal U-shaped bellows, from which the hose derives its overall flexibility and name, are reviewed and discussed in detail. In an effort to provide a comprehensive examination of the flexible hose’s use in the petro-chemical industry, a discussion of the applied mechanics associated with both column buckling of the bellows (also known as “squirm”) and in-plane buckling is presented. Results from a non-linear column buckling finite element analysis (FEA) of the U-shaped bellows are described and compared against previously published theoretical works on the instability of shells of revolution and most specifically, toroids. The applied loads in the finite element analyses include both internal pressure and transverse displacements (i.e., translations perpendicular to the longitudinal axis of the hose/bellows assembly). In addition, the guidance provided by the rules of the Expansion Joint Manufacturers Association Standards (EJMA) with regard to squirm are also reviewed and discussed. Finally, the results of both the theoretical and analytical investigations into the squirm phenomenon are utilized to identify some very practical solutions and recommendations to avoid the possibility of catastrophic failure of U-shaped bellows from column type instability.

Study and Analysis of MEMS Pressure Sensor Based on Applied Mechanics

2013 ◽  
Vol 771 ◽  
pp. 159-162
Author(s):  
Li Feng Qi ◽  
Zhi Min Liu ◽  
Xing Ye Xu ◽  
Guan Zhong Chen ◽  
Xue Qing
Keyword(s):  
Finite Element Analysis ◽  
Pressure Sensor ◽  
High Sensitivity ◽  
Scientific Basis ◽  
Sensor Chip ◽  
Applied Mechanics ◽  
Beam Structure ◽  
Element Analysis ◽  
Sensor Development ◽  
Piezoresistive Pressure Sensor

The relative research of low range and high anti-overload piezoresistive pressure sensor is carried out in this paper and a new kind of sensor chip structure, the double ends-four beam structure, is proposed. Trough the analysis, the sensor chip structure designed in this paper has high sensitivity and linearity. The chip structure is specially suit for the micro-pressure sensor. The theoretical analysis and finite element analysis is taken in this paper, which provide important scientific basis for the pressure sensor development.

Pipeline Dent Management Program

2002 ◽  
Author(s):  
Scott D. Ironside ◽  
L. Blair Carroll
Keyword(s):  
Finite Element ◽  
Oil And Gas ◽  
Selection Process ◽  
Element Model ◽  
Field Trials ◽  
Management Program ◽  
Operating Conditions ◽  
Published Data ◽  
Element Analysis ◽  
The Past

Enbridge Pipelines Inc. operates the world’s longest and most complex liquids pipeline network. As part of Enbridge’s Integrity Management Program In-Line Inspections have been and will continue to be conducted on more than 15,000 km of pipeline. The Inspection Programs have included using the most technologically advanced geometry tools in the world to detect geometrical discontinuities such as ovality, dents, and buckles. During the past number of years, Enbridge Pipelines Inc. has been involved in developing a method of evaluating the suitability of dents in pipelines for continued service. The majority of the work involved the development of a method of modeling the stresses within a dent using Finite Element Analysis (FEA). The development and validation of this model was completed by Fleet Technology Limited (FTL) through several projects sponsored by Enbridge, which included field trials and comparisons to previously published data. This model combined with proven fracture mechanics theory provides a method of determining a predicted life of a dent based on either the past or future operating conditions of the pipeline. CSA Standard Z662 – Oil and Gas Pipeline Systems provides criteria for the acceptability of dents for continued service. There have been occurrences, however, where dents that meet the CSA acceptability criteria have experienced failure. The dent model is being used to help define shape characteristics in addition to dent depth, the only shape factor considered by CSA, which contribute to dent failure. The dent model has also been utilized to validate the accuracy of current In-Line Inspection techniques. Typically a dent will lose some of its shape as the overburden is lifted from the pipeline and after the indentor is removed. Often there can be a dramatic “re-rounding” that will occur. The work included comparing the re-rounded dent shapes from a Finite Element model simulating the removal of the constraint on the pipe to the measured dent profile from a mold of the dent taken in the field after it has been excavated. This provided a measure of the accuracy of the tool. This paper will provide an overview of Enbridge’s dent management program, a description of the dent selection process for the excavation program, and a detailed review of the ILI validation work.

Creep Life Simulation and Assessment of High Temperature Piping Systems and Components

2012 ◽  
Author(s):  
Brian Rose ◽  
James Widrig
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
High Temperature ◽  
Creep Behavior ◽  
Material Behavior ◽  
Piping System ◽  
Remaining Life ◽  
Creep Life ◽  
Element Analysis ◽  
Piping Systems

High temperature piping systems and associated components, elbows and bellows in particular, are vulnerable to damage from creep. The creep behavior of the system is simulated using finite element analysis (FEA). Material behavior and damage is characterized using the MPC Omega law, which captures creep embrittlement. Elbow elements provide rapid yet accurate modeling of pinching of piping, which consumes a major portion of the creep life. The simulation is used to estimate the remaining life of the piping system, evaluate the adequacy of existing bellows and spring can supports and explore remediation options.

Finite Element Analysis for the Evaluation of Cracks at a Pipe-Flange Welded Part by the Direct-Current Potential Difference Method

2015 ◽  
Author(s):  
Naoya Tada ◽  
Masaki Kosaka
Keyword(s):  
Finite Element ◽  
Direct Current ◽  
Difference Method ◽  
Evaluation Method ◽  
Fatigue Cracking ◽  
Potential Difference ◽  
Piping System ◽  
Element Analysis ◽  
Non Destructive ◽  
Current Potential

The use of a flange joint is a popular method to close the end of pipes or connect pipes in manufacturing industries. As the pipes are often subjected to vibrations and cyclic bending, fatigue cracking may occur at the welded part between the pipe and flange. It is therefore important to detect and monitor the cracking in this part to ensure safety of the whole piping system. The direct-current potential difference method (DC-PDM) is known as a suitable non-destructive technique to monitor the initiation and growth of cracks and it has been applied to cracks and wall thinning on the inner surface of pipes. In this study, finite element analyses were carried out to clarify the relationship between the size and location of cracks at the pipe-flange welded part and the potential difference. An evaluation method of circumferential crack length angle by DC-PDM was proposed.

scholarly journals Material selection and design analysis of multi-purpose disposable safety syringe

2018 ◽  
Vol 7 (4.13) ◽  
pp. 214-220
Author(s):  
Mohd Nasri Ishak ◽  
Abd Rahim Abu Talib ◽  
Mohammad Yazdi Harmin
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Material Selection ◽  
Selection Process ◽  
Design Analysis ◽  
Element Analysis ◽  
Safety Feature ◽  
The Finite Element Analysis ◽  
Current Design ◽  
Selection For

Current design of safety syringes requires two handed operation and additional processes which is not similar to the normal syringes. Due to this concern, a new design of safety syringe is introduced in order to produce a safety syringe which allows a single-handed operation and similar to the operation of a normal syringes. This paper presents the material selection process and design analysis of a newly devel-oped multi-purpose disposable safety syringe. Based on the design analysis, the force which needed to dismantle the nozzle is found to be 20 N and this value is practical for the end users. The finite element analysis had also shown that the design concept is safe and has safety feature for the user to use. In addition, copolymer is proven as the best material selection for safety syringe production.

Failure of curved brittle layer systems from radial cracking in concentrated surface loading

2005 ◽  
Vol 20 (10) ◽  
pp. 2812-2819 ◽  
Author(s):  
Matthew Rudas ◽  
Tarek Qasim ◽  
Mark B. Bush ◽  
Brian R. Lawn
Keyword(s):  
Three Dimensional ◽  
Crack Evolution ◽  
Displacement Fields ◽  
Element Analysis ◽  
Direct Evaluation ◽  
Brittle Layer ◽  
Load To Failure ◽  
Dimensional Boundary ◽  
Ultimate Failure ◽  
The Stability

A study was made of radial crack evolution in curved brittle layers on compliant support substrates. Three-dimensional boundary element analysis was used to compute the stepwise growth of radial cracks that initiate at the bottom surfaces of glass on polymeric support layers, from initiation to final failure. The algorithm calculates reconstituted displacement fields in the near-tip region of the extending cracks, enabling direct evaluation of stress-intensity factors. Available experimental data on the same material systems with prescribed surface curvatures were used to validate the essential features of the predicted crack evolution, particularly the stability conditions prior to ultimate failure. It was shown that the critical loads to failure diminish with increasing surface curvature. Generalization of the ensuing fracture mechanics to include alternative brittle-layer/polymer-substrate systems enabled an explicit expression for the critical load to failure in terms of material properties and layer thicknesses. Implications concerning practical layer systems, particularly dental crowns, are briefly discussed.

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