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Overhead Electrical Conductor fatigue testing: a new standard

The International Electrotechnical Commission (IEC) just released a new international standard titled: "Overhead lines - Method for fatigue testing of conductors". IEC 62568. Edition 1.0 2015-07. www.iec.ch . It closely follows previous CIGRE and EPRI publications on this topic:

CIGRE SC B2 WG11 TF7 "Fatigue Endurance Capability of Conductor/Clamp Systems - Update of Present Knowledge" CIGRE TB 332, 2007, Paris.

Seismic Evaluation of Petroleum Storage Tank

I´m doing a plastic collapse evaluation as per API 579-1 Appendix B1, and one of the load cases is Earthquake loads. 579 refers to ASCE 7, which for tanks refers to API 650 Appendix E. The approach in 650 is a static equivalent lateral force seismic analysis where you find equivalent lateral forces and moments according to some likely earthquake spectrum. It seems that what you do is apply these at the top of the tank shell, which mimics the overturning and shear behavior, assuming the tank doesnt slide from inertia. 

How to calculate Impedance (Electrical output variables) in a basic Piezoelectric modelling

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Hello All,

I am a relatively new user to Abaqus. I am working on piezoelectric steady state dynamic analysis of a transducer. Currently I only have a cuboid piezo transducer. My main aim now is to get the Impedance values for a given input voltage. I am exciting the transducer at a frequency of 1 kHz. I would use the relation of Z = Input voltage / Output current.

Door closing effort

Hello everybody,

A cable bending stick-slip analytical model

Single strand cable bending, stick-slip, analytical models require that a choice be made between two contact modes between adjacent wires: either radial (between layers) or lateral (between same layer wires). In most recent models (e.g. Papailiou’s) radial contact is selected. A “lateral contact” model has been presented by Panetti in 1944 and can be found in the proceedings of the Turin Royal Academy of Science. A translated version from Italian is proposed in the attached file.

Reservoir Modeler. Eclipse to Abaqus. Geomechanical Coupling

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Hello, Everybody, who is studing reservoir geomechanics,

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The Cable Connection – Choosing the Perfect Lifeline for Your Machines

With the availability of different brands and grades of cables in the market, it can be pretty challenging to narrow down the options to a few good ones. As with several other things related to wires, a high price tag or big brand name doesn’t actually help in making the right selection. Instead, one has to look out for particular characteristics and specifications for picking the right cable.

Helical Strand Mechanics Modelling

Some 2014 papers on the mechanics of helical strands: cables and electrical conductors

Cable FEA modelling

A 2014 paper on cable FEA modelling

An early stick-slip model for cable bending analysis

One approach to helical strand (cable or overhead electrical conductor) bending analysis puts the emphasis on friction rather than on elastic curved rod behavior. Based on Coulomb’s laws of friction, it leads to stick-slip models where strand  bending stiffness varies with imposed curvature (Papailiou, 1995). Such an approach can be traced back to a Ph.D. thesis by H. Ernst, in 1933. This work is in fact often referred to in cable analysis reports. An English translation (with a short presentation) of the dissertation analytical part is attached.

Vibrations

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How to do a frequency sine sweep in abaqus CAE. I want to get a frequency response curve (mises stress,U) through applying a forcing function on a turbine disc to estimate stresess at resonating conditions.

Helical Strand in Bending

Several approaches have been used to deal with the complex problem of helical strands in bending. One of them is based on Love’s curved rods theory. It has first been used by Costello in his classical monograph “Theory of Wire Rope”. It has been extended by Sathikh et al. in several papers. A new contribution from this group is a Ph.D. Thesis by D. Gopinath : “Some studies on bending response of the stranded cable under free bending and constrained bending”, Anna University, Chennai (India), October 2013, 121 pages.

Justification for use of Riks method to investigate gross plastic deformation

Hi, my question is on the use of Riks and other Arc length methods when analysing  a system for gross plastic deformation. ASME B&PV code , in its investigation for Gross plastic deformation as a Load at which convergence does not take place. Now, as far as I understand, Newton Raphson method fails at locations of singularity in the stiffness matrix and also at Bifurcation points, it can trace the unstable primary paths. Both these issues can be overcome ( provided the limit point is not too sharp) by Riks and other Arc length methods.

New Open Access journal: Case Studies in Engineering Failure Analysis

Read over 40 open access articles from Case Studies in Engineering Failure Analysis

Case Studies in Engineering Failure Analysis provides a forum for the rapid publication of short, structured Case Studies in Engineering Failure Analysis and related Short Communications, and will provide an essential compendium of case studies for practitioners in the field of engineering failure analysis and others who are interested in the ways in which components fail.

Fatigue of Overhead Electrical Conductors

A new paper on  the OEC fatigue problem: “Determination of Early Failure Sources and Mechanisms for Al 99.7% and Al-Mg-Si Alloy Bare Conductors Used in Aerial Transmission Lines”, by S. Karabay and E. Feyzullahoglu. Paper has been accepted for publication in March 2014 in the “Engineering Failure Analysis” journal. Abstract can be found on-line:  http://dx.doi.org/10.1016/j.engfailanal.2013.12.002

CABLE BENDING ANALYSIS THOUGH FEA

Single strand cable (spiral) bending and OEC (Overhead Electrical Conductor) bending are somewhat similar problems. This is the reason why the following new paper is noteworthy within the context of this blog. It emanates from a Slovak team: S. Kmet, E. Stanova, G. Fedorko, M. Fabian, J. Brodniansky. Title : “Experimental investigation and finite element analysis of a four-layered spiral strand bent over a curved support”. Published in “Engineering Structures”, Vol. 57, December 2013, pp. 475-483.

Simulation Thermal Mechanics of PCB with Vias Using Ansys

Hi, I am new to this blog & asking for help from you! If any one know that Ansys has 3D composite element that we can use to simulate PCB with Metal Vias (In-plan Fiber glass & epoxy & Out of Plan Metal Cylinders. Tx

Failure Criteria

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Hello Friends,

I am struggling to correlate FEA results with experimental
results. I work on polymer parts reinforced with glass fibers. I have stress
strain curves for the material till failure. My FEA results are 50% off from
the experimental results. The model is setup correctly.

Bending of cables : a stick-slip model

Bending of cables and, for that matter, of any helical strand system (such as overhead electrical conductors) is a challenging solid mechanics problem, with geometry and multibody frictional contact aspects. As seen in several recent papers, one workable approach is based on Coulomb’s laws of friction.  An earlier contribution by Lehanneur (1949), published in French, has generally been  ignored. The attached report presents a translation into English (including a presentation) of this most interesting work.

J Integral calculation for an Axisymmetric Problem with crack in Ansys

Hi all,

I am working on Crack growth analysis of Turbocharger wheel and shaft assembly. I have simulated it as an axisymmetric problem with fine mesh around the cracktip(in Ansys). Element used is Plane182.

I have to compare the K1 and K2 values obtained from both the Displacement Extrapolation Method and J-Interal method. 

I got the K1 an K2 values at the cracktip location by defining path using displacement extrapolation method.

But, I was not able to get the Stress intensity factor values (K1 nad K2) using J-Integral Method.

Dynamic force on a closing mitre gate

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      I'm looking at the design forces acting on a vertically hinged mitre gate for flow control in a canal, (open channel flow).  We know the maximum volumetric flow rate of the water flow when the gate is closing.  How can I estimate the maximum force exerted on the gate as the water causes it to slam shut.  

Overhead Electrical Conductors and High Intensity Wind

Effect of tornadoes on electrical power lines has been discussed by Sébastien Langlois in his M.Eng. thesis : “Design of Overhead Transmission Lines subject to Localized High Intensity Wind”. McGill University, Montreal, QC, Canada, 2007 (available on-line on the “Theses Canada” portal). Work presents various national and international standards (ASCE, Cigré, IEC etc.), historical cases, as well as models for numerical simulation.

Aeolian vibrations and fatigue of Overhead Electrical Conductors

An interesting presentation of the state of the question by  Dr Louis Cloutier, in 2008.

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