Element Quality Check Criteria in FEA meshing - FEA applications and Tutorials

Quality of the element is very important criteria , in FEA pre-processing. Higher the qulaity of the mesh, we can get reliable results given that you have given perfect boundary conditions.

At the same time, we should also consider the memory limitation of the computers available with us. So , we should optimize the FE model equally considering the cost of the solving and accuracy that is needed.

Understanding Element Quality Checks

Quality checks measure different aspects of an element's deviation from an ideal size and shape. That ideal shape depends upon the element type.You can choose one or more checks and set threshold values, or limits for deviation, for each. You can perform these checks on shell and solid elements.
There are several ways to check your mesh. You can use:

• Auto Mesh Checking to have the software automatically evaluate aspects of element quality while it generates a mesh

• Element Quality Checks to set quality threshold values and evaluate element quality once you've generated a mesh

• The various element quality icons and menu commands, such as Coincident Nodes or Coincident Elements, to run individual quality checks

Once you've identified element quality problems, you can use tools such as Plump or Straighten Edge to fix distorted tetrahedral elements. You can also use the Node or Element menu commands to adjust other elements.
After you've checked the mesh, you can generate statistical data on element quality or create a result set and display the elements in Post Processing. You can also filter the selection of elements from the results of these mesh checks.

Understanding Quality Threshold Values

This table lists the possible threshold values for each type of element and shows how they're calculated. In this table:

• X = supported by Quality Checks

• LX = calculations use linearized edges

• SX = calculations use shape functions

• LMX = calculations use linearized midside to corner edges

Quality Check	Threshold1	Threshold2	Quad Shell	Tri Shell	Solid	Linear	Parabolic	Cubic
Skew	(>) 0-360	-	X	X	-	X	SX	SX
Warp	(>) 0-180	-	X	-	-	X	LMX	LMX
Taper	(>) 0-1	-	X	-	-	X	LMX	LMX
Aspect Ratio	(>) 0-100	-	X	X	X	X	LX	LX
Distortion	(<) 0-1	-	X	X	X	SX	SX	-
Stretch	(<) 0-1	-	X	X	X	X	SX	LX
Jacobian	(<) 0-inf	-	X	X	X	SX	SX
Element Size	(<) 0-inf	(>) 0-inf	X	X	X	X	LX	LX
Quad Included Angles	(<) 0-90	(>) 90-180	X	X	X	X	SX	SX
Tri Included Angles	(<) 0-60	(>) 60-180	X	X	X	X	SX	SX

Using Automatic Mesh Checking

Nowadays, every pre-processing software comes with automatic mesh checking feature. We can use Auto Mesh Checking to have the software automatically evaluate element quality while it generates a mesh. The Automatic Mesh Checking form lets you specify values for checks such as Distortion and Stretch.

This form also lets you control whether mesh smoothing is turned on for meshes that contain linear or parabolic tetrahedrons. Mesh smoothing improves stretch and distortion. 

How to solve Free element Edges in FEA meshing - FEA applications and Tutorials

Handling Free Element Edges

When we combine elements within a mesh, it may result in the creation of free edges in the interior of the mesh. It is mandatory to cross check and ensure that there are no free edges at the interior of the mesh , before sending the model to Solver.

For example, let us assume we combined four linear elements to create a single linear element (A). And now, the mid-nodes on the new element aren't connected to this element; they're connected to surrounding elements (B). (The new element isn't a 6-noded quadrilateral hybrid element.) Therefore, free edges occur in the interior of the mesh where the new element is adjacent to existing elements (C).




You can eliminate free element edges in one of two ways:

• Use Combine Elements option to propagate the combined elements throughout the mesh. This eliminates all free element edges. Here:

A = mesh containing combined elements

B = combined groups of four elements

C = Free Element Edges verifies there aren't any free edges in the interior of the mesh.

• Stitch the new elements into the mesh by using various combinations of Split Elements, Combine Elements, Delete, (Create) Element, and Node Connectivity commands. 

C = Use Free Element Edges to verify that there aren't any free edges in the interior of the mesh. 

Defining and Generating a FEA Mesh - FEA Practical applications and tutorials

In general , the basic platform and tools for Meshing task is common in all FEA pre-processing softwares like NX Nastran, Hypermesh,Cosmol, Abaqus, Ansys etc. This article will give a brief overview of the basic of mesh generation technique in FEA.

Defining and Generating a Mesh

The Meshing task will provide tools to help us to define and generate a FE mesh. We can

• use the geometry checking tools to verify that your geometry is ready for meshing
• define parameters for the mesh
• preview the mesh before you generate nodes and elements
• generate the mesh based on the mesh parameters
• check the quality of the mesh
• update the mesh after solution
• modify individual nodes and elements as necessary

Defining a Mesh

When we define a mesh, we should specify parameters such as:

• mesh type. Mesh generation can produce either regularly-spaced finite elements (mapped mesh) or less restrictive free elements (free mesh).
• element type and length
• elements' physical and material properties
• We can always choose default or previously-defined settings when you create a mesh. Often, however, you will want to control the meshing process more by changing some of the default parameters

Meshing Limitations

• We can't mesh adjacent entities with a different element order defined. For example, we cannot define a linear element type (say four node element) for a mesh on one surface (x) and then define a parabolic element type ( say eight node element) for an adjacent surface (y). This creates a mismatched element order where the surfaces join (z).

• We can't mesh adjacent entities that have a free and a mapped mesh defined on them.

How to claim theft insurance for stolen Apple MacBook in India

If your Apple Macbook is stolen, the first step is to track using Findmymac application , using your serial numbre of your stolen macbook.


If you are not able to find your stolen device, then the next only way is to claim theft insurance if you have protected your device with theft insurance policy.

As recommended by Apple,

If you didn’t set up Find My Mac before your Mac was lost, or you can’t locate it, these steps might help you protect your data:

1. Change your Apple ID password to prevent anyone from accessing your iCloud data or using other services (such as iMessage or iTunes) from your Mac.
2. Change your passwords for other accounts you use with your Mac, including email, banking, and social sites like Facebook or Twitter.
3. Report your lost or stolen Mac to local law enforcement. They might request the serial number of your computer. You can find this information on the original box or receipt you received when you purchased your Mac, or on Apple's My Support Profile site if you registered your Mac.

After registering an FIR that your device is stolen, approach your insurance company to claim theft insurance with the proof of FIR you have registered.

Tamil Nadu : Government Fixed rate for Auto Rickshaw | Complaint number for Extra Fare in Chennai

Since lot of complaints are reported against high fare collected by auto rickshaw , specially in Chennai urban and sub urban location, Tamil Nadu government passed an GO to regularize the Auto rickshaw fare around the Chennai Metro Politan area.

1.  Minimum charge for first 1.8 Kilometers : Rs 25.
2.  For each additional Kilometer. : Rs 12.
3.  Detention (Waiting) charges : Rs 3.50 for every five minutes.
4.  Night service charges (between 11.00 p.m and 5.00 a.m) : In addition to the total fare calculated at the above rate, an additional charge of fifty percent of the total fare.

As per the motor law, every auto rickshaw should have been fixed with digital electronic fare meter, which is enabled with GPS and Printing features. These meters will be provided by the government at free of cost.

Auto Rickshaw : Helpline Complaint number :

When you face any issues related to extra fare or other security issues, you can call to the Complaint number for Auto rickshaw : 044-66334346

The important thing is to provide the register number of the Auto rickshaw. The name and details of the complaint number will not be disclosed.

Chennai local Sub urban train return ticket validity | Clarification of Rules

For most of us, the statements of validity for return ticket of Chennai local Sub urban trains is a mystery. This article will clarify the rules of return ticket, so that you can save some money by knowing the correct rules framed by southern railways.

• The onward journey (start of journey) should commence (start) within one hour of the purchase of the train ticket.
• The return ticket is valid up-to the Midnight of the next day, from the date of purchase of return ticket.
• The return ticket is valid only for local suburban train , local fast sub urban train. The ticket is not valid in Express trains and Intercity trains.

For example, if you buy the ticket on Saturday morning 9 AM, then you should leave the station where you buy the ticket before 10 AM.
And you can use the return ticket, up-to 11.59 PM of the Sunday midnight.

These rules will be clearly printed in the back side of the ticket. You can refer at the time of purchase of the ticket.

EZTV : Unofficial Retirement due to cloning of its Own domain | EZTV vs ETTV

After several piracy issues and cloning of its own domain , the original EZTV domain was unofficially retired during early 2014. The new clones of eztv domain is run by unknown volunteers.

EZTV Hostile takeover

Since October 2007, EZTV was using the EZTV.it domain name. But under pressure from copyright holders, The Italian .it registry lodged a complaint over some paperwork.Facing a possible confiscation of the EZTV.it domain name, they saw no other option than to switch to a new domain. The EZTV.it domain name was suspended, and a couple of months later was taken over by scammers attempting to claim EZTV as their own. But unlike the real EZTV this .it domain does open windows with advertisements.

As of 25 April 2015, the EZTV.ch and the EZTV-Proxy.net the "semi" accepted proxy are under control of "EZCLOUD LIMITED".^[11] Simultaneously with the takeover of the EZTV.ch domain and the EZTV-Proxy.net proxy, the scam group "EZCLOUD LIMITED" started attempts to take over the online identities by impersonating them on their own clone of the original websites, further assimilating the brand name and disrupting the workings and communication of the original group and attempting to gain revenue via an unofficial EZTV Bitcoin and adverts on these hijacked sites. "EZCLOUD LIMITED" gained access to the EZTV.se domain via the registrar and reset Novaking's information allowing them access to the domain accounts for EZTV, using this access they hijacked the EZTV domains and locked Novaking out.All the hijacked domains now redirect to EZTV.ch.

The original EZTV website was officially retired around on 29 April 2015 with the topic of the IRC channel where EZTV was discussed saying: "DO NOT USE THE SITES! They are not ours anymore. Thanks for all the fish. As of 5 May 2015Rarbg, BT-Chat. and other sites have removed EZTV as an affiliate and are taking steps to stop "EZCLOUD LIMITED" indexing releases. KickassTorrents, BT-Chat and The Pirate Bay have since suspended or deactivated the official EZTV accounts and added warning to the old releases, also ex-EZTV staff continue their warnings that people should avoid the scam site that is left behind.

Google have started to no longer serve web results from EZTV and instead provides the articles relating to the hostile takeover by "EZCLOUD" and the possible suspension of the .it domain by the Italian registry

EZTV vs ETTV 

IBtimes criticized that EZTV and ETTV are different distribution groups that are operated by with an implicit relationship.

 No, contrary to popular belief, EZTV and ETTV are not partners in crime. Yet the sites seemed to operate in a kind of implicit partnership: If one didn't offer the newest episode of “Game of Thrones” within an hour of the show's ending on HBO, the other almost certainly would. But ETTV is actually an offshoot of the ExtraTorrent tree of websites, which TorrentFreak predicted would be the No. 3 most popular torrent sites of 2015 (three spots higher than the dearly departed EZTV).

A cursory glance through the most popular torrents on the biggest aggregators show that the most recent TV episodes are almost exclusively being distributed by ETTV