FEA : Understanding and Creating Nodes | What is a node in Finite Element Analysis

What is a node in Finite Element Analysis

• A node is a coordinate point in 3D space. Nodes define and connect elements in a finite element mesh.
• A node can have up to six degrees of freedom (DOF) for structural analysis: three translational and three rotational.

Creating and Managing Nodes

The meshing software automatically generates nodes during the meshing process. You can also use the Node icons, the commands on the Node menu, and the icons on the Manual Meshing tool-bars to create individual nodes.

The Node menu includes commands which let you create, orient, modify, and manage nodes.

• We can use Reflect to generate nodes by reflecting existing nodes. 
• We can also use the Node commands to manage the nodes in your model. 
• We can display, list, and delete selected nodes.

Understanding Node Labels

Each node has a label that is a unique numeric identifier you can use to identify individual nodes.
When we create a new node, the pre-processing meshing software automatically lists the next node label available for the model. The software won't let you specify a node label that conflicts with an existing label.

FEA: Dragging Nodes in FEA mesh (thin shell 2D elements) | Ansys | Hypermesh | Solidworks

To meet the quality criteria like threshold angles, Jacobian ratio, aspect ratio, warp, distortion etc, we can manually drag the nodes of the elements.

Therefore, Dragging a Node can interactively re-position nodes associated with 2D type elements, such as thin shell, plane strain, plane stress, axis symmetric solid, plate, and membrane.

When you drag a node, it maintains associativity with the surrounding elements and the underlying geometry. As you drag the node, the software previews how the elements associated with the node will be affected.

In general, we can only drag one node at a time. However, any mid-nodes adjacent to the selected node will also move. If you drag a node in a mesh that contains higher order elements, such as parabolic or cubic elements, the pre processor software (Hypermesh, Ansys, Solidworks) translates the mid-nodes to preserve their initial characteristics.

Requirements for Dragging a Node on Geometry

If a node is constrained to:

• an edge or a wireframe curve, you can reposition the node along that edge or curve.
• a surface, you can reposition the node on that surface.
• a section, you can reposition the node on any surface within that section.

Note: You can't drag a node past the edge of a hole or fillet.

You can't use Drag (Node) to re-position:

• nodes on anchor nodes
• nodes associated with vertices, connectors, or centerpoints
• nodes associated with geometry-based other elements (such as a spring, rigid bar, or lumped mass)
• nodes associated with point-based geometric boundary conditions

Dragging a Node on Geometry

1. Pick the node you want to reposition.
2. Move the cursor to drag the node. As you move the mouse, the software updates all adjacent element edges in real time.
3. Use mosue buttons to drop the node in its new location,

Requirements for Dragging a Node Not Associated with Geometry

Drag (Node) also lets you drag nodes in FE models that don't contain any geometry, such as those FE models created with the bottom up meshing technique. Before you can reposition a node that isn't associated with geometry, you must first pick the plane in which you want to drag the node. The default drag plane is the average of the local normals of the adjacent elements.
Dragging a Node Not Associated with Geometry

• Pick the node to reposition.
• Pick the plane in which you want to drag the node.
• Move the mouse to drag the node or use the mouse button options 
• Use mouse buttons to place the node.

We can also pick Drag (Node) from the Element Quality Checks form to improve particular aspects of element quality. For example, if a quality check reveals a high amount of skew in a particular region, we can try repositioning nodes in that area to reduce skew.

FEA : Post Processing Tools for Ansys, Hypermesh, NX Nastran, Solidworks | Visualizer for FEA results

FEA : Post Processing Tools

Once the model is solved, we need to review and interpret results. The Post Processing task and the Visualizers available in CAE packages like Hyperworks (Hyperview), Solidworks, Ansys, NX Advanced simulation etc provide many graphical techniques for displaying results data.



In addition, Post Processing provides capabilities for manipulating the data for further understanding. Specific result quantities, such as principal stress, can be derived from the input data without going back to the solver.

We can also define our own results calculations, for example, to define failure criteria (Vonmises stress, max principal criteria, minimum principal criteria etc) . Data can be sorted across a range of load sets to find worst-case conditions. Output of specific numerical data is available by selecting locations on the screen.

Text information and reports are still often needed to communicate with others. The Simulation software provides capabilities for getting sorted tabular reports, displaying specific model and results quantities in text form directly on the FE model, and placing 

FEA : Steps for Collapsing and Removing Triangular Elements | Meshing in Ansys, Hypermesh, Solidworks

When we use Element Collapse to remove triangular elements from your model, we should be very careful in selecting the elements to collapse.
In many cases, we won't want to collapse all elements that don't meet the specified quality criteria like, included angle threshold.
For example, depending on your geometry, when you use Element Collapse, the resulting mesh may not have nodes at the vertex of two edges.



For illustration, just assume a simple model of a block with a shallow groove cut through the top. and an FE models created and defined a mesh of linear triangle elements on all surfaces.

Now, assume We used the Tri-Inc Angles option on the Element Quality Checks form to check the model for triangular elements with included angles smaller than 15°.

Now the software will

• show a group of the elements that failed the check.
• show the same group of elements displayed within the context of the model's surfaces.

As case 1, we can make Element Collapse to remove all the elements that failed the initial Tri Inc Angles check. By collapsing those elements, we significantly change the relationship between the mesh and the geometry in the region of the groove. Specifically, the software no longer generates a node at the vertex between the two edges


In case 2, we can make element Collapse to remove only the eight elements in the middle of the groove. Notice the difference in the resulting mesh at that vertex. However, also notice that there is now no longer a node at a different vertex.

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Fedex Courier: Fedex delivery exception customer not available or business closed - No delivery Attempt

FedEx is one of the leading courier delivery service company which has its familiarity in most parts of the world including USA, India, Pakistan.

• Courier Dispatched → means the courier package is sent off to the destination by the sender. If you see this tracking status, then your courier is on the way to your destination.
• In transit → means that the courier package is on the way to destination ( in moving vehicle or in Fedex Facility)
• Delivery exception → an unexpected event is preventing delivery of your Fedex Courier Package. The status exceptions include a customs delay, no one to accept delivery of your package, holiday, missing documentation, business closed etc.

We can easily check the current status of your courier , in FedEx official website using the tracking number .

Some of the FedEx courier status statements are formed little vague, to interpret the accurate meaning of the status. So, possible the information may be in unclear manner which makes it difficult to understand for the reader / observer

One of the familiar FedEx courier status of that kind is delivery exception ,

Delivery Exception -  Business Closed - No Delivery Attempt

It means that you have given delivery address as a Business building (Office address). Sometimes, the delivery person may try to deliver during weekend like saturday and if the provided building is closed, then the tracking status will be updated as Business Closed - No delivery attempt.

So, if you see this status for your FedEx courier package, then no need to panic , because there is no fault in your parcel, but it will reach you one day later. If it is emergency, then you can contact Fedex customer care number for your country.

Delivery Exception -  Customer not available 

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So, if you see this status for your FedEx courier package, then no need to panic , because there is no fault in your parcel, but it will reach you one day later. If it is an emergency parcel, then you can contact Fedex helpline number with your tracking id.

FEA : Response Analysis in Structural Finite Element Analysis | Ansys | NX Advanced Simulation | Hyperworks

Response Analysis

The Response Analysis task is usually done to interactively evaluate the responses of a structure subjected to various static and dynamic excitation. The responses are generally calculated using a modal approach, means that the FE model is solved for Eigen value analysis and based on the calculation, the response of the structure for desired input excitation is evaluated and studied.

Types of Response analysis

Response Analysis can perform five types of response analysis:

• Static → Static force would be used for exciting the model
• Transient → Time domain functions are used to vibrate the model at desired input nodes
• Frequency (sinusoidal) → Freq Vs Accel function is used to vibrate the model
• Response spectrum  → A manually created spectrum function is applied as input excitation
• Random vibration → PSD (Power Spectral Density) function is used as input excitation.

CAD / CAE packages like solidworks, Hyperworks, NX, Ansys comes with an inbuilt Response Analysis tools, for which a seperate license may be needed apart from CAD modeling features.