Your CISUG Committee:
Your CISUG Committee:
A good mesh can converge the results quickly. On the other hand, a bad mesh can ruin your day. If you are having mesh there are a few things you need to consider. Let’s first look at meshing parts. I have put a .5 mm split on a face and then tried to mesh it.
This is with a 13 mm mesh.
This is with an 8 mm mesh.
Notice that the split face does not get included in the mesh. When the element size is large enough to ignore the split face the results will be crude. The natural reaction is to reduce the element size so that all the smaller geometry can be included in the analysis. This may cause the calculation time to take much longer. My recommendation is to reduce the complexities in the geometry if at all possible. Then use shell or beam elements where you can.
At the assembly level it can be more complex. The first step should be to make sure you don’t have interference. Of course, you should follow the procedure for all parts that are in your assembly so contacts can be assigned quickly. There will be times when you do want the complex contacts to occur, for instance, line and point contacts. The mesh can fail to do the bonding of those types of contacts.
If this is the case then do the following:
-Change the global contact to Bonded- incompatible to see if assembly meshes completely.
-Use no penetration if it applies to that specific location where the mesh is failing.
-If you need to bond and need a compatible mesh to attain convergence then try to reposition the parts so they can be meshed.
-You can also control the shape of the mesh by splitting the face where the contact is going to happen.
Let's assume we have a car frame with tons of spot welds required and we are testing the welds under loads.
The load in consideration is a 250 lb load on the roof. Maybe we are travelling with bags? We defined spot welds using connectors.
You define two sets of spot welds to connect the roof to the side shells. Make sure the spot weld locations are defined and will be meshed. You will have to split the faces at spot weld location.
It is important to define no penetration condition between the parts to ensure the spot weld locations get loaded and the parts generate friction when in contact. The output of this test is a stress, displacement etc.
I hope this helps in understanding spot welds and the steps involved in solving them.
Several factors have to be taken into account while using the empirical S-N curve for a real-life model. They are, corrosive environment (Kc), surface conditions (Ks), size factor (Ki), mode of loading (Km), temperature factor (Kt), reliability factor (Kr), notch effects (Kf), fretting conditions (Kfret).
Fatigue Strength Reduction Factor =kc* ks* kl* km* kt* kr* kf* kfret
To apply the reduction factors to the fatigue strength of the selected bodies, the FS(component) of the selected components in their working condition is evaluated as
FS (component) = FS (material) x Surface Finish Factor x Loading Factor x Size Factor
The material fatigue strength FS ( material), equals half the material’s tensile strength.
Surface Finish factor: Specifies the correction surface finish factor. A surface finish correction allows the estimate of the fatigue strength of the part in its working condition. Select an appropriate surface finish type from the list or select Other to enter a user-defined value. The range is from 0.1 to 1.
Loading factor : Specifies the correction loading factor. Fatigue limits are usually determined from test specimens under bending. A specimen loaded in tension has a lower fatigue limit. Select a loading type from the list, or select other to enter a user-defined value. The range is from 0.1 to 1.
Size factor: Specifies the correction sizing factor. Based on experimental results, larger parts have lower fatigue limits than smaller parts. The range is from 0.1 to 1.
Rotating Regions can be used in analysis of fluid flow where components are rotating over different axes and/or at different speeds or if the computational domain is non-axisymmetric with respect to rotating component. Each rotating region is surronded by axisymmetric rotating region which has its own coordinate system rotating together with the component. Influence of rotation is taken into account in each of the rotating coordinate systems. To connect solutions within rotating regions and in the non-rotating part of computational domain, special internal boundary conditions are set automatically at fluid boundaries of the rotating regions. The values of flow parameters transferred as boundary conditions from adjacent fluid regions are averaged circumferentially over each rotating region. Image below shows how the averaging across the boundary affects the solution.
To solve the problem, an iterative procedure of adjusting flow solutions in rotating regions and in the non-rotating regions, therefore the entire computational domain is performed using relaxations.
In SolidWorks Flow 2015, the user can simulate enhanced rotating regions. The sliding mesh mode simulates rotating equipment where fluid flow entering the rotor is highly non symmetric with regard to axis of rotation. Since angular velocity can be dependent on time, a user can simulate motion of flow entering at an angle see image below.
There are many exciting features introduced in SolidWorks Flow 2015,watch this blog for further updates.
Please join CATI this Monday, 9/8 to learn the fastest and least expensive way to determine Will it Work? & Will it Last?
We will start with what you can do today in the SolidWorks Premium license you already own. Then we will continue our discussion about the rest of the failure modes that can impact your designs. Here are some of the analysis topics we will cover:
Register Here for the webcast on Monday September 8, 10 - 11 am cst. Special offers to be announced during the webcast.
Join us to learn how to easily simulate fluid flow, heat transfer, and fluid forces that are critical to the success of your design with SOLIDWORKS Flow Simulation. Fully embedded with SOLIDWORKS 3D CAD, SOLIDWORKS Flow Simulation intuitive CFD (computational fluid dynamics) tool enables you to simulate liquid and gas flow in real world conditions, run “what if” scenarios, and efficiently analyze the effects of fluid flow, heat transfer, and related forces on immersed or surrounding components.
You can compare design variations to make better decisions to create products with superior performance. Driven by engineering goals, SOLIDWORKS Flow Simulation enables Product Engineers to use CFD insights for making their technical decision through a concurrent engineering approach.
click here to register for this event on August 27, 2 - 3 pm cst.
SolidWorks Plastics brings easy-to-use injection molding simulation directly to the designers of plastic parts and injection molds, as well as advanced CAE analysis. It simulates how melted plastic flows during the injection molding process to predict manufacturing-related defects on parts and molds. You can quickly evaluate manufacturability while you design, to eliminate costly mold rework, improve part quality, and accelerate time to market. A Results Adviser provides troubleshooting steps and practical design advice to help diagnose and avoid potential problems.
Lets consider a cavity and insert scenario, similar to the keys we carry around everyday. The metallic insert (key) is incased in plastic and we are trying to figure out what does it take to produce thisi configuration using injection molding process. Come to think of it there are many such examples in our day to day lives. eg knives, remote controls, toys etc.
This is a two part model with the yellow being plastic and blue part is metal. In SolidWorks Plastics I can identify the 2 parts separately during mesh and define them as cavity and insert. SolidWorks Plastics generates tetrahedral mesh to capture geometry.
We then specify Fill, Pack, Cool and Warp conditions. Using the built in animation tool a user can figure out the fill pattern and time. Other Fill parameters such as Pressure, Temperature, material damage, Volumetric Shrinkage, Ideal Cooling time are calculated as well.
Pack tool calculate what happens in the cavity during pack stage of injection molding process. Residual stress calculated during Pack analysis is a key indicator of warpage. When doing what-if analysis to figure out ideal thickness, material and process parameters etc, it is critical to make sure the residual stresses are going down to ensure design improvement. Residual stress is the stress left in the material due to injection molding process.
SolidWorks® Plastics makes it easy for companies that design plastic parts or injection molds to predict and avoid manufacturing defects during the earliest stages of design, eliminating costly rework, improving quality, and accelerating time-to-market. Fully integrated with SolidWorks CAD, this intuitive software helps part designers, mold designers, and mold makers optimize designs for manufacturability without leaving their familiar 3D design experience.
SolidWorks Plastics helps evaluate manufacturability of parts and molds. SolidWorks Plastics simulates how melted plastic flows during the injection molding process to predict manufacturing related defects on parts. An intuitive user interface leads you through a guided analysis set up, intelligent defaults and automated processes ensure that simulations are set up correctly.
In this webcast see how SolidWorks Plastics gives you tools to quickly identify potential problems so you can make changes early in the design process.
The following topics will be covered:
Register now for July 21 webcast! Limited seats.
SolidWorks Simulation helps analyze symmetrical and unsymmetrical composite layups, as well as composite sandwiches. Each layer can be defined by a unique set of material properties and orientation, giving the designer maximum control to find the optimum layup and material for maximum product performance.
The failure criterion for composite materials is very different than for metals. Composite materials do not yield; rather, the fibers delaminate and fracture. SolidWorks Simulation reports the FoS against failure according to the Tsai-Wu and Tsai-Hill failure indexes.
SolidWorks Simulation uses FEA methods to discretize composite components into shell elements and uses stress analysis to determine the response of parts and assemblies due to the effect of forces, pressures, contact between components etc.
Stress plot displays the maximum stress values of the specified component (envelope plot) across all plies. The program includes the Top and Bottom faces while searching for the extreme value across all plies.
Tsai-Hill criteria is best applied to composite materials that have equal strengths in tension and compression and cross-fiber stress is primarily in tension.
The Tsai-Wu criteria is best applied to composite materials that have inequal strengths in tension and compression and the cross fiber stress is primarily in tension.
Max stress criteria is best applied to composite where the cross-fiber stress is primarily in compression.
To understand complex component responses with analysis of composite parts use Solidworks Simulation. You can then optimize material selection and the number and orientation of the composite ply layup to ensure quality, performance, and factor of safety (FoS).