Sometimes it's the little things that escape us. So I thought it would be a helpful reminder to share with you some data reuse tips for SolidWorks Simulation, SolidWorks Motion, and SolidWorks Flow Simulation. These are not fancy, nor are they rocket science (although rocket scientists do use SolidWorks Simulation) but they might help you save a few seconds of your precious time here and there.
SolidWorks Simulation-
Motion-
Key frames, denoted by diamonds of varying color, can be copied and pasted within a Motion study using Control-C (copy) and Control-V (paste). Presently, motion elements such as springs and motors can not be copied to the Windows clipboard. But, again, the Design Library can be utilized to store often reused Motion elements.
Flow Simulation-
I hope you've found these simple tips useful and time-saving. If you have other ideas that you'd like to see us blog about, please don't hesitate to contact us.
Have you ever received this error message while trying to run a static SolidWorks Simulation study with mixed mesh? (shells and solid elements)
Or... how about this one?
Both errors imply that there are something wrong with the study's fixtures or restraints. Is that always the case? No. Mixed meshes, due to the differing number of Degrees of Freedom the elements possess, introduce their own instabilities aside from loads and restraints. In geometrically simple structures, troubleshooting these issues is relatively straight-forward and the mantra, "local bonded contacts," will usually save you.
In complex models, however, the process of troubleshooting may become daunting. So I suggest an alternative to "hunting and pecking" through your contacts: Frequency Study.
The Frequency Study is one of the many study types found in SolidWorks Simulation Professional (and, by default, Simulation Premium). The results of said studies include the natural frequencies a structure vibrates at as well as each frequency's "shape." And while a frequency study can aid us in the design of our structures, my purpose for encouraging you to consider them now is for a means of finding contact pairs that should be bonded but were missed.
In a structure that has no external restraints or- in other words- is naturally unsupported, its first 6 modes will reflect the 6 natural degrees of freedom for any body in space: three translational modes and three rotational modes. Therefore, when listing the "Resonant Frequencies" of the structure (by right-clicking the study's Results folder) one will see zero or almost zero values for those first six modes. Past those first six modes, if you see additional zero (or almost-zero) values then you can be sure that bodies in your structure are displacing rigidly, separating themselves from the rest of the structure. Creating a mode shape plot (Displacement Plot) for those zero-valued modes and then animating it will solidify this in your mind.
If you are using SolidWorks 2011 and have Simulation Professional or Premium, I encourage you to download the attached part file. You'll find a number of static and frequency studies to illustrate the above.Download Mixed Mesh Frequency Analysis
Special thanks to my colleague, Dave, for making me think about this.
In this article, we are going to determine Dynamic Torque generated by Water at various position of the Valve. The given value geometry is checked in SolidWorks and previewed using SolidWorks Flow Simulation "Check Geometry Options". There were no penetration/interferences in this simplified model.
Flow Analysis - Operating Conditions:
Pressure and Velocity Plots at 23 degree open Condition:
Pressure and Velocity Plots at 67 degree open Condition:
Summary of Results:
SolidWorks Configuration Y-Component of Torque (lbf-in) Comments 23 degree open 58254.36127 Total cells=346747, Results converged 67 degree open 3844.252027 Total cells=261074, Results converged Full open -0.699287861 Total cells=274276, Results converged
Conclusions & Advantages of using SolidWorks Flow Simulation :
My previous article did give
you some insights about importing motion loads in Simulation 2009. Time and
again solidworks Simulation has proved that its trying to make our life easy
every year with new enhancements. In 2010, it has now added the Simulation
Setup inside motion. Once you are all set with your required mechanism in
Motion, all you need to do is go to the Simulation Setup and it will guide you
through the process. You can specify the mesh density, time steps and material
property during the simulation setup process.
As we click on “Calculate” to compute for our motion study, we need to go with “Calculate Simulation Study” and then obtain Stress, Factor of Safety and Displacement plots. The cool feature is that as you would visualize any normal motion study, you can also view the Simulation plots changing in real time. It again depends on the time step that you specify during the Simulation Setup within the Motion Study.
All the above mentioned was motion analysis with respect to time. Solidworks Simulation team has also come up with “Event based Motion” as a part of Simulation Professional in 2010 version. This could be easily explained from the fact that one event triggers another event in a sequence. This type of motion analysis is very important when we are unaware of any time factors in the motion study.
As the title describes, you may have often come across a situation where you need to import the motion loads on any one of the component/part and the moment you click on simulation-Import motion loads, you do not see any part mentioned in the “Available Assembly Components”. This might lead you to think whether – did the motion study go through? or is it a bug in the software ? Well the answer is simple. In Simulation, you have to make sure that the components of interest has to be a single part i.e. child of the main assembly rather than being a part of a sub assembly. Any part belonging to a subassembly will not show up in the available components list. In Simulation motion, where you have to often deal with mates, redundancies and so on, it is always better to think about the parts of interest in the beginning cause this might lead you to spend long hours in re-creating the mates while trying to dissolve the subassembly.
There is another work around for the above problem. This can be done by using the command “Dissolve sub assembly”. All you need to do is right click on the sub-assembly and select “Dissolve sub assembly”. This will help you to break the parts under the sub-assembly and make them the children of the main assembly. Again, as mentioned earlier, care has to be taken before proceeding with the motion study as this might leave you with all of errors in mates.
I hope, this will give you a heads up on how to proceed with a motion study and save you some time and focus more on simulation (motion and FEA) rather than re-creating the assembly mates.
What is Creep?
Creep is a time varying, permanent strain due to long term application of constant or near constant stress level. Creep is observed in most engineering materials especially metals at elevated temperatures, high polymer plastics, concrete, and solid propellant in rocket motors.
Creep Analyses require detailed materail data that are dependent on duration of load and the magnitude of initial stress and temperature. Creep is not a significant concern for most metals until operating temperature reach 35% to70% of respective melting points.
Creep Curve:
Creep curve is a graph between strain versus time. Three different regimes can be distinguished in a creep curve; primary, secondary, and tertiary (see the following figure). Usually primary and secondary regimes are of interest.
Follow Simple and Easy Steps to Simulate Creep Study in SolidWorks Simulation:
Step_1: Define Nonlinear as a type of study
Step_2: Define the materail properties with Creep effects
Step_3: Define Operating Conditions - Loads/Restraints and Mehsing
Step_4: Properties set up, Run & Post Process the results
Conclusion:
Based on this creep analysis study using SolidWorks Simulation (Premium Module), the model set up, meshing and analysis run was done very quickly. The challenge was to get the Creep constants for the materail along with temperature data.
In order to run any Nonlinear Creep Analysis, Graphics Systems Simulation team request all users (designers, engineeers and program leads) to work on gathering materail stress-strain curves and creep constants inputs as a parrallel activity to desgining the parts and assemblies. This will save tremondous time and cost in product development. SolidWorks Simulation Premium, which is integrated within SolidWorks has all features necessary to do Nonlinear and Linear Dynamic analyses.
Most of Graphics/Systems customers recovered the software investment costs within few months time!
I am not saying that generating the mesh is very easy if thats really what you are thinking. We often use the h-adaptive or p-adaptive techniques to get a refined and acceptable mesh. Thats true for the static analysis. How about a frequency or a buckling analysis? Have you every tried using the h-adaptive and p-adaptive mesh for these two studies ? I tried too and did not succeed. However, if you complete the static analysis with the required type of adaptive technique and copy the mesh onto the frequency or buckling analysis, it would let you copy the mesh. Its true that the displacement values obtained from the mode shapes of these two respective studies do not mean much but those of you who would like to use the required adaptive technique, this is the way to go. Well, that was easy.
Another technique I want to share with you is applying the Mesh control. The way you start any study is to first define materials, apply contact conditions, apply loads, generate mesh and run the analysis. This order is very useful when you want to apply the mesh control. Consider faces between any two parts for which the contact set has been defined. If you want to apply a refined mesh control on these two faces, you would pick them one after the other, right ? Some times, this can be painful when you try to hide one part and select the face and repeat the same process for the other face selection. You can also use the "Select Other" option but that can be painful as well with too many clicks. Well, all you need to do is highlight the contact set from the Study tree and then right click on mesh and select mesh control. The faces for contact pairs have already been selected. Well, that was easy, isn't it ?
