Search the Community
Showing results for tags 'optimisation'.
Found 21 results

sir, for Modal and Stiffness(torsional and bending) analysis of ladder frame chassis, is there any significant difference in results when I use stick contact between frame and crossmembers or when I use shell/rigid weld elements to connect crossmembers and long members?

I am trying to find out optimum location of crossmembers wrt Long members. The crossmembers are bolted to brackets+crossmembers whose locations are varied using hyperstudy. Will there be any effect on above responses if I use Stick contact between brackets (+crossmembers bolted) and long members while varying their location?


Hello, I have a laminate with 3 plies. I want to optimise the orientation of these plies such that the deflection of the laminate is minimum under the applied load. I can only perform composite shuffle, but I'm not able to optimise the ply angles. Please advice as to how to proceed to solve this issue Thanks, Kushal.
 17 replies

 optistruct
 composite

(and 1 more)
Tagged with:

Hello, If I am to put RBE3 in a hole (with no force or constraint attached to the dependant node) will this imply any stiffness to the voids outer surface where the independent nodes are? Or does the hole just remain as it would if it was a void with nothing in it? What type of 1D element could be used to provide a defined stiffness to the outer surface of a hole? Thank you in advance

Hello, I am running a topology optimisation using Optistruct. I am trying to look at the key structural members of an aerospace component. I am attempting to use a low volume fraction of ~36%. When the volume fraction is particularly low does this effect the solver's ability to converge? Thank you in advance

Hello Everyone, I am trying to do thermo structural analysis in optistruct. later I have to continue optimisation on structural analysis. Basically thermal expansions are only load for my optimization problem. I faced following difficulties and trying to resolve them, 1. thermo structural analysis in optistruct  I have referred all tutorial and discussion available a I did find any direct method to read temperature from my thermal analysis and apply it as load in structural analysis. I have pipe carrying hot fluid and I have convection heat loss so direct TEMP use in static is not possible for me and off course I have referred Coupled Linear Heat Transfer/Structure Analysis , however problem is I need to use structural subcase id as reference to my optimization so I cant use CASE_UNSUPPORTED_CARDS control card. 2. How to request temperature output in static analysis some how if I am able to run structural run with TEMP in static analysis, I will have to compare my temperature contour. So how can I request thermal output in static analysis results. (already have tried loadstep> edit>OUTPUT>THERMAL. didnt work) 3. How can I use DRESP2 in optimization, already have found one discussion on same but corresponding tut link is expired. Basically I want to use relative displacement in my optimization as constraint. Thank you
 3 replies

 optistruct
 thermostructural

(and 2 more)
Tagged with:

Hello I am trying to run an Optistruct optimisation but I get the following errors: *** ERROR # 157 *** Error opening the scratch file "./Analyse4_8584_s44.rs~" Fortran error code = 9 This may be caused by not having the access right to open the file, not enough memory left for the system routines, or some other system setup related reasons. This error was detected in subroutine opseqscr. *** ERROR # 158 *** Error encountered when accessing the scratch file. error from subroutine "xdslrs" Solver error no. = 702 This may be caused by insufficient disk space or some other system resource related limitations. This error was detected in subroutine bcsprefct. This error occurs in module "lstatdrv". *** FATAL ERROR # 8012 *** Data block kauspc is already inserted. * DATAMANAGER ERROR in subroutine "datami". PROGRAM STOPPED DUE TO ERROR. The constraint is a static stress called in the design variable. The objective is to minimize mass. The check only gives me such a warning: *** WARNING # 1848 Topology Optimization without Minimum Member Size Control activated. Using DTPL card, or DOPTPRM,MINDIM is recommended. Anybody has a clue of what is the problem? I'm a bit stuck here! Cheers
 6 replies

 Optistruct
 Optimisation

(and 4 more)
Tagged with:

Dear all, Is there a way to automatically run OSSmooth and reanalysis with optistruct. Basically up to now we are running an optimisation then going to hypermesh, running OSSmooth, and rerunning optistruct to see what deflection we get with the optimised shape.\ Can we set that at once (maybe as a batch process) so we don't have to do the whole thing, and get optimisation + Reanalysis at once? Many thanks.
 6 replies

 optistruct
 optimisation

(and 1 more)
Tagged with:

Attached is a Hypermesh deck of a structure whose mass I’m trying to minimize. The structure has a square shaped core covered on the top and bottom by composite facesheets. Shell elements have been used for modeling. The size of the square and the thickness of its wall determine the buckling characteristics of the facesheets. I’ve modeled using a square of side 6mm and its wall thickness is 1.5 mm (shown in the snapshot below). By varying the size of this square and changing the wall thickness, I’m looking to minimse the mass, the constraint being that the buckling factor must always be greater than 1. Could you please help me achieve my objective? Thanks, Kushal Agarwal. square_foam_opti.hm
 16 replies

 optimisation
 optistruct

(and 5 more)
Tagged with:

Hi, Does anyone have any tips on how to go about optimising the internal structure of an aircraft wing? I am a very new user to Hypermesh. Thanks.

Sir, I have a query on how to create "<name>. radopt " file in radios for optimisation problem stated in example 51 of b pillar optimisation in radioss and also where i should specify the design variables, constraints and objectives in radioss like /DESOBJ, /DESVAR etc cards in RADIOSS. Anticipating for quick and clear response as it is very urgent.
 2 replies

 multidomain
 radioss

(and 1 more)
Tagged with:

Hi All, Please find attached tutorial for CFD optimisation of a manifold. Some of the applications, where it can be used includes, HVAC ducting • Reduce pressure drop • Increase flow uniformity • Maximize/minimize outlet temperature Heat exchangers • Maximize pressure drop • Maximize heat transfer Brake discs • Minimize temperature • Maximize heat transfer • Brake cooling ducts External Aero • Minimize drag • Maximize negative lift and many more. I have also attached a simple Pipe CFD optimisation tutorial. Please do contact us for any queries. Regards, kamlesh Acusolve_Hyperstudy_tutorial_manifold.zip Acusolve_Hyperstudy_Tutorial_Pipe.zip

 optimisation
 hypermorph

(and 3 more)
Tagged with:

I am not able to decide what design responses I need to take? Should I take displacement or stresses? I am having problem in deciding upper and lower bound of those responses.

Topography optimisation of a single ply in a 2 ply composite laminate
Kushgen posted a topic in OptiStruct
Attached are 2 Hypermesh models. The Aim is to minimize mass. I have used 2 composite plies to model the structure. 2 PCOMPG properties have been assigned to the plies respectively. Only 1 out of these 2 plies needs to be optimized topographically to obtain stiffener patterns. The other ply must continue to remain in its original shape In the “volume_feasible.hm” file , I have minimized volume as the objective. The optimization run gives a feasible design. However, when I check the results, there is no change in the shape of the ply and no bead patterns are obtained. Next, I changed the objective to minimize mass just to see if I get the desired result. Again, I obtain a feasible design but there is no change in the shape of the ply and no bead patterns are obtained. In this model, no contact has been defined between the plies. In the “stick_contact.hm” file, I’ve defined a stick contact between the two plies and run the optimization. Here again, I obtain a feasible design but there are no bead patterns obtained in the result. if anyone has tried a similar problem before please help me out. stick_contact.hm volume_feasible.hm 6 replies

 optistruct
 optimisation
 (and 4 more)

Submitted by Enric on Wed, 05/25/2011  15:11 I had a question regarding a model which I am trying to create: please note I am quite new to Vissim. I am trying to model the level of a solute in the blood using a masstransfer model. The model is defined by a number of compartments, with mass flow occurring between them and a number of integration functions, plus "unknown" constants which define the rates of mass flows between compartments. To create the model I have guessed these “unknown” constants and now the model is up and running. What I want to do is to “optimise” these constants to produce a model where the blood level most closely matches real, measured, values. Please could you give me some guidance on this. I have two initial questions: Obviously there a variable called “time” which ticks upwards as the model progresses. How can I access this variable to display another variable at a set time point (to compare to my actual values). ie. An operator which would allow the following function: WHEN time=x1 seconds, THEN display variable X. When time=x2 seconds, THEN display variable X. If I could do this, then I could perform the most simple form of optimisation by comparing variables visually ! In addition, being able to do this would give me a set of readings at set time points which I could use for optimisation. In my relatively simple model, which produces in the end a single output (solute concentration), how can I devise a system that optimises the solute concentration curve against actual measured levels that I have at discrete time points ? I am not sure if I should be using the Cost function here. Any guidance on this would be appreciated and thanks. I'm not after someone doing the model for me, its more that I'm still getting to grips with what functions are available for this.

Hello, as suggested in another thread in this Forum, i tried the usage of dresp3Card. What i want to do:  let excel calculate the trescastress (Input: max principle, min principle, output: stress (=difference between both input variables).  get the tresca stress back and use it for an "minmax" or "minobjective" in optimisation What i wrote until today: LOADLIB DRESP3 GR01 tresca.xlsx $solid DRESP1 1 MAX_PR1 STRESS PSOLID SMAP DRESP1 1 MAX_PR3 STRESS PSOLID SMIP DRESP3 20 TRESCA GR01 MYFUNC 1 2 + DRESP1 1 2 + CELLIN C2 C3 + CELOUT D1 I also use a small excelfile, which calculates the difference beween "cell C2" and "cell C3" in "cell D1". Questions:  would it work like that ? (I can't test it at the moment)  What do I get with the DRESP1 / DRESP3 ? When using DRESP1 with "ELEM" and enter an elementID, it would give ONE value to the excelfile, which seems to be pretty clear. But when I use PSOLID as the PTYPE, there might be hundrets or thousands of values (here: principal stresses). At that point I do not understand my own programmed code.. Maybe someone can help? I read the Tutorial OS4095 and also a lot of manual pages. Thanks a lot

Hi, I was using the lattice optimisation tutorial in order to complete a lattice optimisation on my own component and it completed the first step no problem, producing the "_lattice.fem" file. However, when I then ran that through OptiStruct, I got the following error: *** ERROR # 1814 *** MASSFRAC response on DRESP1 card 2 is not applied to a topology or freesize domain. Please could you advise on what I should do? Kind Regards, Iain
 1 reply

 optistruct
 lattice

(and 2 more)
Tagged with:

I am doing the shape optimisation and I am getting the responce error. H:/New folder (2)/Opti/sh2.fem "DSYSID 1 Shapeopt" *** ERROR # 1000 *** in the input data: Incorrect data in field # 4. I have given the responce from... responses>response name> response type = static stress> Prop(select components,inlet,outlet,wall)> create. But its not working.

Hi, I am doing the simple optimisation, which has inlet at one side and outlet on other. I have done CFD tetra mesh and want to perform a free shape optimisation. I am getting the error on running the solver. I have attached the screenshot.

I want to optimisation in pipes of different diameters connected to each other. What boundary condition (like loads and constraints) I can input. If I only want to see topology optimisation.

Hello Group I wanted to know whether its is possible to define output as a constraint in optimisation. I am validating my modell with frequency response test I want to vary values of Material properties like Emodulus, G modulus so that at certain frequencies Frequency Response Function FRF (velocity) is say (+\ 10 % ) of the FRF calculated by test. eg Vary values of E = 1000 mpa to 2000 mpa G= 200 mpa to 400 mpa so that at node 256 Frq frf (test) frf(simulation) 5hz 0.256 (+/ 0.01) of 0.256 10hz 0.586 (+ 0.01) of 0.586 15 hz 1.457 (+ 0.01) of 1.457 etc Is it possible to define constraint this way a suggestion or example tutorial would be quit helpful Thanks and Regards Pratik
 1 reply

 constraint
 optistruct

(and 1 more)
Tagged with:

Shuffling phase in composite optimisation of a formula student monocoque
tobyd111 posted a topic in OptiStruct
Hi, I am currently trying to do composite optimisation of a carbon fibre sandwich structure monocoque. I have been following the "composite optimisation of a formula student monocoque" tutorial on the Altair university training website and am up to the shuffling stage however am not getting any results and getting this message: *** WARNING # 1569 for element id = 70001. Thickness is zero for this composite. This will produce meaningless stress results and may cause singularity of the global stiffness matrix. *** WARNING # 1569 for element id = 70002. Thickness is zero for this composite. This will produce meaningless stress results and may cause singularity of the global stiffness matrix. *** WARNING # 1569 for element id = 70003. Thickness is zero for this composite. This will produce meaningless stress results and may cause singularity of the global stiffness matrix. *** WARNING # 1569 for element id = 70004. Thickness is zero for this composite. This will produce meaningless stress results and may cause singularity of the global stiffness matrix. *** WARNING # 1569 for element id = 70005. Thickness is zero for this composite. This will produce meaningless stress results and may cause singularity of the global stiffness matrix. *** WARNING # 1569 for element id = 70006. Thickness is zero for this composite. This will produce meaningless stress results and may cause singularity of the global stiffness matrix. *** WARNING # 1569 for element id = 70007. Thickness is zero for this composite. This will produce meaningless stress results and may cause singularity of the global stiffness matrix. *** WARNING # 1569 for element id = 70008. Thickness is zero for this composite. This will produce meaningless stress results and may cause singularity of the global stiffness matrix. *** WARNING # 1569 for element id = 70009. Thickness is zero for this composite. This will produce meaningless stress results and may cause singularity of the global stiffness matrix. *** WARNING # 1569 for element id = 70010. Thickness is zero for this composite. This will produce meaningless stress results and may cause singularity of the global stiffness matrix. *** More of WARNING messages # 1569 were suppressed... thanks in advance for any advice. Toby 2 replies

 monocoque
 zero thickness

(and 2 more)
Tagged with: