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fe_simul

Purpose

High level access to standard solvers.

Syntax

 [Result,model] = fe_simul('Command',MODEL,OPT)

Description

fe_simul is the generic function to compute various types of response. It allows an easy access to specialized functions to compute static, modal (see fe_eig) and transient (see fe_time) response. A tutorial may be found in section 4.4.

Once you have defined a FEM model (section 4.2), material and elements properties (section 4.2.1), loads and boundary conditions (section 4.2.3), calling fe_simul assembles the model (if necessary) and computes the response using the dedicated algorithm.

Note that you may access to the fe_simul commands graphically with the simulate tab of the feplot GUI. See tutorial (section 4.4) on how to compute a response.

Input arguments are :

• MODEL a standard FEM model data structure with loads, boundary contions, ... defined in the case. See section 4.2 (tutorial), fe_case for boundary conditions, fe_load for loads, ...
• OPT is an option vector or data structure used for some solutions. These may also be stored as model.Stack entries.

Accepted commands are

• Static: computes the static response to loads defined in the Case. no options are available for this command

   model = demosdt('demo ubeam');cf=feplot;cf.model=model;
   data  = struct('sel','GroupAll','dir',[1 0 0]);
   model = fe_case(model,'FVol','Volume load',data);
   [cf.def,model]=fe_simul('static',model);
  

• Mode : computes normal modes, fe_eig options can be given in the command string or as an additional argument. For modal computations, opt=[method nm Shift Print Thres] (it is the same vector option as for fe_eig). This an example to compute the first 10 modes of a 3D beam :

    model = demosdt('demo ubeam');cf=feplot;cf.model=model;
    model=stack_set(model,'info','EigOpt',[6 10 0 11]);
    [cf.def,model]=fe_simul('mode',model);
   

• DFRF: computes the direct response to a set of input/ouput at the frequencies defines in Stack.

   femesh('reset'); model = femesh('testubeamt');
   model=fe_case(model,'FixDof','Clamped end','z==0');
   r1=struct('DOF',365.03,'def',1.1); % 1.1 N at node 365 direction z 
   model=fe_case(model,'DofLoad','PointLoad',r1); 
   model= stack_set(model,'info','Freq',1:10);
   def=fe_simul('DFRF',model);
  

• Time : computes the time response. You must specify which algorithm is used (Newmark, Discontinuous Galerkin dg or Newton)). For transient computations, opt= [beta alpha t0 deltaT Nstep Nf] (it is the same vector option as for fe_time). Calling time response with fe_simul does not allow initial condition. This is an example of a 1D bar submitted to a step input :

    model=demosdt('demo bar');
    [def,model]=fe_simul('time newmark',model,[.25 .5 0 1e-4 50 10]);
    def.DOF=def.DOF+.02;
    cf=feplot;cf.model=model;cf.def=def;
    fecom(';view1;animtime;ch20');
  

See also

fe_eig, fe_time, fe_mk