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getting_started

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getting_started [2017/10/11 15:18]
marijn.nijenhuis ↷ Links adapted because of a move operation 		getting_started [2017/10/18 12:08] (current)
marijn.nijenhuis [References]
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 In general, a multibody model is a collection of bodies that are interconnected. Such a model typically represents a mechanism, a linkage or a structure. The bodies could be fully rigid, or have some flexibility. The points of interconnection typically represent the joints (revolute joint, spherical joint, etc.) or contact points of the system.  In general, a multibody model is a collection of bodies that are interconnected. Such a model typically represents a mechanism, a linkage or a structure. The bodies could be fully rigid, or have some flexibility. The points of interconnection typically represent the joints (revolute joint, spherical joint, etc.) or contact points of the system. 
  
-[examples]+|  {{:staubli.jpg?nolink&200}}  |  {{:generalmultibody.png?nolink&400}}  | 
 +|  //Example of a serial robot arm [1]//  |  //Schematic multibody model [2]//  | 
  
 With a description of the geometry of the bodies, the material properties, and some kind of input to the model, the behavior of the entire multibody model can be simulated. This way, the actual system that the multibody model represents can be analyzed in terms of e.g.  With a description of the geometry of the bodies, the material properties, and some kind of input to the model, the behavior of the entire multibody model can be simulated. This way, the actual system that the multibody model represents can be analyzed in terms of e.g. 
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   * natural frequencies and buckling loads, and   * natural frequencies and buckling loads, and
   * fully time-dependent dynamic behavior.   * fully time-dependent dynamic behavior.
- 
 ==== Elements and nodes ==== ==== Elements and nodes ====
 In SPACAR (as in most other finite element and multibody software), the bodies are usually referred to as //elements//, and the points of interconnection as //nodes//. The full version of SPACAR features a range of different elements for modeling a variety of systems. While powerful, this does increase the complexity of creating a model. In SPACAR (as in most other finite element and multibody software), the bodies are usually referred to as //elements//, and the points of interconnection as //nodes//. The full version of SPACAR features a range of different elements for modeling a variety of systems. While powerful, this does increase the complexity of creating a model.
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 In SPACAR Light, we're only considering one type of element: the 3-D flexible beam element. Also, the type of analysis is only going to be static (including natural frequencies and buckling loads). Both choices are well suited to the analysis of flexure mechanisms and reduce complexity for the user. In SPACAR Light, we're only considering one type of element: the 3-D flexible beam element. Also, the type of analysis is only going to be static (including natural frequencies and buckling loads). Both choices are well suited to the analysis of flexure mechanisms and reduce complexity for the user.
  
-[example of flexure mechanism turned multibody model] +|  {{::img_2971.jpg?nolink&200|}}  |  {{:spavisual.png?nolink&200|}}  |  {{:paral-draw.png?nolink&200|}}  | 
 +|  //Parallel flexure mechanism//  |  //Drawing//  |  //Schematic multibody model//  |
 ==== General usage ==== ==== General usage ====
-When SPACAR Light in installed correctly, it is typically invoked using the MATLAB command+When SPACAR Light is installed correctly, it is typically invoked using the MATLAB command
 <code matlab> <code matlab>
-out = spacarlight(nodes,elements,nprops,eprops,rls)+out = spacarlight(nodes,elements,nprops,eprops)
 </code> </code>
-With the basic concept of a multibody model outlined above, this command is already very revealing; it shows that the user has to provide five inputs:+With the basic concept of a multibody model outlined above, this command is already very revealing; it shows that the user has to provide four inputs:
  
   - Coordinates of the nodes in ''nodes''   - Coordinates of the nodes in ''nodes''
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   - Node properties (such as boundary conditions, applied loads and inertia) in ''nprops''   - Node properties (such as boundary conditions, applied loads and inertia) in ''nprops''
   - Sets of element properties (such as dimensions, material constants and flexibility) in ''eprops''   - Sets of element properties (such as dimensions, material constants and flexibility) in ''eprops''
-  - 'Releases' to deal with overconstrained (statically indeterminate) systems in ''rls'' 
  
-The first four inputs are typically fairly self-evident. It is only the fifth ''rls'' input that can be confusing for beginning users (because the solution to overconstraints is not obvious). There is a separate page on dealing with the ''rls'' input.+Generally, these input argument are straight-forward. On the following pages, each input will be detailed. There is a [[walkthrough|walkthrough example]] in which all steps towards a simulation are explained. For complete reference, the [[full_syntax|full syntax list]] provides details of each field and property. Additional [[spacar_light_examples|examples]] of models are also available. 
 + 
 +==== References ==== 
 +//1: figure from staubli.com (Stäubli TX2-90 Product leaflet)//
  
-On the following pages, each input will be detailed. There is a [[walkthrough|walkthrough example]] in which all steps towards a simulation are explained. For complete reference, the [[full_syntax|full syntax list]] provides details of each command. Additional [[spacar_light_examples|examples]] of models are also available.+//2: figure from lecture slides Dynamics of Machines, J.B. Jonker, R.G.K.M. Aarts//
getting_started.1507727900.txt.gz · Last modified: 2017/10/11 15:18 by marijn.nijenhuis

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