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System Simulation

 
Using System Simulation to accelerate development and optimize designs

Content:

1. In respect to System Simulation, what is a system?
2. What is System Simulation?
3. Positioning of System Simulation in the CAD and CAE world
4. LMS Imagine.Lab AMESim, the leading platform for multi-physics system simulation

1. In respect to system simulation, what is a system?

By definition, a system is an organized, purposeful structure regarded as a ’whole’ consisting of interrelated and interdependent elements (components, entities, factors, members, parts etc.). These elements continually influence one another to maintain their activity and the existence of the system, in order to achieve the common purpose the ’goal’ of the systems.

All systems:

  • have inputs, outputs, and feedback mechanisms,
  • maintain an internal steady-state (called homeostasis) despite a changing external environment
  • display properties that are peculiar to the whole (called emergent properties) but are not possessed by any of the individual elements, and
  • have boundaries that are usually defined by the system observer.
Every system is a part of a larger system, is composed of sub-systems, and shares common properties with other systems that help in transferring understanding and solutions from one system to another.
 
System examples:

Electro-hydraulic power steering system

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Electro-hydraulic power steering systems, sometimes abbreviated EHPS, use the same hydraulic assist technology as standard systems, but the hydraulic pressure is provided by a pump driven by an electric motor instead of being belt-driven by the engine. 

Power steering reduces the steering effort on vehicles by using an external power source to assist in turning the road wheels. In this case, the external power source is the fluid power generated by the engine. This system consists of several physical parts: a mechanical steering column gives an input to an electro-hydraulic converter that can drive the road wheels which are then mechanically actuated. Everything is driven by an electronic control unit that controls the speed and gives orders to the electro-hydraulic system, in order to prevent the steering system to react to fast at high engine speed. This example illustrates the different aspects of physics that are interacting together: hydraulic, electric and mechanical. Mechanical energy transformed into hydraulic energy, then electric controls influence the behavior of the hydraulic system, then hydraulic energy is finally transformed into mechanical energy to actuate the road wheels. These are the main domains we are working through with system simulation.
 
Washing machine

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A washing machine contains mechanical elements that make the system run, an hydraulic system that provides the water to the laundry, a thermal system that controls the temperature level and the electronic controls that manages the whole cycle. So here again we can easily state that this system is multi-physical. 


2. What is System Simulation?

System simulation is the simulation of multi-physics models, for transient analysis purposes, based on power exchanges that can be started at pre-design and specification stages, with a reduced number of parameters.

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System simulation is most likely based on equations dependant of time (ODE, DAE). System simulation is linked to power flow within a system, which can be addressed by the following questions: where power goes? Where power is lost? Where power is created? Where power is exchanged?
It is important to add that system simulation is also linked to the control of this power, more precisely system simulation is most of the time in close relations with automation and control, and strongly linked to electronics as well. This integration with controls and electronics leads to the study of mechatronics, meaning the behavior of intelligent systems.
System simulation does not use full 3D based geometry, but requires as input a reduced number of parameters used to describe the system to be analyzed and modeled.
 
3. Positioning of System Simulation in the CAD and CAE world

Most of the software tools used in the industry are based on exchanges of CAD files parameters. CAD (Computer Aided Design), CAE (Computer-Aided Engineering), CFD (Computational Fluid Dynamics), Finite Elements and Multi-body softwares are all linked to the exchange of 3D parameters. The system simulation is not really fully integrated into the same process of directly integrating CAD data, but most of the parameters are simply given by tables and results of experiments. We can state that system simulation acts as an essential complement of all the CAD chain for studying dynamic behavior of systems.
System simulation is emerging as a modern way of simulating complex systems with multiple sub-elements and different physics to be represented at the same time. As mentioned above, system simulation is linked to power systems where energy is created, used, or transformed. It has a strong link with electronic control development as it represents the systems to be controlled.

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Moreover, LMS also positions the software in the physical domains, so the platform we have is a multi-physics platform, taking into account many physical phenomena like hydraulics, pneumatics, thermal, electronics, controls, mechanics, etc. Studying all these physical domains requires gates to existing other softwares to get input parameters, from Multi-body Systems, CFD Analysis, Magnetic, Finite Elements, Control Algorythm Proceeding Tools, etc.




























 
4. LMS Imagine.Lab AMESim, the leading platform for multi-physics system simulation
 
We can introduce the LMS Imagine.Lab AMESim platform as a system simulation platform, based on a set of physical libraries developed with IP from industry expertise. As system simulation is supposed to be based on mathematical computation, AMESim provided a strong solver and numerical core for transient simulation. As modeling a complex multi-physics system is not the main objective of engineers, it is really important to have tools and interfaces accelerate and optimize the design. AMESim is a complete software suite for model creation and deployment, all over the company.
 
 
 
 
 
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