31. SIMULATION
Some complex systems can't be modeled because of,
- changing operating conditions
- exact solutions don't exist
Simulation is used to determine how these systems will behave
Simulation typically involves developing a model that includes discrete stations and events that occur with some probable distribution.
We can then examine the simulation results to evaluate the modeled system. Examples include,
This is a very effective tool when considering the effect of a change, comparing decision options, or refining a design.
Some simulation terms include,
System - the real collection of components
Model - a reasonable mathematically (simpler) representation of the system
State - the model undergoes discrete changes. A state is a `snapshot' of the system
Entity - a part of the system (eg machine tool)
Attributes - the behavior of an entity
Event - something that changes the state of a machine
Activity - when an entity is going through some activity. (eg, press cycling)
Delay - a period of time with no activity
Good approach to simulation,
1. Determine what the problem is
2. Set objectives for the simulation
3. Build a model and collect data
4. Enter the model into a simulation package
5. Verify the model then check for validity
6. Design experiments to achieve goals
7. Run simulations and collect results
8. Analyze and make decisions
