simulation single_run transient
Enables Adams View to perform either a:
■Kinematic simulation if your model has zero degrees of freedom.
■Dynamic simulation if your model has one or more degrees of freedom.
Format:
simulation single_run transient |
|---|
model_name = | existing model name |
initial_static = | boolean |
type = | DYNAMIC/ KINEMATIC/ STATIC/ AUTO_SELECT |
number_of_steps = | integer |
step_size = | real |
end_time = | real |
duration = | real |
forever = | true |
Example:
simulation single_run transient & |
|---|
model_name = | MODEL_1 & |
initial_static = | no & |
type = | DYNAMIC & |
number_of_steps = | 50 & |
end_time = | 1 |
In the above example, specifying 50 steps over a one-second simulation interval will define an output period of 0.02 seconds per step, which yields an output frequency of 50 steps/second.
Description:
Parameter | Value Type | Description |
|---|
model_name | Existing Model | Specifies an existing model. |
initial_static | Yes/no | Specifies whether or not Adams is to execute a static solution prior to the main simulation. |
type | Dynamic/ Kinematic/ Static/ Auto_select | Select a type of simulation to run: ■Dynamic ■Kinematic ■Static ■Auto_select |
number_of_steps | Integer | Represents the total number of times you want Adams View to provide output information over your entire simulation |
step_size | Real | Represents the amount of time, in current model units, between output steps. |
end_time | Real | Specifies the absolute point in time at which you want the simulation to stop. |
duration | Real | Specifies the amount of time over which you want the simulation to run. The DURATION must be greater than zero. |
forever | True | Boolean value specifying whether or not the simulation has to run forever. |
Extended Definition:
1. You may identify a model by typing its name or by picking it from the screen.
If the model is not visible on the screen, you must type the name. You may also find it convenient to type the name even if the model is displayed.
You must separate multiple model names by commas.
If the model is visible in one of your views, you may identify it by picking on any of the graphics associated with it.
You need not separate multiple model picks by commas.
2. If you select YES for the initial_static parameter, Adams will run a static analysis before starting the simulation you have specified with the ANALYSIS_TYPE, NUMBER_OF_STEPS, and END_TIME parameters.
You may wish to set this parameter to YES when running a vehicle model, for instance, to allow the vehicle to settle on its suspension before starting a transient analysis.
3. For the step_size parameter, the output frequency remains constant even if you change your simulation end time or duration. For example, enter a step size of 0.01 seconds to specify an output period of 0.01 seconds per step, which yields an output frequency of 100 steps/second.
4. You can run five types of simulations in Adams View:
■Dynamic - A time-history solution for all displacements, velocities, accelerations, and internal reaction forces in your model driven by a set of external forces and excitations. A dynamic simulation is also known as a kinetic simulation.
During a dynamic simulation, Adams Solver solves the full set of non linear differential and algebraic equations (DAEs). It is the most complex and computationally demanding type of simulation and is meant to be used with models that have one or more degrees of freedom.
A dynamic simulation provides a time-history solution for displacements, velocities, accelerations, and internal reaction forces in your model driven by a set of external forces and excitations.
■Kinematic - Determines the range of values for the displacement, velocity, and acceleration of any point of interest in the model, independent of forces applied to it. During a kinematic simulation, Adams Solver solves only the reduced set of algebraic equations. This type of simulation, therefore, is only available for models with zero degrees of freedom.
If you specify the mass and inertial properties of bodies in your model, a kinematic simulation also calculates the corresponding applied and reaction forces required to generate the prescribed motions.
■Static - Finds the state of the model in which all internal and external forces are balanced in the absence of any system motions or inertial forces. It sets all system velocities and accelerations to zero, so inertial forces are not taken into consideration. A static simulation is for use with models that have one or more degrees of freedom so Adams Solver can move parts around as it seeks to balance all the forces acting on the model.
You can request to perform a static equilibrium before a dynamic simulation to remove unwanted system transients at the start of the simulation. (Unbalanced forces in the initial configuration can generate undesirable effects at the beginning of a dynamic analysis).
■Initial conditions - An initial conditions simulation ensures the proper assembly of your model before other simulations. It checks to ensure that all constraints and initial conditions are allowable and consistent. If it finds any discrepancies, it corrects them so that there is a consistent set of values representing the state of the model and assembles the model in a more appropriate way.
For example, if initial values for displacements and velocities violate the constraint equations, Adams Solver modifies the input displacement and velocity data to satisfy the constraint equations while minimizing the change in the input data.
■Linear Linearizes your nonlinear dynamic equations of motion about a particular operating point in order to determine natural frequencies and corresponding mode shapes. You must purchase Adams Linear to perform a linear simulation.
5. END_TIME must be greater than the begin time.
Since the begin time must be greater than zero, this means that the end time must also be greater that zero.
6. For the “forever” parameter, Adams View continues simulating until you stop the simulation or until it can no longer solve the equations of motion within your specified tolerance.
If this option is selected, then specify step size and not number of steps in the parameters above.