﻿ 20-sim webhelp > Library > Iconic Diagrams > Mechanical > Translation > Components > mass

mass

Library

Iconic Diagrams\Mechanical\Translation\Components

Use

Domains: Continuous. Size: 1-D. Kind: Iconic Diagrams (Translation).

Description-Default

This model represents an ideal mass (no gravity). The element has a preferred velocity out causality. The corresponding constitutive equations then contain an integration. The element can also have the non-preferred force out causality. The constitutive equations then contain a derivation. Because any number of connections can be made, successive ports are named p1, p2, p3 etc. 20-sim will automatically create equations such that the resulting force p.F is equal to the sum of the forces of all connected ports p1 .. pn. The velocities of all connected ports are equal to p.v.

p.F = sum(p1.F, p2.F, ....)

p.v = p1.v = p2.v = ....

velocity out causality (preferred):

a = p.F/m;

p.v = int(a);

x = int(p.omega);

force out causality:

a = ddt(p.v);

p.T = m*a;

x = int(p.v);

Description-Gravity

This model represents an ideal mass with gravity. It is equal to the default model with a gravitational acceleration g added:

a = p.F/m - g;

p.v = int(a);

x = int(p.omega);

The gravitational acceleration g acts in the negative direction. E.g. a free fall will give the model a negative acceleration, negative velocity and negative position.

Interface

Ports

Description

p[any]

Any number of connections can be made (Translation).

Causality

preferred velocity out

An torque out causality results in a derivative constitutive equation.

Variables

x

a

p

position [m]

acceleration [m/s^2]

impulse [Ns]

Parameters

m

g

mass [kg]

acceleration of gravity [m/s^2]

Initial Values

p.v_initial

x_initial

The initial velocity of the mass.

The initial position of the mass.