R, C, I Power Calculations

R, C, I definitions

Resistive, Capacitive and Inertial elements are defined by the algebraic equations that set a relationship with the flux variable and effort variables and their derivatives:

With:

• algebraic function, not always linear;

• flux variable;

• effort variable.

Power, Energy and Activity

Based on the bond graph theory, the power of a Resistive, Capacitive or Inertial element is given by the product of the effort and the flux variables on the element bond graph arc:

With:

• for a Resistive element;

• for a Capacitive element;

• for an Inertial element;

• power [W].

This algebraic relation between the flux variable, the effort variable and their derivate identifies the physical type of the element (R, C, or I).

Given this power, the energy is defined as its integral value over time and the activity is the integral of the power absolute value. Energy and activity are explicit state variables in Simcenter Amesim. You can thus specify their initial values at the simulation start time t0 or obtain them from previous results using the Continuation run or the Use old final values option. These initial values are null by default and most of the time t0 = 0 [s].

With:

• energy dissipated in a Resistive element [J];

• energy stored in a Capacitive element [J];

• energy stored in an Inertial element [J].

With:

• activity of a Resistive element [J];

• activity of a Capacitive element [J];

• activity of an Inertial element [J].