Public Documentation

Main module for BongGraph.jl – a bond graph modeling toolkit based on ModelingToolkit.jl Julia package.

Exports

• Power
• Se
• Sf
• Dq
• Junction1
• Junction0
• mGY
• mTF
• Mass
• Spring
• Damper
• reducedobs
• isindependent
• generate_graph
• simplifysys

Imports

• Base
• Core
• DocStringExtensions
• DomainSets
• GraphRecipes
• ModelingToolkit
• Plots
• Reexport

License

The LICENSE abbreviation can be used in the same way for the LICENSE.md file.

Se(expr; name)

Creates a source of effort element in the bond graph model. TODO: Improve

Arguments:

• expr: Expression representing the source value.
• name: Name of the source element.

Returns:

An ODESystem representing the source element.

Example:

julia> @named s1 = Se(2.0)

Sf(expr; name)

Creates a source of flow in the bond graph model TODO: Improvess

Arguments:

• expr: Expression representing the flow source value.
• name: Name of the flow source element.

Returns:

An ODESystem representing the flow source element.

Example:

julia>  @named s2 = Sf(3.5)

Junction1(ps...; name="", couple=true)

Create a one-junction element in the bond graph model.

Arguments

• ps...: One or more elements to be connected to the one-junction.
• name::String: The name of the one-junction element (default: "").

Returns

An ODESystem representing the one-junction element in the bond graph model.

Remarks

• The ps argument accepts one or more elements to be connected to the one-junction.
• The function automatically determines the flow directions and subsystems based on the signs of the connections.

Examples

# Create a one-junction connecting multiple elements
julia> junction = Junction1(damper1, damper2, spring1, spring2, name="junction")

Junction0(ps...; name="", couple=true)

Create a zero-junction element in the bond graph model.

Arguments

• ps...: One or more elements to be connected to the zero-junction.
• name::String: The name of the zero-junction element (default: "").

Returns

An ODESystem representing the zero-junction element in the bond graph model.

Remarks

• The ps argument accepts one or more elements to be connected to the zero-junction.
• The function automatically determines the flow directions and subsystems based on the signs of the connections.

Examples

# Create a zero-junction connecting multiple elements
julia> junction = Junction0(damper1, damper2, spring1, spring2, name="junction")

mGY(subsys...; name="", g=1.0, coneqs=[])

Create a gyrator element in the bond graph model.

Arguments

• subsys...: One or more subsystems to be connected to the gyrator.
• name::String: The name of the gyrator element (default: "").
• g::Number|Symbol: A value or a expression representing the gyrator relationship (default: 1.0).
• coneqs::Vector{Equation}: Additional output connection equations of the modulated gyrator (default: []).

Returns

An ODESystem representing the gyrator element in the bond graph model.

Examples

# Create a gyrator with a variable value
@variables c
julia> gyrator = mGY(subsys1, subsys2, g=c, name="gyrator")

mTF(subsys...; name="", r=1.0, coneqs=[])

Create a transformer element in the bond graph model.

Arguments

• subsys...: One or more subsystems to be connected to the transformer.
• name::String: The name of the transformer element (default: "").
• r::Number|Symbol: A value or a expression representing the transformer relationship (default: 1.0).
• coneqs::Vector{Equation}: Additional output connection equations of the modulated gyrator (default: []).

Returns

An ODESystem representing the transformer element in the bond graph model.

Examples

# Create a transformer with a variable value
@variables c
julia> transformer = mTF(subsys1, subsys2, g=c, name="transformer")

Mass(; name="", m=1.0, u=0.0)

Create a mass element in the bond graph model.

Arguments

• name::String: The name of the mass element (default: "").
• m::Float64: The mass value (default: 1.0).
• u::Float64: The initial value for the flow variable (default: 0.0).

Returns

An ODESystem representing the mass element in the bond graph model.

Examples

julia> mass = Mass(name="my_mass", m=2.0, u=1.0)

Spring(; name="", k=10, x=0.0)

Create a spring element in the bond graph model.

Arguments

• name::String: The name of the spring element (default: "").
• k::Float64: The spring stiffness (default: 10).
• x::Float64: The initial displacement (default: 0.0).

Returns

An ODESystem representing the spring element in the bond graph model.

Examples

julia> spring = Spring(name="my_spring", k=5.0, x=0.1)

Damper(; name="", c=10, u=1.0)

Create a damper element in the bond graph model.

Arguments

• name::String: The name of the damper element (default: "").
• c::Float64: The damping coefficient (default: 10).
• u::Float64: The initial flow variable value (default: 1.0).

Returns

An ODESystem representing the damper element in the bond graph model.

Examples

julia> damper = Damper(name="my_damper", c=5.0, u=0.1)

generate_graph(mdl, var=:e; method=:stress)

Generates a graph visualization of the bond graph model.

Arguments:

• mdl: Bond graph model.
• var: Variable to visualize connections for. Can be :e (effort) or :f (flow). Default is :e.
• method: Graph layout method. Default is :stress.

Example:

julia> generate_graph(mdl, var=:e, method=:stress)

simplifysys(sys::ODESystem; name)

Simplify an ODE system by expanding connections, performing structural simplification and reducing the observed variables.

Arguments:

• sys::ODESystem: The ODE system to simplify.
• name: Optional name for the simplified system.

Returns:

• The simplified ODE system.

isindependent(var::Num)

Check if a variable is independent.

Arguments:

• var::Num: The variable to check.

Returns:

• true if the variable is independent.
• false if the variable is not independent.