Spring constraint between two particles. More...

#include <Spring.hpp>

Collaboration diagram for Phyth::Mechanics::Spring:

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Public Member Functions
	Spring (std::shared_ptr< Particle > p1, std::shared_ptr< Particle > p2, const Quantity< NewtonPerMeter > &stiffness, const Quantity< KilogramPerSecond > &damping=Quantity< KilogramPerSecond >{0})
	Construct a spring between two particles.

void	Constrain () const
	Apply spring and damping forces to both particles (Force Constrain)

const std::shared_ptr< Particle > &	GetParticle1 () const

const std::shared_ptr< Particle > &	GetParticle2 () const

const Quantity< Meter > &	GetRestLength () const

const Quantity< NewtonPerMeter > &	GetStiffness () const

const Quantity< KilogramPerSecond > &	GetDamping () const

Quantity< Meter >	GetCurrentLength () const

Quantity< Meter >	GetElongation () const

void	SetRestLength (const Quantity< Meter > &rest_length)
	Set a new rest length.

void	SetStiffness (const Quantity< NewtonPerMeter > &stiffness)
	Set a new stiffness.

void	SetDamping (const Quantity< KilogramPerSecond > &damping)
	Set a new damping coefficient.

Quantity< Joule >	GetElasticEnergy () const
	Compute the elastic potential energy stored in the spring.

Quantity< Newton >	GetEnergyDensity () const
	Compute energy per unit length.

Static Private Member Functions
static void	validateRestLength (const Quantity< Meter > &length)

static void	validateStiffness (const Quantity< NewtonPerMeter > &stiffness)

static void	validateDamping (const Quantity< KilogramPerSecond > &damping)

Private Attributes
std::shared_ptr< Particle >	p1_

std::shared_ptr< Particle >	p2_

Quantity< NewtonPerMeter >	stiffness_

Quantity< KilogramPerSecond >	damping_

Quantity< Meter >	rest_length_

Detailed Description

Spring constraint between two particles.

Spring applies a Hooke's law force between two particles: F = -k * (current_length - rest_length) * direction

Additionally, a damping force proportional to the relative velocity along the spring axis can be added: F_damp = -c * (v1 - v2) · direction

The spring is bi-directional: equal and opposite forces are applied to both particles. If one particle is fixed, the other still moves correctly.

Example: auto p1 = std::make_shared<Particle>(1_kg, Vector3{0_m, 0_m, 0_m}); auto p2 = std::make_shared<Particle>(1_kg, Vector3{1_m, 0_m, 0_m});

Spring spring(p1, p2, 10.0_N/m, 0.5_kgps);

// In simulation loop: spring.Constrain();

auto energy = spring.GetElasticEnergy(); // 1/2 * k * elongation^2

Definition at line 37 of file Spring.hpp.

Constructor & Destructor Documentation

◆ Spring()

Phyth::Mechanics::Spring::Spring	(	std::shared_ptr< Particle >	p1,
		std::shared_ptr< Particle >	p2,
		const Quantity< NewtonPerMeter > &	stiffness,
		const Quantity< KilogramPerSecond > &	damping = `Quantity<KilogramPerSecond>{0}`
	)

inline

Construct a spring between two particles.

Parameters

p1	First particle (force applied in direction p2->p1)
p2	Second particle (force applied in direction p1->p2)
stiffness	Spring constant k (N/m)
damping	Damping coefficient c (kg/s), default 0

The rest length is automatically set to the initial distance between the two particles.

Exceptions

std::invalid_argument If rest length <= 0, stiffness < 0, or damping < 0

Definition at line 53 of file Spring.hpp.

Member Function Documentation

◆ Constrain()

void Phyth::Mechanics::Spring::Constrain ( ) const

inline

Apply spring and damping forces to both particles (Force Constrain)

The spring force is: F = k * (current_length - rest_length) * direction

If damping > 0, an additional damping force is applied: F_damp = c * (v1 - v2) · direction

Both forces are applied in opposite directions to p1 and p2.

Definition at line 76 of file Spring.hpp.

◆ GetCurrentLength()

Quantity< Meter > Phyth::Mechanics::Spring::GetCurrentLength ( ) const

inline

Returns: Current distance between the two particles

Definition at line 116 of file Spring.hpp.

◆ GetDamping()

const Quantity< KilogramPerSecond > & Phyth::Mechanics::Spring::GetDamping ( ) const

inline

Returns: Damping coefficient c (kg/s)

Definition at line 113 of file Spring.hpp.

◆ GetElasticEnergy()

Quantity< Joule > Phyth::Mechanics::Spring::GetElasticEnergy ( ) const

inline

Compute the elastic potential energy stored in the spring.

Returns: 1/2 * k * elongation^2 (Joules)

Definition at line 161 of file Spring.hpp.

◆ GetElongation()

Quantity< Meter > Phyth::Mechanics::Spring::GetElongation ( ) const

inline

Returns: Current elongation (current_length - rest_length)

Definition at line 121 of file Spring.hpp.

◆ GetEnergyDensity()

Quantity< Newton > Phyth::Mechanics::Spring::GetEnergyDensity ( ) const

inline

Compute energy per unit length.

Returns: ElasticEnergy / CurrentLength (Newtons)

Note: If current_length is zero, this will produce a division by zero. Caller should ensure the particles are separated.

Definition at line 174 of file Spring.hpp.

◆ GetParticle1()

const std::shared_ptr< Particle > & Phyth::Mechanics::Spring::GetParticle1 ( ) const

inline

Returns: Shared pointer to the first particle

Definition at line 101 of file Spring.hpp.

◆ GetParticle2()

const std::shared_ptr< Particle > & Phyth::Mechanics::Spring::GetParticle2 ( ) const

inline

Returns: Shared pointer to the second particle

Definition at line 104 of file Spring.hpp.

◆ GetRestLength()

const Quantity< Meter > & Phyth::Mechanics::Spring::GetRestLength ( ) const

inline

Returns: Current rest length (constant unless modified)

Definition at line 107 of file Spring.hpp.

◆ GetStiffness()

const Quantity< NewtonPerMeter > & Phyth::Mechanics::Spring::GetStiffness ( ) const

inline

Returns: Spring stiffness constant k (N/m)

Definition at line 110 of file Spring.hpp.

◆ SetDamping()

void Phyth::Mechanics::Spring::SetDamping ( const Quantity< KilogramPerSecond > & damping )

inline

Set a new damping coefficient.

Parameters

damping New damping coefficient (must be non-negative)

Exceptions

std::invalid_argument If damping < 0

Definition at line 151 of file Spring.hpp.

◆ SetRestLength()

void Phyth::Mechanics::Spring::SetRestLength ( const Quantity< Meter > & rest_length )

inline

Set a new rest length.

Parameters

rest_length New rest length (must be positive finite)

Exceptions

std::invalid_argument If rest_length <= 0

Definition at line 129 of file Spring.hpp.

◆ SetStiffness()

void Phyth::Mechanics::Spring::SetStiffness ( const Quantity< NewtonPerMeter > & stiffness )

inline

Set a new stiffness.

Parameters

stiffness New stiffness (must be non-negative)

Exceptions

std::invalid_argument If stiffness < 0

Definition at line 140 of file Spring.hpp.

◆ validateDamping()

static void Phyth::Mechanics::Spring::validateDamping ( const Quantity< KilogramPerSecond > & damping )

inlinestaticprivate

Definition at line 198 of file Spring.hpp.

◆ validateRestLength()

static void Phyth::Mechanics::Spring::validateRestLength ( const Quantity< Meter > & length )

inlinestaticprivate

Definition at line 186 of file Spring.hpp.

◆ validateStiffness()

static void Phyth::Mechanics::Spring::validateStiffness ( const Quantity< NewtonPerMeter > & stiffness )

inlinestaticprivate

Definition at line 192 of file Spring.hpp.

Member Data Documentation

◆ damping_

Quantity<KilogramPerSecond> Phyth::Mechanics::Spring::damping_

private

Definition at line 183 of file Spring.hpp.

◆ p1_

std::shared_ptr<Particle> Phyth::Mechanics::Spring::p1_

private

Definition at line 179 of file Spring.hpp.

◆ p2_

std::shared_ptr<Particle> Phyth::Mechanics::Spring::p2_

private

Definition at line 180 of file Spring.hpp.

◆ rest_length_

Quantity<Meter> Phyth::Mechanics::Spring::rest_length_

private

Definition at line 184 of file Spring.hpp.

◆ stiffness_

Quantity<NewtonPerMeter> Phyth::Mechanics::Spring::stiffness_

private

Definition at line 182 of file Spring.hpp.

The documentation for this class was generated from the following file:

include/Phyth/Elements/Mechanics/Spring.hpp

Public Member Functions

Static Private Member Functions

Private Attributes

Detailed Description

Constructor & Destructor Documentation

◆ Spring()

Member Function Documentation

◆ Constrain()

◆ GetCurrentLength()

◆ GetDamping()

◆ GetElasticEnergy()

◆ GetElongation()

◆ GetEnergyDensity()

◆ GetParticle1()

◆ GetParticle2()

◆ GetRestLength()

◆ GetStiffness()

◆ SetDamping()

◆ SetRestLength()

◆ SetStiffness()

◆ validateDamping()

◆ validateRestLength()

◆ validateStiffness()

Member Data Documentation

◆ damping_

◆ p1_

◆ p2_

◆ rest_length_

◆ stiffness_