Shock Absorber
Spring and damper system that absorbs translational shocks
Libraries:
Simscape /
Driveline /
Couplings & Drives
Description
The Shock Absorber block represents a spring-damper system that absorbs vibrations. An internal force acts between ports R and C. This force is the sum of spring stiffness, damping, Coulomb friction, and hard-stop contributions. All force contributions are optional.
The block is a composite of these blocks:
Block | Function | Library |
---|---|---|
Loaded-Contact Translational Friction | Coulomb friction | Simscape / Driveline / Brakes & Detents / Translational |
Translational Damper | Damping | Simscape / Foundation Library / Mechanical / Translational Elements |
Translational Spring | Spring | |
Translational Hard Stop | Hard stop |
Assumptions and Limitations
Setting Hard stop to
Compliant hard stop
or setting Coulomb friction force to a nonzero value enhances model fidelity, but reduces simulation speed. For more information, see Driveline Simulation Performance.
Ports
Conserving
C — Case
mechanical translational
Mechanical translational conserving port associated with one end of the shock absorber. Positive force acts from port R to port C.
R — Rod
mechanical translational
Mechanical translational conserving port associated with one end of the shock absorber. Positive force acts from port R to port C.
Parameters
Spring-Damper
Spring stiffness — Stiffness of spring
1e4
N/m
(default) | nonnegative scalar
Value of the spring stiffness constant, k.
Viscous friction coefficient — Viscous friction coefficient
1e2
N*s/m
(default) | nonnegative scalar
Value of the viscous damping constant, b.
Coulomb friction force — Coulomb friction force
0
N
(default) | nonnegative scalar
Value of the Coulomb friction force. Setting the value to
0
eliminates the Coulomb friction force
contribution, which enhances simulation speed and makes the model more
suitable for HIL testing.
Ratio of static to kinetic friction — Static-to-kinetic friction ratio
1.1
(default) | scalar greater than or equal to 1
Value of the ratio of static friction to kinetic friction, Fs/Fk.
Velocity tolerance — Slip velocity threshold
0.001
m/s
(default) | positive scalar
Value of the relative velocity below which ports R and C lock and translate together. When the relative velocity is greater than this value, the ports slide relative to one another.
Hard Stops
Hard stop — Hard stop option
No hard stops - Suitable for HIL
simulation
(default) | Compliant hard stops
Whether to model translational hard stops. Select from these options:
No hard stops — Suitable for HIL simulation
— Enhance simulation speed by excluding the hard-stop force contribution.Compliant hard stops
— Enhance model fidelity by including the hard-stop force contribution.
Upper bound — Gap between slider and upper bound
0.1
m
(default) | scalar
Upper hard-stop position, UB. Positive displacement beyond the upper bound activates the hard-stop contact force. The value must be greater than the Lower bound parameter.
Dependencies
To enable this parameter, set Hard Stop to
Compliant hard stops
.
Lower bound — Gap between slider and lower bound
-0.1
m
(default) | scalar
Lower hard-stop position, LB. Negative displacement beyond the lower bound activates the hard-stop contact force. The value must be smaller than the Upper bound parameter.
Dependencies
To enable this parameter, set Hard Stop to
Compliant hard stops
.
Contact stiffness — Contact stiffness constant
1e6
N/m
(default) | nonnegative scalar
Value of the hard-stop stiffness constant, kHS.
Dependencies
To enable this parameter, set Hard Stop to
Compliant hard stops
.
Contact damping — Contact damping constant
1e4
N*s/m
(default) | positive scalar
Value of the hard stop damping constant, bHS. This parameter specifies a dissipating property of colliding bodies. The greater the value of the parameter, the more energy the hard stop dissipates during an interaction.
Dependencies
To enable this parameter, set Hard Stop to
Compliant hard stops
.
Hard stop model — Hard stop transition behavior
Stiffness and damping applied smoothly
through transition region, damped rebound
(default) | ...
Stiffness and rebound options for the hard stop model. The block uses a composite implementation of the Translational Hard Stop block. You can choose from the following options:
Stiffness and damping applied smoothly through transition region, damped rebound
Full stiffness and damping applied at bounds, undamped rebound
Full stiffness and damping applied at bounds, damped rebound
Based on coefficient of restitution
Transition region — Hard-stop transition distance
0.1
mm
(default) | positive scalar
Region where the force ramps up from zero to the full value. At the end of the transition region, the block applies full stiffness and damping.
Dependencies
To enable this parameter, set Hard Stop to
Stiffness and damping applied smoothly through
transition region, damped rebound
.
Coefficient of restitution — Ratio of final-to-initial relative speed between slider and stop after collision
0.7
(default) | unitless value between 0 and 1
Ratio of the final to the initial relative speed between the slider and the stop after the slider bounces.
Dependencies
To enable this parameter, set Hard stop to
Compliant hard stops
and
Hard stop model to Based on
coefficient of restitution
.
Static contact speed threshold — Threshold relative speed between slider and stop before collision
0.001
m/s
(default) | nonnegative scalar
Threshold relative speed between the slider and the stop before
collision. When the slider hits the case with speed less than the value
of this parameter, they stay in contact. Otherwise, the slider bounces.
To avoid modeling static contact between the slider and the case, set
this parameter to 0
.
Dependencies
To enable this parameter, set Hard stop to
Compliant hard stops
and
Hard stop model to Based on
coefficient of restitution
.
Static contact release force threshold — Threshold torque needed to transition from contact mode to free mode
0.001
N
(default)
Minimum torque needed to release the slider from a static contact mode.
Dependencies
To enable this parameter, set Hard stop to
Compliant hard stops
and
Hard stop model to Based on
coefficient of restitution
.
Extended Capabilities
C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.
Version History
Introduced in R2013aR2023a: Composite Hard Stop Updates
Due to updates in the Translational Hard Stop block, the Hard stop
model parameter now features the Coefficient of
restitution
option.
MATLAB 명령
다음 MATLAB 명령에 해당하는 링크를 클릭했습니다.
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