Rectangular Membrane - Fixed
Description
A rectangular membrane with a thickness of zero, fixed at the edges.
(make-object 'rect-membrane ... )
Syntax and Default Values
A 'rect-membrane can be created using the following Lisp syntax (the default values are shown for each of the physical parameters):
(make-object 'rect-membrane
(modes 80)
(length0 .5)
(length1 .5)
(tension 1000)
(surface-density .1)
(freq-loss 10)
(const-loss 10))
Parameters
The arguments for the physical parameters can be either numerical values or Modalys controllers (either dynamic or constant). If a given parameter is not supplied when using the Lisp syntax, the default parameter value will be used.
- modes: number of modes.
- length0: length along the x-axis in meters.
- length1: length along the y-axis in meters.
- tension: in Newtons.
- surface-density: surface density in kg. NB: was named "mass" in older versions of Modalys.
- freq-loss, const-loss: loss coefficients. See General object information.
Note that, unlike other objects, the values for freq-loss and const-loss default to 10 for this object.
Accesses
A rectangular membrane can be accessed in its z-direction ('normal) from any point on its surface.
(make-access my-membrane my-2D-controller 'normal)
(make-access my-membrane (const 0.5 0.5) 'normal)
Options
Tuning
A rect-membrane can be tuned to a specific pitch, using the (set-pitch ...) function, by adjusting one of the following physical parameters:
- 'size
- 'tension
- 'mass
Note that for 'size, both the x and y dimensions are scaled together proportionally in order to preserve the harmonic relationships the membrane's mode frequencies.
(setq my-membrane (make-object 'rect-membrane))
(set-pitch my-membrane 'size (const 110))
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