ModalysObjects > Object Reference > Rectangular Plate - Fixed
page précédentepage suivante

Rectangular Plate - Fixed

Description

A rectangular plate fixed at its edges.

(make-object 'rect-plate ... )

Lisp Syntax and Default Values

A 'rect-plate can be created using the following Lisp syntax (the default values are shown for each of the physical parameters):

(make-object 'rect-plate

(modes 80)

(length0 .5)

(length1 .5)

(thickness .01)

(density 7800)

(poisson 0.3)

(young 2e11)

(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.
• thickness: in meters.
• density: in kg/m^3. See chart of material properties for appropriate values.
• young: Young's modulus, in N/m^2. See chart of material properties for appropriate values.
• poisson: Poisson Coeffieient. Usually has a value of 0.3. See general object information.
• 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 plate can be accessed in its z-direction ('normal) from any point on its surface.

(make-access my-plate my-2D-controller 'normal)

This makes an up-and-down access (in the z direction) at a point on the surface of my-plate. The point is defined by my-2D-controller where the first dimension is x and the second is y (the plate's corners being the points (0, 0), (0, 1), (1, 0) and (1, 1)). For example, in order to access the center of the plate we can say:

(make-access my-plate (const 0.5 0.5) 'normal)

Options

Tuning

A rect-plate can be tuned to a specific pitch, using the (set-pitch ...) function, by adjusting one of the following physical parameters:

• 'size
• 'thickness
• 'density
• 'young

Note that for 'size, both the x and y dimensions are scaled together proportionally in order to preserve the harmonic relationships the plate's mode frequencies.

(setq my-plate (make-object 'rect-plate))

(set-pitch my-plate 'size (const 440))

page précédentepage suivante