Добавил:
Опубликованный материал нарушает ваши авторские права? Сообщите нам.
Вуз: Предмет: Файл:
ANSYS.pdf
Скачиваний:
875
Добавлен:
31.08.2019
Размер:
31.29 Mб
Скачать

vk.com/club152685050State-Space Matrices Export| vk.com/id446425943

The initial condition is calculated from the first load vector.

Velocity and acceleration results are not included.

The SML format for Simplorer is used to printout the state-space matrices.

If your model can be described by this first set of criteria, issue the following to export the statespace matrices:

! ** inputs definition

 

 

*dim,inputTab,,2,2

 

 

*dim,inputLab,CHAR,2

 

 

inputTab(1,1)

= 413

! node 413

inputTab(1,2)

= 1

! ux

 

inputLab(1) =

‘n413_ux’

 

 

inputTab(2,1)

= node(50e-2,0,45e-2)

! node @(.5,0,.45)

inputTab(2,2)

= 4

 

! rotx

inputLab(2) =

‘n01_rotx’

 

 

! ** outputs definition

 

 

*dim,outputTab,,1,2

 

 

*dim,outputLab,CHAR,1

 

 

outputTab(1,1) = 1022

! node 1022

outputTab(1,2) = 1

! ux

 

outputLab(1) = ‘n1022_ux’

 

 

spmwrite,modal,10,inputTab,inputLab,outputTab,outputLab,1

2.The second set of model criteria are as follows:

All modes are taken into account.

The inputs are based on all existing load vectors from the modal analysis.

The outputs are equal to the inputs.

There is no initial condition.

Velocity and acceleration results are not included.

The dense format is used to printout the state-space matrices.

If your model can be described by this second set of criteria, issue the following to export the statespace matrices:

spmwrite,modal, ,, ,, ,, ,0

15.1.2. Example of Reduced Model Generation in ANSYS and Usage in Simplorer

15.1.2.1. Problem Description

The model in this example is a basic representation of a disk drive suspension as described in Hatch[1]. It is a clamped-free beam with a mass and spring at tip. The mass represents the recording head. The reduced model is generated in ANSYS and imported into Simplorer where global half-sine acceleration is applied in a transient analysis.

 

Release 15.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information

342

of ANSYS, Inc. and its subsidiaries and affiliates.

vk.com/club152685050 | vk.com/id446425943

State-Space Matrices Based on Modal Analysis

15.1.2.2. Problem Specifications

Material

Young Modulus: 190e+6 mN/mm2

Density: 7.83e-6 kg/mm3

Poisson ratio: 0.293

Beam

Length: 20 mm

Area: 0.15 mm2

Cross section inertia IYY: 0.05 mm4

Cross Section inertia IZZ: 0.00007031 mm4

Spring

Stiffness: 1.e+7 N/mm

Mass at tip

Mass: 1.e-6 kg

15.1.2.3. Input File for the Analysis

Use the input below to generate the state-space matrices file (file.spm) based on the first 3 modes plus the residual vector.

/title, Beam on Shaker (ACEL) - SPMWRITE 3 modes + resvec /prep7

!** Parameters num_elem = 16 nummodes = 2*num_elem

!** Material ex,1,190e6 dens,1,7.83e-6 nuxy,1,0.293

!** Properties r,1,0.15,0.05,0.00007031,0.075,0.2 r,2,1000000 r,3,0.00002349,0.00002349,0.00002349

!Nodes

n,1,0,0,0 n,num_elem+1,20,0,0 fill,1,num_elem+1 n,num_elem+2,20,0,-3 nall

!** Beam et,1,4 type,1 mat,1 real,1 e,1,2

egen,num_elem,1,-1

!** Spring

Release 15.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information

 

of ANSYS, Inc. and its subsidiaries and affiliates.

343

vk.com/club152685050State-Space Matrices Export| vk.com/id446425943

et,2,14

type,2

real,2 e,num_elem+1,num_elem+2

!** Mass et,3,21 type,3 real,3 e,num_elem+1

!** Constraints d,1,all,0 d,num_elem+2,all,0 nsel,s,node,,2,num_elem+1 d,all,ux

d,all,uy

d,all,rotx

d,all,rotz

nsel,all fini

!** Modal analysis /solu

antype,modal

modopt,lanb,3

! << 3 modes

mxpand,3

 

resvec,on

! << residual vector

acel,,,1.0

! << load vector definition

dmprat,0.02

! << modal damping

solve

 

fini

 

/post1

/eshape,1

! ** Definition of the output *dim,output,,1,2

output(1,1) = num_elem+1 ! << node at tip

output(1,2) = 3

!

<< UZ

*dim,outputLab,CHAR,1

 

outputLab(1) = 'UZtip'

! ** Write SPM file: input = load vector spmwrite, modal, ,,, output, outputLab *list,,spm

fini

The state-space matrices file can be imported in Simplorer using: Simplorer Circuit > SubCircuit >

Add Mechanical Component

A transient analysis is performed in Simplorer for the 3 following reduced models:

All 32 modes are used.

First 3 modes are used.

First 3 modes plus residual vector are used (ANSYS input is listed above). The schematic of the simulation is shown on the figure below:

 

Release 15.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information

344

of ANSYS, Inc. and its subsidiaries and affiliates.

vk.com/club152685050 | vk.com/id446425943

State-Space Matrices Based on Modal Analysis

Figure 15.1: Simulation Schematic

A zoom on the graph showing the evolution of the spring force is given below:

Figure 15.2: Evolution of Spring Force

The reduced model based on the first 3 modes (red curve) is not accurate. When the residual vector is included (purple curve), the spring force is similar to the reference given by the 32 modes reduced model (dotted curve).

Release 15.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information

 

of ANSYS, Inc. and its subsidiaries and affiliates.

345

vk.com/club152685050 | vk.com/id446425943

 

Release 15.0 - © SAS IP, Inc. All rights reserved. - Contains proprietary and confidential information

346

of ANSYS, Inc. and its subsidiaries and affiliates.