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thực tập mô phỏng ckt

Thực tập MPCKT

ThS. Nguyễn Thái Hiền
Email: thnguyen@hcmut.edu.vn
Phone: 0909450208
Facebook: thaihienvl@yahoo.com

Department of Engineering Mechanics, Room 106 B4, University of Technology
Tel: 08.38660568 - Fax: 08.38660568 - Email: bmcokythuat@hcmut.edu.vn - Website: www.fas.hcmut.edu.vn


Thực tập MPCKT

5.1. Introduction
5.2. Shell modeling
5.3. Exercises

Department of Engineering Mechanics, Room 106 B4, University of Technology
Tel: 08.38660568 - Fax: 08.38660568 - Email: bmcokythuat@hcmut.edu.vn - Website: www.fas.hcmut.edu.vn



Thực tập MPCKT
Thin Plate Theory ( Kirchhoff Plate Theory)
Assumptions (similar to those in the beam theory):
A straight line along the normal to the mid surface remains straight
and normal to the deflected mid surface after loading, that is, these
is no transverse shear deformation:

 xz   yz  0
Thick Plate Theory (Mindlin Plate Theory)
If the thickness t of a plate is not “thin”, t/L = 1/10 (L = a
characteristic dimension of the plate), then the thick plate theory by
Mindlin should be applied. This theory accounts for the angle
changes within a cross section, that is,

 xz  0,  yz  0
Department of Engineering Mechanics, Room 106 B4, University of Technology
Tel: 08.38660568 - Fax: 08.38660568 - Email: bmcokythuat@hcmut.edu.vn - Website: www.fas.hcmut.edu.vn


Thực tập MPCKT
Shells and Shell Elements
Shells – Thin structures witch span over curved surfaces.

Example:

Containers, pipes, tanks;
Car bodies;
Sea shell, egg shell (the wonder of the nature);

Department of Engineering Mechanics, Room 106 B4, University of Technology
Tel: 08.38660568 - Fax: 08.38660568 - Email: bmcokythuat@hcmut.edu.vn - Website: www.fas.hcmut.edu.vn


Thực tập MPCKT
Shell elements in ANSYS
Name

Element Description

Notes



SHELL181

4-Node Structural Shell

6 dof at each node

SHELL281

8-Node Structural Shell

6 dof at each node

SHELL163

Explicit Thin Structural Shell

12 dof at each node

SHELL209

3-Node Axisymmetric Shell

SHELL208

2-Node Axisymmetric Shell

SHELL131

4-Node Thermal Shell

SHELL132

8-Node Thermal Shell





Department of Engineering Mechanics, Room 106 B4, University of Technology
Tel: 08.38660568 - Fax: 08.38660568 - Email: bmcokythuat@hcmut.edu.vn - Website: www.fas.hcmut.edu.vn


Thực tập MPCKT
SHELL181
- Element Description:
SHELL181 is suitable for analyzing thin to moderately-thick shell
structures. It is a four-node element with six degrees of freedom at
each node: translations in the x, y, and z directions, and rotations
about the x, y, and z-axes. (If the membrane option is used, the
element has translational degrees of freedom only). The degenerate
triangular option should only be used as filler elements in mesh
generation.
SHELL181 is well-suited for linear, large rotation, and/or large strain
nonlinear applications. Change in shell thickness is accounted for in
nonlinear analyses.
SHELL181 may be used for layered applications for modeling
composite shells or sandwich construction.

Department of Engineering Mechanics, Room 106 B4, University of Technology
Tel: 08.38660568 - Fax: 08.38660568 - Email: bmcokythuat@hcmut.edu.vn - Website: www.fas.hcmut.edu.vn


Thực tập MPCKT
SHELL181
SHELL181 Input Data
- SHELL181 Geometry

Department of Engineering Mechanics, Room 106 B4, University of Technology
Tel: 08.38660568 - Fax: 08.38660568 - Email: bmcokythuat@hcmut.edu.vn - Website: www.fas.hcmut.edu.vn


Thực tập MPCKT
SHELL181
SHELL181 Input Data
- Single-Layer Definition
To define the thickness (and other information), use section
definition, as follows:
SECTYPE,,SHELL
SECDATA,THICKNESS, ...

- Multilayer Definition
The shell section commands allow for layered shell definition.
Options are available for specifying the thickness, material,
orientation, and number of integration points through the
thickness of the layers.

Department of Engineering Mechanics, Room 106 B4, University of Technology
Tel: 08.38660568 - Fax: 08.38660568 - Email: bmcokythuat@hcmut.edu.vn - Website: www.fas.hcmut.edu.vn


Thực tập MPCKT
Ex1:Curved shell with a rectangular hole
R=600
Fx
800
Fz

Using the input data listed below
the stress distribution should be
calculated for a shell with a
rectangular hole.
Given:

500
300

500

1200

E = 210000 MPa
 = 0,3
FX = 10 kN
FZ = 1 kN

t = 10

Department of Engineering Mechanics, Room 106 B4, University of Technology
Tel: 08.38660568 - Fax: 08.38660568 - Email: bmcokythuat@hcmut.edu.vn - Website: www.fas.hcmut.edu.vn


Thực tập MPCKT
Ex1:Curved shell with a rectangular hole
/PREP7
ET,1,181
SECTYPE,SHELL
SECDATA,10
MP,EX, 1, 210000
MP,NUXY,
CSYS,5 1, 0.3
K,1,600,0,0
K,2,600,40,0
K,3,600,40,1200
K,4,600,0,1200
K,5,600,0,500
K,6,600,25,500
K,7,600,25,800
K,8,600,0,800
A,1,2,3,4
A,5,6,7,8
ASBA,1,2 ASBA,1,2
Department of Engineering Mechanics, Room 106 B4, University of Technology
Tel: 08.38660568 - Fax: 08.38660568 - Email: bmcokythuat@hcmut.edu.vn - Website: www.fas.hcmut.edu.vn


Thực tập MPCKT
Ex1:Curved shell with a rectangular hole
ESIZE,50
AMESH,ALL
CSYS,0
ARSYM,Z,3,,,,
NUMM,NODE

! reflection. Include nodes and elements
! Merges coincident nodes

Department of Engineering Mechanics, Room 106 B4, University of Technology
Tel: 08.38660568 - Fax: 08.38660568 - Email: bmcokythuat@hcmut.edu.vn - Website: www.fas.hcmut.edu.vn


Thực tập MPCKT
Ex1:Curved shell with a rectangular hole
FINISH
/ SOLU
ANTYPE, STAT, NEW
NSEL, S, LOC, Y, 0
D, ALL, ALL
ALLSEL
F, 11, FX, 10000
F, 11, FZ, 1000
NSUB, 1
OUTRE, ALL, ALL
SOLVE
FINISH

Department of Engineering Mechanics, Room 106 B4, University of Technology
Tel: 08.38660568 - Fax: 08.38660568 - Email: bmcokythuat@hcmut.edu.vn - Website: www.fas.hcmut.edu.vn


Thực tập MPCKT
All edges are clamped. A constant pressure of 0.05 N/mm2acts on the
underside of the shell (i.e. the pressure acts in the +z direction). Since
the geometry and loads are symmetric about both the x and y-axes, we
need to model only one-quarter of the structure. The dimensions of the
plate and stiffeners are shown in the figure below which shows only onequarter of the structure. The Young's modulus E =7.3x104 MPa and

the Poisson ratio is 0.33.

Department of Engineering Mechanics, Room 106 B4, University of Technology
Tel: 08.38660568 - Fax: 08.38660568 - Email: bmcokythuat@hcmut.edu.vn - Website: www.fas.hcmut.edu.vn



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