CosmosWorks算法验证文件 10 (Static, Plastic Analysis)

tigerdak

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# C8 R4 B  c$ C5 d" ]' ?Title      Plastic Compression of a Pipe Assembly
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Reference:	S. H. Crandall, N. C. Dahl, An Introduction to the Mechanics of Solids, McGraw-Hill Book Co., Inc., New York, NY, 1959, pg. 180, ex. 5.1.
Analysis Type(s):	Static, Plastic Analysis

: h8 e" @, R6 a! kTest Case

Two coaxial tubes, the inner one of 1020 CR steel and cross-sectional area As, and the outer one of 2024-T4 aluminum alloy and of area Aa, are compressed between heavy, flat end plates, as shown below. Determine the load-deflection curve of the assembly as it is compressed into the plastic region by an axial displacement. Assume that the end plates are so stiff that both tubes are shortened by exactly the same amount.

7 P2 V! f- A& Z8 f! }& M0 `Figure 7.1  Pipe Assembly Problem Sketch



1 g+ I" t5 t0 MFigure 7.2  Pipe Assembly Finite Element Models



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Material Properties Es = 26,875,000 psi σ(yp)s = 86,000 psi Ea = 11,000,000 psi σ(yp)a = 55,000 psi υ = 0.3

Geometric Properties L= 10 in As = 7 in2 Aa = 12 in2

Loading 1st Load Step: δ = 0.032 in 2nd Load Step: δ = 0.05 in 3rd Load Step: δ = 0.10 in

Analysis Assumptions and Modeling NotesThe following tube dimensions, which provide the desired cross-sectional areas, are arbitrarily chosen. Inner (steel) tube: inside radius = 1.9781692 in., wall thickness = 0.5 in. Outer (aluminum) tube: inside radius = 3.5697185 in., wall thickness = 0.5 in.

The problem can be solved in one of three ways:

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• using PIPE20 - the plastic straight pipe element
• using SOLID45 - the 3-D structural solid element
• using SHELL43 - the 2-D plastic large strain shell element

3 T+ Z' [/ P3 n- c) u' F, I9 OIn the SOLID45 and SHELL43 cases, since the problem is axisymmetric, only a one element  Θ-sector is modeled. A small angle Θ = 6° is arbitrarily chosen to reasonably approximate the circular boundary with straight sided elements. The nodes at the boundaries have the UX (radial) degree of freedom coupled. In the SHELL43 model, the nodes at the boundaries additionally have the ROTY degree of freedom coupled.
( |) d; ?* i1 R6 MAn ANSYS warning message is issued stating that element 1, (PIPE20 pipe element) has a radius to thickness ratio less than 5. Because the model involves only axial loading, this does not affect the accuracy of the results.

' x1 o( Y3 l! o# Z: B# eResults Comparison
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		Target	ANSYS[1]	Ratio
PIPE20	Load, lb for Deflection = 0.032 in	1,024,400	1,024,400	1.000
	Load, lb for Deflection = 0.05 in	1,262,000	1,262,000	1.000
	Load, lb for Deflection = 0.1 in	1,262,000	1,262,000	1.000
SOLID45	Load, lb for Deflection = 0.032 in	1,024,400	1,022,529	0.998
	Load, lb for Deflection = 0.05 in	1,262,000	1,259,695	0.998
	Load, lb for Deflection = 0.1 in	1,262,000	1,259,695	0.998

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• From POST1 FSUM of bottom nodal forces (ΣFZ).

		Target	ANSYS[1]	Ratio
SHELL43	Load, lb for Deflection = 0.032 in	1,024,400	1,023,932	1.000
	Load, lb for Deflection = 0.05 in	1,262,000	1,261,423	1.000
	Load, lb for Deflection = 0.1 in	1,262,000	1,261,423	1.000

• From POST1 FSUM of bottom nodal forces (ΣFZ) X 360°/6°(Identified as parameter "LOAD").

me_five

看来楼主是有限元的高手，能不能给我这个初学者介绍几本书好入门，谢谢！！！

tigerdak

Cosmos帮助文件很好，ANSYS清华有一体资料我觉得比较好，字体清楚，写得也有条理，错误少，在ANSYS可以下到，PDF格式，因为没有封面，我不知道名字是什么。

告诉自己

楼上可以告诉你那本清华书的下载连接地址么？谢谢