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MODIFIED ELASTIC
COMPENSATION METHOD FOR LIMIT
ANALYSIS
OF COMPLEX STRUCTURES
CHEN Lijie LIU Yinghua YANG Pu XU Bingye
(Department of Engineering Mechanics,
Tsinghua University, Beijing 100084
)
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Abstract: The
elastic compensation method (ECM) for structural limit analysis is a
simple and effective method for simple structures. However,
relatively greater computational errors and divergence are often
caused for complex structures. Addressing on these problems, the
present paper employs the fixed point theorem in Banach space to
discuss the convergence problem of the ECM for lower bound limit
load calculations. It can be pointed out that a good limit load
solution can be achieved only when the iterative elastic modulus
sequences satisfy the condition of contraction mapping. Based on
this idea, a modified elastic compensation method (KtECM)
is proposed. The KtECM adopts an iterative method,
in which the iterative elastic modulus sequences of the main
load-carrying elements in a structure satisfy the condition of
contraction mapping. At the same time, an adjustable factor
λ
related
with the stress concentration factor (Kt) of
structures is used to define a rational nominal stress. Limit loads
of several complex structures are calculated by different methods.
It reaches the conclusion that the KtECM can
provide a good estimation of plastic limit loads for complex
structures and preserves the advantages of simplicity, high
efficiency and convenience for engineering applications. The
adjustable factor can
make a balance between computational precision and time.
Key words: Complex structures Limit analysis
Modified elastic compensation method
The fixed point theorem in Banach space
CLC No: TB125
国家自然科学基金资助项目(50605039). Received 20060801,
received in revised form
20070111
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