Optimal load redistribution on interdependent networks under a novel flow interaction model

2020 ◽  
Vol 34 (11) ◽  
pp. 2050104
Author(s):  
Mingyu Huang ◽  
Li Ding ◽  
Wei Ding ◽  
Tao Lin ◽  
Zhihong Guan

Complex systems are always composed of many subsystems that exhibit interdependent relationship with each others. It becomes increasingly important across many fields to understand the effect of interdependence among these subsystems. In this paper, we consider a novel flow interaction model on a system comprising two networks with initial line loads and capacities. Once a line in one network is subjected to overload failure, its load will be redistributed to the whole system. Based on this model, we study how load transfer due to redistribution affects the dynamic process of failure propagation and the failure outbreak threshold. Furthermore, we solve an optimal load transfer problem to find the minimum cumulative cost on the low failure level. Our results provide theoretical guidance for optimal load scheduling to suppress cascades in the interdependent networks.

1996 ◽  
Vol 24 (4) ◽  
pp. 321-338 ◽  
Author(s):  
J. Padovan

Abstract This paper investigates the cord-matrix load transfer problem in twisted cord-rubber composites. The central feature of the study is to ascertain the polarizing effects of twist-induced coupling of the axial loads and torque. Particular emphasis is given to the end problem, namely the transition between the axial-circumferential shear stress-dominated end region and the axial normal stress and torque-controlled far-from-end zone. This is achieved through the development of both a closed form analytic formulation and its corroboration by a detailed finite element simulation.


Author(s):  
Andrei Costache ◽  
Kristian Glejbøl ◽  
Ion Marius Sivebæk ◽  
Christian Berggreen

Flexible risers are used in the oil industry to transport liquids and gas from the seafloor to extraction and production equipment at the sea surface. Ongoing research aims at using composite materials instead of steel, in order to reduce weight and increase stiffness. Ensuring an optimal load transfer between the composite and metal components is very important. This paper presents an improved method for anchoring a flat fiber-reinforced tendon using a double grip system with self-locking grips. The novelty is the combination of new experimental results and finite element (FE) analysis to develop a superior dry friction grip. Experimental results are carried using a dedicated test setup, through which the test parameters can be accurately controlled. The efficiency of the grip system during pullout is superior to results obtained with flat grips. Numerical results offer an in-depth understanding of the influence between friction, geometrical parameters, and performance, making it possible to optimize the design. Results show that this grip system offers immediate technical applications, in a variety of conditions.


1984 ◽  
Vol 8 (4) ◽  
pp. 219-226 ◽  
Author(s):  
P. Karasudhi ◽  
R.K.N.D. Rajapakse ◽  
K.K. Liyanage

This paper is a reconsideration of elastostatic load transfer problem of a long cylindrical elastic bar partially embedded in an elastic half space. Each problem is considered as consisting of two interacting systems, an extended half space and a one-dimensional fictitious bar. A compatibility condition is imposed near the interface of the interacting systems. In order to incorporate the real phenomenon of stress singularities at the ends of the bar, without carrying our a complicated derivation of the stress singularity factor, the basic unknown force at both ends of the fictitious bar is set to zero. However, the effects of the stress singularity are found to be not significant, especially for long bars and when the main concern is only on the force-displacement relationship at the top end of the bar.


1973 ◽  
Vol 40 (4) ◽  
pp. 997-1003 ◽  
Author(s):  
F. Erdogan ◽  
G. D. Gupta

The following load transfer problems are considered in this paper: torque transfer between an elastic shaft and a finite elastic disk or sleeve of different materials, torque transfer between two identical shafts coupled through a finite sleeve, and torque transfer between two dissimilar shafts coupled through a finite sleeve. In all cases it is assumed that the contact between the sleeve and the shafts is one of perfect adhesion accomplished through bonding or shrink-fit. The problems are shown to reduce to singular integral equations with generalized Cauchy kernels. Some numerical examples are worked out and the stress-intensity factors and distribution of contact stresses are given.


Author(s):  
Nhan Phan-Thien ◽  
Sangtae Kim

The acoustic and mechanical properties of cemented granular materials such as sedimentary rocks are directly related to the load transfer problem between two granules (Stoll). The theoretical description of granular materials has been based on the Hertzian contact problem between two elastic spherical inclusion in an elastic matrix, or its modifications; a review of the contact problem can be found in Johnson. In essence, the deformation problem resulting from a relative displacement between two nearby spherical elastic inclusions is studied, and the load transfer between the two is used to construct a constitutive theory for the particulate solid. In particular, Dvorkin et al. studied the deformation of an elastic layer between two spherical elastic grains, using a two-dimensional plane strain analysis similar to those of Tu and Gazis and Phan-Thien and Karihalo. They concluded that the elastic properties of the cemented system can depend strongly on the length of the cement layer and the stiffness of the cement. The main problem with the method is the assumption that the contribution to the load transfer between the granules comes from the region near contact. The assumption is well justified in the case where the Poisson’s ratio of the cement layer is 0.5 (incompressible), in which case the problem is equivalent to the corresponding Stokes flow problem where exact and asymptotic solutions are available (see, for example, Kim and Karrila). The Stokes asymptotic solution shows that the leading term in the load transfer is of O(є-1), where є is the dimensionless thickness of the cement layer. In the case where the Poisson’s ratio of the elastic layer is less than 0.5, it is not clear that the load is still strongly singular in є, and therefore a local stress analysis in the region of near contact may not necessarily yield an accurate answer, unless є is extremely small. The load transfer problem is pedagogic in that it allows us to demonstrate an effective technique often used in Stokes flow known as the reflection method, which has its basis in Faxén relations (discussed in the previous chapter).


2005 ◽  
Vol 42 (5) ◽  
pp. 1485-1493 ◽  
Author(s):  
Su-Hyung Lee ◽  
Choong-Ki Chung

The interactions among closely located piles and a cap in a pile group are complex. The current design practice for vertically loaded pile groups roughly estimates their overall behavior and generally yields conservative estimations of the group capacity. For a proper pile group design, factors such as the interaction among piles, the interaction between cap and piles, and the influence of pile installation method all need to be considered. This paper presents the results of the model test, which can be used to better understand the interactions of vertically loaded pile groups in granular soil. Load tests were carried out on the following: an isolated single pile, single-loaded center piles in groups, a footing without any piling, free standing pile groups, and piled footings. The influences of pile driving and the interactions among bearing components on load–settlement and load transfer characteristics of piles and on the bearing behavior of a cap in a group are investigated separately by comparing their respective test results. The favorable interaction effects that increase pile capacities are identified.Key words: pile group, pile installation, interaction, model test, free standing, piled footing.


1994 ◽  
Vol 61 (4) ◽  
pp. 971-975 ◽  
Author(s):  
Ven-Gen Lee ◽  
Toshio Mura

Based on the equivalent inclusion method, the load transfer problem of a finite cylindrical fiber embedded in an elastic half-space of different elastic properties is presented. The equivalent condition of inhomogeneity and inclusion problems simulates the fiber to an inclusion with chosen eigenstrains, and the problem is formulated to a set of integral equations with the unknown strength of eigenstrains. A numerical procedure is developed using a discretizing scheme by which the set of integral equations is reduced to a system of algebraic equations.


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