scholarly journals A Dynamic Method to Predict the Earthquake-Triggered Sliding Displacement of Slopes

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Wenkai Feng ◽  
Zhichun Lu ◽  
Xiaoyu Yi ◽  
Shan Dong
Keyword(s):  
System Analysis ◽  
Critical Conditions ◽  
Newmark Method ◽  
Rigid Block ◽  
Block Model ◽  
Permanent Displacement ◽  
Rigid Plastic ◽  
Coupled Method ◽  
Flexible System ◽  
Decoupled Method

The earthquake-induced permanent displacement is an important index of the potential damage to a slope during an earthquake. The Newmark method assumes that a slope is a rigid-plastic body, and the seismic responses of sliding masses or seismic forces along the slide plane are ignored. The decoupled method considers no relative displacement across the sliding plane, so it overpredicts the seismic response of the sliding mass. Both dynamic and sliding analyses are performed in the coupled method, but when Ts/Tm is large, the results are unconservative. In this paper, a method is proposed to predict the earthquake-triggered sliding displacement of slopes. The proposed method is based on the Newmark rigid method, coupled method, and decoupled method considering both the forces at the sliding interface and the system dynamics under critical conditions. For the flexible system, the displacements are calculated with different stiffness values, and the results show that as the stiffness increases and tends to infinity, the critical acceleration and displacements of the proposed method are close to those of the Newmark method. The proposed method is also compared with the Newmark method with the period ratio Ts/Tm. At small values of Ts/Tm, the flexible system analysis results of the displacement are more conservative than those of the rigid block model; at larger values of Ts/Tm, the rigid block model is more conservative than the flexible system.

Simultaneous Shape and Topology Optimization of Planar Linkage Mechanisms Based on the Spring-Connected Rigid Block Model

2019 ◽  
Vol 142 (1) ◽  
Author(s):  
Jeonghan Yu ◽  
Sang Min Han ◽  
Yoon Young Kim
Keyword(s):  
Topology Optimization ◽  
Simultaneous Optimization ◽  
Optimization Process ◽  
Rigid Block ◽  
Low Resolution ◽  
Block Model ◽  
Shape And Topology Optimization ◽  
Fixed Grid ◽  
Computation Efficiency ◽  
And Topology

Abstract Using the topology optimization can be an effective means of synthesizing planar rigid-body linkage mechanisms to generate desired motion, as it does not require a baseline mechanism for a specific topology. While most earlier studies were mainly concerned with the formulation and implementation of topology optimization-based synthesis in a fixed grid, this study aims to realize the simultaneous shape and topology optimization of planar linkage mechanisms using a low-resolution spring-connected rigid block model. Here, we demonstrate the effectiveness of simultaneous optimization over a higher-resolution fixed-grid rigid block-based topology optimization process. When shape optimization to change the block shapes is combined with topology optimization to synthesize the mechanism, the use of low-resolution discretized models improves the computation efficiency considerably and helps to yield compact mechanisms with less complexity, making them more amenable to fabrication. After verifying the effectiveness of the simultaneous shape and topology optimization process with several benchmark problems, we apply the method to synthesize a mechanism which guides a planar version of a human's gait trajectory.

Automatic Synthesis of a Planar Linkage With a Stiffness-Varying Spring Connected Rigid Block Model

2007 ◽  
Author(s):  
Sang Jun Nam ◽  
Gang-Won Jang ◽  
Jung Hun Park ◽  
Jin Sub Hun ◽  
Yong Sub Yi ◽  
...  
Keyword(s):  
Minimization Problem ◽  
Variable Stiffness ◽  
Synthesis Process ◽  
Rigid Block ◽  
Linkage Mechanism ◽  
Block Model ◽  
Revolute Joints ◽  
Gradient Based ◽  
Input Motion ◽  
Linkage Model

A linkage mechanism is a device to convert an input motion into a desired motion in a machine or a robot. The traditional linkage synthesis practice is depended on the experience and intuition of the skilled designer. This practice based on trial and error approach or only size/shape changes of already-available mechanism often results in improper design. This observation has motivated us to develop a so-called “automatic” design methodology that determines the linkage type and dimensions during synthesis process. The synthesis process can be formulated as a minimization problem. However, the process can be extremely difficult and time-consuming unless there is a single unified linkage model that represents any linkage mechanism without complicating kinematic analysis and allows the use of an efficient gradient-based optimizer. The main contribution of this research is to propose a unified planar linkage model consisting of rigid blocks connected by zero-length springs having real-valued variable stiffness. Stiffness controlling variables are the design variable of the minimization problem and a general planar linkage can be simulated by the spring-connected rigid block model if the stiffness value is chosen appropriately. This work shows how new idea works and verifies this new approach on the synthesis of the planar linkages consisting of links and revolute joints.

scholarly journals Initiation, movement, and run-out of the giant Tsaoling landslide — What can we learn from a simple rigid block model and a velocity–displacement dependent friction law?

2014 ◽  
Vol 182 ◽  
pp. 158-181 ◽  
Author(s):  
Che-Ming Yang ◽  
Wei-Lun Yu ◽  
Jia-Jyun Dong ◽  
Chih-Yu Kuo ◽  
Toshihiko Shimamoto ◽  
...  
Keyword(s):  
Rigid Block ◽  
Block Model ◽  
Friction Law

scholarly journals Elastic Block Model in the North Andean Sliver

2021 ◽  
Author(s):  
Paul Jarrin ◽  
Jean-Mathieu Nocquet ◽  
Frederique Rolandone ◽  
Hector Mora-Paez ◽  
Patricia Mothes
Keyword(s):  
A Priori ◽  
Gps Data ◽  
Rigid Block ◽  
A Priori Information ◽  
Block Model ◽  
Complex Deformation ◽  
Slip Rates ◽  
The North ◽  
Interseismic Coupling ◽  
Priori Information

<p>The North Andean Sliver (hereinafter NAS) lies at the northwestern end of the South American plate (hereinafter SOAM). This extensive area exhibits a complex deformation process controlled by the interactions of Nazca, Caribbean, South America plates, and Panama block, producing crustal seismicity, arc-continental collision, and subduction processes. Previous models based on partial GPS data sets have estimated the NAS kinematics as a single rigid block moving towards northeast  at 8-10 mm/yr (Nocquet et al. 2014, Mora-Paez et al 2019). By contrary, geologic interpretations as well as seismotectonic data propose more complex kinematic models based on the interaction of several blocks (Audemard et al 2014, Alvarado et al 2016).  Here, we present an updated and most extensive interseismic horizontal velocity field derived from continuous and episodic GPS data between 1994 and 2019 that encompasses the whole North Andean Sliver.  We then interpret it, developing a kinematic elastic block model in order to simultaneously estimate rigid block rotations, consistent slip rates at faults and the spatial distribution of interseismic coupling at the Nazca/NAS megathrust interface. Our model is not constrained either by a priori information derived from geologic slip rates or by a priori information of creeping faults. In contrast with previous simplest models, our model will allow us to estimate the degree of slip partitioning more precisely along the NAZCA/SOAM convergence as well as an improved model of interseismic coupling. We will discuss our coupling distribution with respect to previous models, and our block geometry quantifying the goodness of fit, resolution,  and considering its consistency with geological interpretations.</p>

scholarly journals Nursing and rehabilitation of very preterm infants: current state of the problem

2017 ◽  
Vol 8 (2) ◽  
pp. 81-88
Author(s):  
Svetlana A Khmilevskaya ◽  
Nikolay I Zryachkin ◽  
Ekaterina S Shcherbatyuk ◽  
Elena I Ermolaeva ◽  
Anastasiya A Rebrova
Keyword(s):  
System Analysis ◽  
Inflammatory Diseases ◽  
Disease Incidence ◽  
Intrauterine Infection ◽  
Adverse Outcomes ◽  
Extremely Low Birth Weight ◽  
Critical Conditions ◽  
Very Preterm Infants ◽  
Very Preterm ◽  
Current State

The article deals with basic ethiopathogenetic factors of birth of extremely premature infants, their malconditions, disease incidence. The authors give live birth criteria adopted in Russia in 2011 according to WHO recommendations. The article presents basic ethiologic factors of prematurely born and the role of intrauterine infection (IUI) in the pathogenesis of this condition, also survival rate, mortality and adverse outcomes. These literatures devoted to the international experience of nursing of such children and forecasting of viability of newborns in the viability limit zone (VLZ) are provided. Reflects the basic malconditions typical of children with very low (VLBW) and extremely low birth weight (ELBW) and leading to disability (damage to the nervous, respiratory system, analysis unit, etc). It is shown significance of IUI in the formation of infectious and inflammatory diseases (IID), the place and especially the innate immune system in the implementation of anti-infectious protection and ways of its correction in severe forms of EWI. Need of development of the differentiated programs of the treatment-and-prophylactic actions directed to correction of critical conditions and simplification of a course of the developed diseases is proved.

The Spring-Connected Rigid Block Model Based Automatic Synthesis of Planar Linkage Mechanisms: Numerical Issues and Remedies

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Sang Jun Nam ◽  
Gang-Won Jang ◽  
Yoon Young Kim
Keyword(s):  
Closed Loop ◽  
Synthesis Method ◽  
Direct Application ◽  
Rigid Block ◽  
Block Model ◽  
Automatic Synthesis ◽  
Open Path ◽  
Synthesis Of Mechanisms ◽  
Input Motion ◽  
Linkage Synthesis

Because it is difficult to select in advance an appropriate linkage for converting an input motion to a desired output motion, a linkage synthesis method that does not require any baseline linkage would be preferred. To this end, an optimization-based linkage synthesis method that employs a spring-connected rigid block model has recently been suggested and applied for open-path problems. The objective of this study is to expand the method for the synthesis of more complex linkage mechanisms such as closed-loop linkages. Because the direct application of the method originally developed for open-path problems causes several numerical difficulties for closed-loop problems, an alternative optimization-based synthesis formulation is proposed in this investigation. The effectiveness of the suggested formulation is verified through several case studies including the synthesis of mechanisms generating closed paths.

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