R101 Airship Disaster and the Broken Elevator Cable

Author(s):  
B. Lawton
Keyword(s):  
Author(s):  
H. Ren ◽  
W. D. Zhu

A spatial discretization and substructure method is developed to calculate the dynamic responses of one-dimensional systems, which consist of length-variant distributed-parameter components such as strings, rods, and beams, and lumped-parameter components such as point masses and rigid bodies. The dependent variable, such as the displacement, of a distributed-parameter component is decomposed into boundary-induced terms and internal terms. The boundary-induced terms are interpolated from the boundary motions, and the internal terms are approximated by an expansion of trial functions that satisfy the corresponding homogeneous boundary conditions. All the matching conditions at the interfaces of the components are satisfied, and the expansions of the dependent variables of the distributed-parameter components absolutely and uniformly converge. The spatial derivatives of the dependent variables, which are related to the internal forces/moments, such as the axial forces, bending moments, and shear forces, can be accurately calculated. Assembling the component equations and the geometric matching conditions that arise from the continuity relations leads to a system of differential algebraic equations (DAEs). When some matching conditions are linear algebraic equations, some generalized coordinates can be represented by others so that the number of the generalized coordinates can be reduced. The methodology is applied to moving elevator cable-car systems in Part II of this work.


2013 ◽  
Vol 711 ◽  
pp. 327-332
Author(s):  
Yi Su ◽  
Zhen Zhang ◽  
Tao Zhang ◽  
Ming Li Yang ◽  
Mei Lin ◽  
...  

The detection mechanism of Magnetic Flux Leakage (MFL) Method of elevator cable is proposed. Using Gauss-Mercury method to analyze the influence of different factors that lift-off value, fracture width, broken wires number and diameter and depth all that based on the collecting experimental system of MFL signals. The method can be used to optimize the detection probe design and detection signal processing.


2018 ◽  
Vol 145 ◽  
pp. 165-173 ◽  
Author(s):  
Yoji Ishikawa ◽  
Kiyotoshi Otsuka ◽  
Yoshiki Yamagiwa ◽  
Hinata Doi

2005 ◽  
Vol 128 (1) ◽  
pp. 66-78 ◽  
Author(s):  
W. D. Zhu ◽  
Y. Chen

The vibratory energy of a moving cable in an elevator increases in general during upward movement. A control method is presented to dissipate the energy associated with the lateral vibration of the cable. A novel experimental method is developed to validate the theoretical predictions for the uncontrolled and controlled lateral responses of a moving cable in a high-rise elevator. This includes the design and fabrication of a scaled elevator, experimental setup, and development of measurement and parameter estimation techniques. Experimental results show good agreement with the theoretical predictions.


2020 ◽  
Vol 55 (8) ◽  
pp. 1185-1193
Author(s):  
Yu. A. Sadov ◽  
A. B. Nuralieva

2015 ◽  
Vol 80 (3) ◽  
pp. 1613-1630 ◽  
Author(s):  
Sajad H. Sandilo ◽  
Wim T. van Horssen
Keyword(s):  

2013 ◽  
Vol 135 (5) ◽  
Author(s):  
H. Ren ◽  
W. D. Zhu

This paper uses the methodology developed in Part I of this work to study the longitudinal, transverse, and their coupled vibrations of moving elevator cable-car systems. A suspension cable is a one-dimensional length-variant distributed-parameter component. When there is only one suspension cable connected to the car, the car is modeled as a point mass. When there are multiple suspension cables, the car is modeled as a rigid body, and the rotation of the car is considered. There are complicated matching conditions between the cable and car, which cannot be satisfied in the classical assumed modes method but can be satisfied in the current method. Hence, not only the longitudinal and transverse displacements but also the internal forces/moment, such as the axial force, the bending moment, and the shear force, which are related to the spatial derivatives of the longitudinal and transverse displacements, are accurately calculated. The results from different choices of boundary motions and trial functions are essentially the same, and the convergence is much faster than that of the assumed modes method. The longitudinal-transverse coupled vibrations of a moving cable-car system are also studied using the current method, and the results are compared with those from the linear models. While the result from the linear model for the transverse vibration agrees well with that from the nonlinear coupled model, the axial force from the linear model can significantly differ from that from the nonlinear model when the car approaches the top of the hoistway.


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