Exact Dynamic Analysis of Shallow Sagged Cable System — Theory and Experimental Verification

2019 ◽  
Vol 19 (12) ◽  
pp. 1950153 ◽  
Author(s):  
Fei Han ◽  
Yingluo Zhang ◽  
Jubao Zang ◽  
Ning Zhen
Keyword(s):  
Dynamic Analysis ◽  
Performance Monitoring ◽  
Dynamic Stiffness ◽  
Analytical Form ◽  
Frequency Equation ◽  
Cable System ◽  
Engineering Structures ◽  
Analysis Theory ◽  
Modern Engineering ◽  
Iteration Methods

With the increase of the span and height of modern engineering structures, the design length of engineering cables is increasing while the structural form is becoming more complicated, whose dynamic problem has become the key to structural design, performance monitoring and maintenance and vibration control. Therefore, it is necessary to study and develop a unified dynamic analysis theory for complex cable system with high calculation accuracy and efficiency to meet the requirements of exact analysis of engineering structures. In view of this, a unified dynamic analysis method for shallow sagged cable system is proposed in this paper based on the dynamic stiffness method. Since the derivation process is given in analytical form, the calculation accuracy and efficiency are promoted greatly. Full-scale cable test and numerical cases are used to verify the accuracy of the proposed method. Results show that the proposed method is in good agreement with the measured results and can effectively overcome the “root-missing” phenomenon existing in conventional iteration methods when solving the transcendental frequency equation.

scholarly journals An Exact Dynamic Analysis Method for Shallow Sagged Cables

2020 ◽  
Vol 38 (2) ◽  
pp. 451-457
Author(s):  
Yi Cao ◽  
Fei Han ◽  
Kai Yang ◽  
Yingluo Zhang
Keyword(s):  
Dynamic Analysis ◽  
Performance Monitoring ◽  
Dynamic Stiffness ◽  
Analytical Form ◽  
Frequency Equation ◽  
Analysis Method ◽  
Cable System ◽  
Engineering Structures ◽  
Cable Structure ◽  
Modern Engineering

With the increase of the span and height of modern engineering structures, the design complexity of the cable structure is constantly increasing, whose dynamic problem has become the key to structural design, performance monitoring and maintenance, and vibration control. Therefore, it is necessary to study and develop a new dynamic analysis theory for complex cable system with higher calculation accuracy and efficiency to meet the requirements of exact analysis of engineering structures. In view of this, a novel dynamic analysis method for shallow sagged cable system is proposed in this paper based on the dynamic stiffness method. Since the derivation process is given in analytical form, the calculation accuracy and efficiency are promoted greatly. The numerical cases are used to verify the accuracy of the proposed dynamic analysis method, meanwhile, the simulation results show that the proposed method can overcome the "root missing" phenomenon when solving the frequency equation by the existing analytical method.

Comparison of Static and Dynamic Stiffness for Beams Undergoing Flexural and Torsional Loading With an Intermediate Mass

2000 ◽  
Author(s):  
Arnoldo Garcia ◽  
Arnold Lumsdaine ◽  
Ying X. Yao
Keyword(s):  
Closed Form ◽  
Natural Frequency ◽  
Cross Sections ◽  
Dynamic Stiffness ◽  
Closed Form Solution ◽  
Frequency Equation ◽  
Form Solution ◽  
Torsional Loading ◽  
Intermediate Mass ◽  
Form Equation

Abstract Many studies have been performed to analyze the natural frequency of beams undergoing both flexural and torsional loading. For example, Adam (1999) analyzed a beam with open cross-sections under forced vibration. Although the exact natural frequency equation is available in literature (Lumsdaine et al), to the authors’ knowledge, a beam with an intermediate mass and support has not been considered. The models are then compared with an approximate closed form solution for the natural frequency. The closed form equation is developed using energy methods. Results show that the closed form equation is within 2% percent when compared to the transcendental natural frequency equation.

scholarly journals On the assessment of existing civil engineering structures

2018 ◽  
Vol 174 ◽  
pp. 03003
Author(s):  
Tadeusz Chmielewski
Keyword(s):  
Social Issue ◽  
Structural Analysis ◽  
Performance Monitoring ◽  
Civil Engineering ◽  
Working Life ◽  
Financial Resources ◽  
Final Report ◽  
Engineering Structures ◽  
Detailed Assessment ◽  
Civil Engineering Structures

The paper deals with the reasons for technical and moral deterioration of civil engineering structures, which constitute the enormous economic and political assets in every country. Extending their working life is an important social issue with always limited financial resources. In the next part, the following is presented: provisions of the building law, the procedure of the preliminary and detailed assessment with a structural analysis and proposals for possible interventions (e.g. rehabilitation, performance monitoring). The paper ends with a proposal of how to prepare the final report which should be issued upon the completion of the assessment, and the example of the structure after rehabilitation.

scholarly journals Dynamic analysis of the turbo – generator foundation structure

2020 ◽  
Vol 310 ◽  
pp. 00035
Author(s):  
Jan Benčat ◽  
Michal Tomko ◽  
Michal Lukáč
Keyword(s):  
Numerical Analysis ◽  
Power Plant ◽  
Dynamic Analysis ◽  
Dynamic Stiffness ◽  
Plant Industry ◽  
Characteristic Analysis ◽  
Current Trends ◽  
Turbo Generator ◽  
Foundation Structure

This paper provides view of current trends in the field of testing and numerical analysis of dynamic loading structures. It describes what is the role of structure dynamic characteristic analysis in the management of the structures construction and maintenance in power plant industry. The main objective of this study is the dynamic analysis of power plant turbo– generator foundation structure (TGFS) of electrical industry operation. Main purpose of performed study in 2017 was to check dynamic stiffness TGFS after fifty years TG (100 MW) performance which then enabled to prepare relevant data for making design renovation and strengthening of the TGSF.

scholarly journals Intelligent parameter identification for bridge cables based on characteristic frequency equation of transverse dynamic stiffness

2018 ◽  
Vol 39 (3) ◽  
pp. 678-689
Author(s):  
Danhui Dan ◽  
Bin Xu ◽  
Ye Xia ◽  
Xingfei Yan ◽  
Pengfei Jia
Keyword(s):  
Parameter Identification ◽  
Dynamic Stiffness ◽  
Low Frequency ◽  
Extreme Case ◽  
Frequency Measurement ◽  
Frequency Equation ◽  
Arbitrary Length ◽  
Transverse Dynamic ◽  
Cable Force

Determining the cable force and other parameters of cables is important for condition assessment of cable-stayed structures. This study proposes a frequency characteristic equation of transverse dynamic stiffness for cables; this equation is suitable for measuring the vibrations to evaluate the primary factors that influence the accuracy of cable parameter identification. Further, a cable parameter identification method based on the particle swarm optimization algorithm is proposed. The method is suitable for a cable system of arbitrary length and with moderate sag especially when the measurement quality of the modal frequencies of cables is poor. Both numerical case studies and a cable vibration test proved that the proposed method can identify parameters with high accuracy for cables of any length and for cases requiring low-frequency measurement. Moreover, structural modal order information is not required. The extreme case is that only one order frequency can achieve highly accurate result in this way. The proposed method is suitable for parameter identification of short cables, hanger cables, and parallel strand cables, which are commonly applicable in engineering applications.

AN APPLICATION CONCEPT OF THE FIBRE-OPTICAL TECHNOLOGY IN GEODETIC MONITORING OF ENGINEERING OBJECTS

2017 ◽  
Vol 166 (46) ◽  
pp. 60-74
Author(s):  
Krzysztof Karsznia ◽  
Konrad Podawca
Keyword(s):  
Risk Management ◽  
Large Scale ◽  
State Of The Art ◽  
Monitoring Systems ◽  
Management Approach ◽  
Engineering Structures ◽  
Geoinformation Systems ◽  
Current State ◽  
Modern Engineering ◽  
Integrated Risk

Monitoring of structures and other different field objects undoubtedly belongs to the main issues of modern engineering. The use of technologies making it possible to implement structural monitoring makes it possible to build an integrated risk management approach combining instrumental solutions with geoinformation systems. In the studies of engineering structures, there is physical monitoring mainly used for examining the physical state of the object - so-called SHM ("Structural Health Monitoring"). However, very important role is also played by geodetic monitoring systems (GMS). The progress observed in the field of IT and automatics has opened new possibilities of using integrated systems on other, often large-scale objects. Based on the current state-of-the-art, the article presents the concept of integration approaches of physical and geodetic monitoring systems in order to develop useful guidelines for further construction of an expert risk management system.

Paper 22: Metal Surfaces in Contact under Normal Forces: Some Dynamic Stiffness and Damping Characteristics

1967 ◽  
Vol 182 (11) ◽  
pp. 92-100 ◽  
Author(s):  
C. Andrew ◽  
J. A. Cockburn ◽  
A. E. Waring
Keyword(s):  
Surface Finish ◽  
Dynamic Stiffness ◽  
Joint Interface ◽  
Force Frequency ◽  
Oil Viscosity ◽  
Engineering Structures ◽  
Oil Film ◽  
Good Surface ◽  
Joint Area ◽  
Surface Finishes

This paper describes an experimental investigation into the dynamic stiffness characteristics of flat joints subjected to an alternating force superimposed on a steady pre-load. The joints consist of the interfaces between mild-steel discs arranged in a column, in sets with surfaces either turned or lapped together. The influences of pre-load and of alternating force frequency were investigated for both dry and oiled joints, for different values of surface finish, apparent joint area and oil viscosity. The ranges of the conditions considered are compatible with those existing in typical machine tool structures. It was found that the dynamic stiffness of dry joints is independent of frequency and no energy dissipation is measurable. The stiffness is primarily a function of pre-load and surface finish, with apparent joint area becoming important only for very good surface finishes. If oil is introduced into the joint interface, a quadrature stiffness component arises and is accompanied by an increase in the ‘in-phase’ stiffness component. The magnitudes of the oil film stiffness components decrease sharply with an increase in the effective oil film thickness, which is governed primarily by the surface roughness. They increase with oil viscosity, the apparent joint area and the frequency of vibration, and represent a potentially valuable source of vibration damping in engineering structures.

UV-Activated Frequency Control of Beams and Plates Based on Isogeometric Analysis

2017 ◽  
Author(s):  
Yujie Guo ◽  
Hornsen Tzou
Keyword(s):  
Isogeometric Analysis ◽  
Uv Light ◽  
Frequency Control ◽  
Dynamic Stiffness ◽  
Frequency Variation ◽  
Frequency Change ◽  
Engineering Structures ◽  
Plate Structures ◽  
C1 Continuity ◽  
Euler Bernoulli Beam

A new LaSMP smart material exhibits shape memory behaviors and stiffness variation via UV light exposures. This dynamic stiffness provides a new noncontact actuation mechanism for engineering structures. Isogeometric analysis utilizes high order and high continuity NURBS as basis functions which naturally fulfills C1-continuity requirement of Euler-Bernoulli beam and Kirchhoff plate theories. The UV light-activated frequency control of LaSMP laminated beam and plate structures based on the isogeometric analysis is presented in this study. The accuracy and efficiency of the proposed isogeometric approach are demonstrated via several numerical examples in frequency control. The results show that, with LaSMPs, broadband frequency control of beam and plate structures can be realized. Furthermore, the length of LaSMP patches on beams is varied, which further broadens its frequency variation ranges. Studies suggest that 1) the newly developed IGA is an effective numerical tool and 2) the maximum frequency change ratio of beam and plate structures respectively reach 24.30% and 6.37%, which demonstrates the feasibility of LaSMPs induced vibration control of structures.

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