Damage mechanism of giant orthogonal grid barrel vault under strong earthquake

2019 ◽  
Vol 11 (1) ◽  
pp. 121-134
Author(s):  
Lin Qi ◽  
Wenbo Zhang ◽  
Ronglai Sun ◽  
Fang Liu
Keyword(s):  
Strong Earthquake ◽  
Seismic Analysis ◽  
Numerical Models ◽  
Plastic Hinge ◽  
Damage Mechanism ◽  
Geometrical Model ◽  
Content Type ◽  
Transfer Path ◽  
Orthogonal Grid ◽  
Material Utilization

Purpose Giant orthogonal grid barrel vault is generated by deleting members in the inessential force transfer path of the two-layer lattice barrel vault. Consisting of members in the essential transfer path only, giant orthogonal grid barrel vault is a new type of structure with clear mechanical behavior and efficient material utilization. The paper aims to discuss this issue. Design/methodology/approach The geometrical configuration of this structure is analyzed, and the geometrical modeling method is proposed. When necessary parameters are determined, such as the structural span, length, vault rise, longitudinal and lateral giant grid number and section height to top chord length ratio of the lattice member, the structure geometrical model can be generated. Findings Numerical models of giant orthogonal grid barrel vaults with different rise–span ratios are built using the member model that can simulate the pre-buckling and post-buckling behavior. So the possible member buckle-straighten process and the plastic hinge form–disappear process of the structure under strong earthquake can be simulated. Originality/value Seismic analysis results indicate that when the structure damages under strong earthquake there are a large number of buckling members and few endpoint plastic hinges in the structure. Dynamic damage of giant orthogonal grid barrel vault under strong earthquake is caused by buckling members that weaken the structural bearing capacity.

Nonlinear Seismic Responses Analysis of Jinwan Square No.9 Building

2014 ◽  
Vol 919-921 ◽  
pp. 999-1002
Author(s):  
Lin Qi ◽  
Zhao Wei Huang ◽  
Xue Ying Hu
Keyword(s):  
Shear Strength ◽  
Strong Earthquake ◽  
Seismic Analysis ◽  
Plastic Hinge ◽  
Time History ◽  
Beam Element ◽  
Structure Design ◽  
Three Dimension ◽  
Fiber Wall ◽  
Set Up

Nonlinear time history seismic analysis of Jinwan square No. 9 building under strong earthquake is made. Three dimension structural nonlinear analysis and performance estimate programme Perform-3D is used to establish the calculatrion model. FEMA beam, shear strength section are used to set up the frame beam element modal; Moment plastic hinge, shear plastic hinge and elastic beam section are used to set up the link beam element modal; FEAM column and shear strength section are used to set up the column element modal; fiber wall element is used to model the sheae wall. Performances of the structure under strong earthquake are analysed. Numerical calculation results indicate that the structure design satisfies the preestablished performance targets.

scholarly journals Timber frame houses resistant to dynamic loads - seismic analysis

2018 ◽  
Vol 219 ◽  
pp. 01001
Author(s):  
Marcin Szczepański ◽  
Wojciech Migda
Keyword(s):  
Polyurethane Foam ◽  
Considerable Increase ◽  
Seismic Analysis ◽  
Numerical Models ◽  
Mineral Wool ◽  
Seismic Excitations ◽  
Timber Frame ◽  
Frame Building ◽  
Frame Buildings ◽  
Node Displacement

The aim of the article is to present results of seismic analysis results of two real-sized timber frame buildings subjected to seismic excitations. The first model was insulated with mineral wool, the second one with polyurethane foam. Technology and specifications involved in both models construction is based on the previously conducted experimental research on timber frame houses, including wall panels tests, wall numerical models and study on material properties and precisely reflect results of the those research. During the seismic analysis reference node located in buildings were selected. In selected node displacement values were measured and compared between two analyzed models. The results of the numerical analysis presented in the article indicate that the application of polyurethane foam for a skeleton filling of the timber-frame building leads to the increase in stiffness as well as damping of the whole structure, which results in a considerable increase in the seismic resistance of the structure.

scholarly journals History, observation and mathematical models in the seismic analysis of the Valadier abutment area in the Colosseum

1995 ◽  
Vol 38 (5-6) ◽  
Author(s):  
G. Croci ◽  
D. D'Ayala ◽  
R. Liburdi
Keyword(s):  
Mathematical Models ◽  
Seismic Analysis ◽  
Numerical Models ◽  
Time History ◽  
Historical Records ◽  
Direct Integration ◽  
Structural Behaviour ◽  
Seismic Behaviour ◽  
Before And After ◽  
Xix Century

The present work aimed to outline the need to investigate different fields of research to interpret the structural behaviour of a monument as complex as the Colosseum. It is shown how defining the numerical models first. then refining them, followed by interpretation of results. is strictly linked with the inforination gathered from historical records and observation of the ~nonumenta s it is today. The study is confined to the area of the Valadier abutment. analysing its state and its seismic behaviour before and after the XIX century restoration using different ilumerical tools, from the elastic modal analysis to the non linear step by step time history direct integration. The procedure comparati\ely evaluates the reliability in the interpretation of the results and identifies future lines or research.

Numerical Modeling of RC Bridges for Seismic Risk Analysis

2016 ◽  
pp. 457-481
Author(s):  
Pedro Silva Delgado ◽  
António Arêde ◽  
Nelson Vila Pouca ◽  
Aníbal Costa
Keyword(s):  
Seismic Response ◽  
Seismic Vulnerability ◽  
Seismic Analysis ◽  
Plastic Hinge ◽  
Probabilistic Approach ◽  
Damage Model ◽  
Experimental Tests ◽  
Concrete Bridges ◽  
Seismic Risk Analysis ◽  
Hinge Model

The main purpose of this chapter is to present numerical methodologies with different complexities in order to simulate the seismic response of bridges and then use the results for the safety assessment with one probabilistic approach. The numerical simulations are carried out using three different methodologies: (i) plastic hinge model, (ii) fiber model and (iii) damage model. Seismic response of bridges is based on a simplified plane model, with easy practical application and involving reduced calculation efforts while maintaining adequate accuracy. The evaluation of seismic vulnerability is carried out through the failure probability quantification involving a non-linear transformation of the seismic action in its structural effects. The applicability of the proposed methodologies is then illustrated in the seismic analysis of two reinforced concrete bridges, involving a series of experimental tests and numerical analysis, providing an excellent set of results for comparison and global calibration.

The effect of materials and design on the reliability of through-glass vias for 2.5 D integrated circuits: a numerical study

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Omar Ahmed ◽  
Chukwudi Okoro ◽  
Scott Pollard ◽  
Tengfei Jiang
Keyword(s):  
Integrated Circuits ◽  
Buffer Layer ◽  
Coupling Effect ◽  
Numerical Study ◽  
Numerical Models ◽  
Thermal Strain ◽  
Content Type ◽  
Mismatch Strain ◽  
Pitch Distance ◽  
Stress Buffer

PurposeThis study aims to investigate the factors responsible for substrate cracking reliability problem in through-glass vias (TGVs), which are critical components for glass-based 2.5 D integration.Design/methodology/approachNumerical models were used to examine the driving force for substrate cracking in glass interposers due to stress coupling during heating. An analytical solution was used to demonstrate how the energy release rate (ERR) for the glass substrate cracking is affected by the via design and the mismatch in thermal strain. Then, the numerical models were implemented to investigate the design factors effects, such as the pitch distance, via diameter, via pattern, via design, effect from a stress buffer layer and the interposer materials selection on the susceptibility to substrate cracking.FindingsERR for substrate cracking was found to be directly proportional to the via diameter and the thermal mismatch strain. When a via pattern is implemented for high-density integration, a coupling in the stress fields was identified. This coupling effect was found to depend on the pitch distance, the position of the vias, and the via arrangement, suggesting a via pattern-dependent reliability behavior for glass interposers. Changing the design of the via to an annular shape or a substrate-cored via was found to be a promising approach to reduce the susceptibility to substrate cracking compared to a fully filled solid via. Also, the use of a stress buffer layer, an encouraging design prospect presented for the first time for TGVs in this study, was found to significantly reduce cracking. Finally, alternative via and substrate materials showed lower tendency for substrate cracking, indicating that the reliability of glass interposers can be further enhanced with the implementation of such new materials.Originality/valueThis study signifies the first attempt to comprehensively evaluate the susceptibility to crack formation in glass interposers during heating. Therefore, this study provides new perspectives on how to achieve a significant potential reliability improvement for TGVs.

scholarly journals A constrained optimization solution for Caughey damping coefficients in seismic analysis

2017 ◽  
Vol 34 (3) ◽  
pp. 682-708
Author(s):  
Danguang Pan ◽  
Chenfeng Li
Keyword(s):  
Seismic Analysis ◽  
Response Spectrum ◽  
Programming Approach ◽  
Content Type ◽  
Practical Applications ◽  
Damping Coefficients ◽  
Modal Damping ◽  
Orthogonality Conditions ◽  
Optimal Damping ◽  
Damping Model

Purpose Extended from the classic Rayleigh damping model in structural dynamics, the Caughey damping model allows the damping ratios to be specified in multiple modes while satisfying the orthogonality conditions. Despite these desirable properties, Caughey damping suffers from a few major drawbacks: depending on the frequency distribution of the significant modes, it can be difficult to choose the reference frequencies that ensure reasonable values for all damping ratios corresponding to the significant modes; it cannot ensure all damping ratios are positive. This paper aims to present a constrained quadratic programming approach to address these issues. Design/methodology/approach The new method minimizes the error of the structural displacement peak based on the response spectrum theory, while all modal damping ratios are constrained to be greater than zero. Findings Several comprehensive examples are presented to demonstrate the accuracy and effectiveness of the proposed method, and comparisons with existing approaches are provided whenever possible. Originality/value The proposed method is highly efficient and allows the damping ratios to be conveniently specified for all significant modes, producing optimal damping coefficients in practical applications.

Rolling bearing seizure and sliding effects on fatigue life

2018 ◽  
Vol 233 (2) ◽  
pp. 339-354 ◽  
Author(s):  
Guillermo E Morales-Espejel ◽  
Antonio Gabelli
Keyword(s):  
Fatigue Life ◽  
Numerical Models ◽  
Rolling Contact Fatigue ◽  
Contact Fatigue ◽  
Damage Mechanism ◽  
Rolling Bearing ◽  
Rolling Contact ◽  
Frictional Stress ◽  
Lubricated Contacts ◽  
Contact Fatigue Life

The effects of kinematic sliding on rolling contact fatigue life have been discussed in many occasions, often with some disregard of the fundamental principles of tribology. In this paper, the authors’ intention is to discuss this issue with a perspective as objective as possible and performing a study on factual and known scientific knowledge, applying tribology modelling and methods. The effects of kinematic sliding of Hertzian contacts are studied from three different standpoints: (1) by analysing the combination of sliding speed and contact pressure giving rise to seizure, that is high instantaneous contact temperatures leading to film collapse, (2) by assessing the possible effects of sliding to surface traction and fatigue, (3) by discussing other possible effects of sliding in heavily loaded lubricated contacts as the concurrent damage mechanism caused by wear and rolling contact fatigue. Throughout the paper, different numerical models are presented and discussed alongside with some experimental data. This approach provides a comprehensive assessment of the various phenomena related to the kinematic sliding of rolling bearings. The different mechanisms involved and the interaction of sliding with the elastohydrodynamic lubricant film, frictional stress, wear and fatigue are discussed, and their significance to the performance of the bearing is qualified.

Stability check of tapered steel beams in fire

2019 ◽  
Vol 10 (4) ◽  
pp. 373-398 ◽  
Author(s):  
Carlos Couto ◽  
Élio Maia ◽  
Paulo Vila Real ◽  
Nuno Lopes
Keyword(s):  
Design Methodology ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Numerical Models ◽  
Design Methods ◽  
Steel Beams ◽  
Content Type ◽  
Design Methodologies ◽  
Accurate Design ◽  
Improved Design

Purpose The purpose of this paper is to assess whether the adaptation to fire of current proposals/design methodologies at normal temperature is capable of producing accurate predictions of resistance for the out-of-plane stability of tapered beams. Design/methodology/approach The adaptation of these methodologies to fire has been done by accounting for the reduction in steel material properties with the temperature. Results were then compared to FEM calculations by performing GMNIA analyses to determine the ultimate strength of the numerical models and to ascertain the validity and accuracy of the adapted methodologies. Findings Although all methodologies produce safe results at normal temperatures, only the general method is recommended for the safety verification at elevated temperatures, although the data points were overly conservative. This investigation demonstrates the need of proper and accurate design methods for tapered beams at elevated temperatures, which should be the subject of future developments. Research limitations/implications The research in this paper is limited to the adaptation of existing room temperature design methods to fire. Therefore, possible assumptions made during the conception of the initial formulae, which may be valid exclusively for 20ºC, may have been disregarded. Originality/value For the time being, design methodologies for the safety check of tapered beams for the case of fire are inexistent. This paper investigates the adaptation of existing room temperature design to the fire situation by providing insights on their accuracy level, as well as on how to proceed. Finally, a safe design methodology for tapered beams in case of fire is provided until improved design methods are developed.

A novel quasi-3D thermodynamic model of oil film bearing with non-Newtonian and temperature-viscosity effects

2017 ◽  
Vol 69 (5) ◽  
pp. 638-644 ◽  
Author(s):  
Feng Liang ◽  
Quanyong Xu ◽  
Ming Zhou
Keyword(s):  
High Speed ◽  
Numerical Models ◽  
Thermal Analyses ◽  
Three Dimensional ◽  
High Rotational Speed ◽  
Content Type ◽  
Oil Film ◽  
Time Consumption ◽  
Simulation Speed ◽  
Viscosity Effects

Purpose The purpose of this paper is to propose a quasi-three-dimensional (3D) thermohydrodynamic (THD) model for oil film bearings with non-Newtonian and temperature-viscosity effects. Its performance factors, including precision and time consumption, are investigated. Design/methodology/approach Two-dimensional (2D), 3D and quasi-3D numerical models are built. The thermal and mechanical behaviors of two types of oil film bearings are simulated. All the results are compared with solutions of commercial ANSYS CFX. Findings The 2D THD model fails to predict the temperature and pressure field. The results of the quasi-3D THD model coincide well with those of the 3D THD model and CFX at any condition. Compared with the 3D THD model, the quasi-3D THD model can greatly reduce the CPU time consumption, especially at a high rotational speed. Originality/value This quasi-3D THD model is proposed in this paper for the first time. Transient mechanical and thermal analyses of high-speed rotor-bearing system are widely conducted using the traditional 3D THD model; however, the process is very time-consuming. The quasi-3D THD model can be an excellent alternative with high precision and fast simulation speed.

Experimental Modal Analysis: Efficient Geometry Model Creation Using Optical Techniques

2006 ◽  
Vol 49 (2) ◽  
pp. 104-113 ◽  
Author(s):  
Steven Pauwels ◽  
Jan Debille ◽  
Jeff Komrower ◽  
Jenny Lau
Keyword(s):  
Modal Analysis ◽  
Numerical Models ◽  
Dynamic Properties ◽  
Real Life ◽  
Geometrical Model ◽  
Experimental Modal Analysis ◽  
Modal Parameter ◽  
Optical Techniques ◽  
Geometry Model ◽  
Modal Parameter Estimation

Experimental modal analysis (EMA) is widely used to characterize the dynamic properties of structures. Recently EMA is being used on more complex structures often involving hundreds of measurement points. Modal analysis results are frequently used in combination with numerical models, imposing higher standards on the quality of the modal parameter estimation and the accuracy of the geometry models. These requirements are often contradictory to the availability of test cells and prototypes. In order to solve this challenge, innovative solutions using optical techniques have been developed that simplify and accelerate the creation of a geometrical model of a test object, while at the same time increase the accuracy of measured coordinates. Industrial applicability of these techniques is proven by a number of benchmarks on real-life structures.

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