Identifying Real Stiffness Properties of Structural Elements of Adapted Finite-Element Models of Buildings and Structures - Part 1: Problem Setting

2014 ◽  
Vol 670-671 ◽  
pp. 732-735 ◽  
Author(s):  
Pavel I. Novikov
Keyword(s):  
Finite Element ◽  
Mathematical Models ◽  
Dynamic Characteristics ◽  
Finite Element Models ◽  
Structural Elements ◽  
Reliable Analysis ◽  
Adaptive Procedures ◽  
Stiffness Properties ◽  
The Creation ◽  
Problem Setting

The distinctive paper is devoted to problem of identification the dynamic characteristics of mathematical models based on the measured dynamic characteristics of real constructions. It is describes a problem of discrepancy of measured and modeling eigen pairs. It is shown that the problem is systemic. The creation and verification processes of mathematical (finite element) models used in the design constructions need some work and adjustments. For a reliable analysis of the construction ways are suggested to overcome the identified gaps using adaptive procedures.

Identifying Real Stiffness Properties of Structural Elements of Adapted Finite-Element Models of Buildings and Structures - Part 3: Approbation of Experimental Methodology

2014 ◽  
Vol 670-671 ◽  
pp. 742-746 ◽  
Author(s):  
Pavel I. Novikov ◽  
Alexander M. Belostotskiy
Keyword(s):  
Finite Element ◽  
Dynamic Characteristics ◽  
Test Bench ◽  
Experimental Methodology ◽  
Finite Element Models ◽  
Structural Elements ◽  
Defect Identification ◽  
Stiffness Properties

The distinctive paper is devoted to approbation of new defect identification methodology based on the dynamic characteristics of real construction. Mathematically formalized procedure of the methodology is implemented at the test bench. The proposed algorithm identifies a defect. The features of results obtained from the procedure are described.

Identifying Real Stiffness Properties of Structural Elements of Adapted Finite-Element Models of Buildings and Structures - Part 2: Computational-Experimental Methodology

2014 ◽  
Vol 670-671 ◽  
pp. 736-741 ◽  
Author(s):  
Alexander M. Belostotskiy ◽  
Pavel I. Novikov
Keyword(s):  
Finite Element ◽  
Experimental Methodology ◽  
Finite Element Models ◽  
Fe Model ◽  
Wave Method ◽  
Model Adaptation ◽  
Structural Elements ◽  
Defect Identification ◽  
Stiffness Properties ◽  
Standing Wave Method

The distinctive paper is devoted to new defect identification methodology based on dynamic characteristics of real construction. The methodology is founded on mathematically formalized procedure of FE-model adaptation by measured and calculated eigen pairs of dynamic system. Main steps of the methodology are described. Application of the methodology together with standing wave method might allow to identify deviations of stiffness parameters of a real construction facility.

scholarly journals Mathematical Models Based on Transfer Functions to Estimate Tissue Temperature During RF Cardiac Ablation in Real Time

2012 ◽  
Vol 6 (1) ◽  
pp. 16-22
Author(s):  
Jose Alba-Martínez ◽  
Macarena Trujillo ◽  
Ramon Blasco-Gimenez ◽  
Enrique Berjano
Keyword(s):  
Thermal Conductivity ◽  
Electrical Conductivity ◽  
Finite Element ◽  
Mathematical Models ◽  
Dynamic System ◽  
Applied Voltage ◽  
Transfer Functions ◽  
Tissue Temperature ◽  
System Response ◽  
Finite Element Models

Radiofrequency cardiac ablation (RFCA) has been used to treat certain types of cardiac arrhythmias by producing a thermal lesion. Even though a tissue temperature higher than 50ºC is required to destroy the target, thermal mapping is not currently used during RFCA. Our aim was thus to develop mathematical models capable of estimating tissue temperature from tissue characteristics acquired or estimated at the beginning of the procedure (electrical conductivity, thermal conductivity, specific heat and density) and the applied voltage at any time. Biological tissue was considered as a system with an input (applied voltage) and output (tissue temperature), and so the mathematical models were based on transfer functions relating these variables. We used theoretical models based on finite element method to verify the mathematical models. Firstly, we solved finite element models to identify the transfer functions between the temperature at a depth of 4 mm and a constant applied voltage using a 7Fr and 4 mm electrode. The results showed that the relationships can be expressed as first-order transfer functions. Changes in electrical conductivity only affected the static gain of the system, while specific heat variations produced a change in the dynamic system response. In contrast, variations in thermal conductivity modified both the static gain and the dynamic system response. Finally, to assess the performance of the transfer functions obtained, we conducted a new set of computer simulations using a controlled temperature protocol and considering the temperature dependence of the thermal and electrical conductivities, i.e. conditions closer to those found in clinical use. The results showed that the difference between the values estimated from transfer functions and the temperatures obtained from finite element models was less than 4ºC, which suggests that the proposed method could be used to estimate tissue temperature in real time.

scholarly journals Up-to-date mathematical models lines of development of information technologies in the field of numerical methods of structures strength calculations

2018 ◽  
Vol 44 ◽  
pp. 00060
Author(s):  
Vladimir Meleshko
Keyword(s):  
Finite Element ◽  
Numerical Methods ◽  
Mathematical Models ◽  
Information Technologies ◽  
Structural Mechanics ◽  
High Dimensionality ◽  
Finite Element Models ◽  
Systems Of Equations ◽  
Distinctive Features ◽  
Complex Program

In order to carry out reliable calculations of structures adequate to reality, in particular, for taking into account plastic resource, it is necessary to use complex program systems and build finite element models of high dimensionality. This work provides a comparison of different mathematical models, which can be used for numerical analysis. Consideration was given to basic variation principles and methods of calculating structural mechanics. Distinctive features of forming systems of equations of classical methods of structural mechanics and known numerical methods were demonstrated. Possible advantages of methods with respect to accuracy and rate of calculations were revealed. Consideration was given to possible improvements of existing mathematical models in elastoplastic domain. Possible directions of development in the field of engineering methods for calculating strength were proposed.

scholarly journals ASSESSMENT OF CONSIDERATION INFLUENCE OF ELASTIC PROPERTIES IN ROAD-TRAIN SUSPENSION UPON DYNAMIC CHARACTERISTICS OF FLAT-CAR FOR PIGGYBACK TRANSPORTATIONS

2016 ◽  
Vol 2016 (4) ◽  
pp. 179-185 ◽  
Author(s):  
Марина Мануева ◽  
Marina Manueva ◽  
Дмитрий Антипин ◽  
Dmitriy Antipin ◽  
Владимир Кобищанов ◽  
...  
Keyword(s):  
Finite Element ◽  
Elastic Properties ◽  
Dynamic Characteristics ◽  
Finite Element Models ◽  
Real Surface ◽  
Software Complex

The assessment of consideration influence of elastic-dissipative properties in a road-train located upon a flat-car for piggyback transportations at the motion on real surface road imperfections is carried out. The assessment of dynamic characteristics in a flat-car frame is carried out on the basis of finite-element models with the use of “Universal Mecha-nism” software complex.

Analysis on Mechanical Characteristics of Flexible Membranous Disc Coupling

2013 ◽  
Vol 655-657 ◽  
pp. 506-510
Author(s):  
Shang Yang ◽  
Hui Qun Yuan ◽  
Yan Li
Keyword(s):  
Finite Element ◽  
Working Conditions ◽  
Dynamic Characteristics ◽  
Mechanical Characteristics ◽  
Finite Element Models ◽  
Stress Variation ◽  
3D Finite Element ◽  
Harmonic Response ◽  
Design Requirements ◽  
Element Theory

Using the basic finite element theory, 3D finite element models of flexible membranous disc coupling with different disc thickness is built by ANSYS ，and then the dynamic characteristics are analyzed in working conditions. In particular, the analysis of static stress and harmonic response to the thickness of 0.85 model is done for getting the stress variation under a rated condition. The date calculated by dynamic characteristics and stress analysis can satisfy the design requirements. Those researches and analysis provide a theoretical consideration for complex vibration situation of flexible membranous disc coupling and for the improvement and optimization of coupling product.

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