Research on the Vibration Characteristic of Composite Rotor for Halfspeed Nuclear Power Turbine-Generator

2017 ◽  
Author(s):  
Xiu-jin Wang
Keyword(s):  
Natural Frequency ◽  
Nuclear Power ◽  
Geometric Model ◽  
Element Model ◽  
Vibration Characteristics ◽  
Turbine Generator ◽  
Element Analysis ◽  
Large Capacity ◽  
Critical Speeds ◽  
Power Turbine

Shafting is one of the key units of large steam turbine generator set, its dynamic characteristics directly affect the technical level and operation effect of the new type large capacity Turbine-generator unit. The forces acting on the disc and the shaft are complex in operation. A composite rotor has various dynamic characters for a large capacity nuclear power Turbine-generator comparing with general rotor for its different structure. Numerical simulation was carried out to a composite rotor for a large capacity nuclear power T-G set, so as to analyze the influence of different length to diameter ratio on the vibration characteristics of the low pressure rotor and to study the effect of Interference Amount Between disc and shaft by using the three-dimensional finite element analysis in order to meet the requirements of the good vibration characteristics of the rotor. Firstly, the geometric model of the rotor is set up, and then the element model of the shafting is built, finally natural frequency of the rotor is calculated by using the mechanical module. Vibration characters such as the natural frequency and corresponding mode were obtained by analysis of vibration for the disc and shaft. The effect of the interference fit on critical speeds of the rotors are analyzed preliminarily. The results show that critical speeds of T-G rotor vary sensitively with magnitude of interference. (CSPE).

Vibration Characteristics of Rotating Thin Disks—Part I: Experimental Results

2012 ◽  
Vol 79 (4) ◽  
Author(s):  
Ramin M. H. Khorasany ◽  
Stanley G. Hutton
Keyword(s):  
Frequency Response ◽  
Natural Frequency ◽  
Linear Theory ◽  
Lateral Force ◽  
Vibration Characteristics ◽  
Experimental Results ◽  
Rotating Disks ◽  
Critical Speeds ◽  
Applied Forces ◽  
Thin Disks

Analysis of the linear vibration characteristics of unconstrained rotating isotropic thin disks leads to the important concept of “critical speeds.” These critical rotational speeds are of interest because they correspond to the situation where a natural frequency of the rotating disk, as measured by a stationary observer, is zero. Such speeds correspond physically to the speeds at which a traveling circumferential wave, of shape corresponding to the mode shape of the natural frequency being considered, travel around the disk in the absence of applied forces. At such speeds, according to linear theory, the blade may respond as a space fixed stationary wave and an applied space fixed dc force may induce a resonant condition in the disk response. Thus, in general, linear theory predicts that for rotating disks, with low levels of damping, large responses may be encountered in the region of the critical speeds due to the application of constant space fixed forces. However, large response invalidates the predictions of linear theory which has neglected the nonlinear stiffness produced by the effect of in-plane forces induced by large displacements. In the present paper, experimental studies were conducted in order to measure the frequency response characteristics of rotating disks both in an idling mode as well as when subjected to a space fixed lateral force. The applied lateral force (produced by an air jet) was such as to produce displacements large enough that non linear geometric effects were important in determining the disk frequencies. Experiments were conducted on thin annular disks of different thickness with the inner radius clamped to the driving arbor and the outer radius free. The results of these experiments are presented with an emphasis on recording the effects of geometric nonlinearities on lateral frequency response. In a companion paper (Khorasany and Hutton, 2010, “Vibration Characteristics of Rotating Thin Disks—Part II: Analytical Predictions,” ASME J. Mech., 79(4), p. 041007), analytical predictions of such disk behavior are presented and compared with the experimental results obtained in this study. The experimental results show that in the case where significant disk displacements are induced by a lateral force, the frequency characteristics are significantly influenced by the magnitude of forced displacements.

The Finite Element Analysis and Optimization for the Grinder Based on the Joint Surface

2013 ◽  
Vol 281 ◽  
pp. 165-169 ◽  
Author(s):  
Xiang Lei Zhang ◽  
Bin Yao ◽  
Wen Chang Zhao ◽  
Ou Yang Kun ◽  
Bo Shi Yao
Keyword(s):  
Finite Element ◽  
Natural Frequency ◽  
Element Model ◽  
Joint Surface ◽  
Weak Links ◽  
Response Analysis ◽  
Element Analysis ◽  
Static And Dynamic Analysis ◽  
Harmonic Response Analysis ◽  
Grinding Machine

Establish the finite element model for high precision grinding machine which takes joint surface into consideration and then carrys out the static and dynamic analysis of the grinder. After the static analysis, modal analysis and harmonic response analysis, the displacement deformation, stress, natural frequency and vibration mode could be found, which also helps find the weak links out. The improvement scheme which aims to increase the stiffness and precision of the whole machine has proposed to efficiently optimize the grinder. And the first natural frequency of the optimized grinder has increased by 68.19%.

The Finite Element Analysis of a Heavy Semi-Trailer Frame Based on ANSYS

2014 ◽  
Vol 644-650 ◽  
pp. 455-458
Author(s):  
Yao Ye ◽  
Yong Hai Wu
Keyword(s):  
Finite Element ◽  
Geometric Model ◽  
Reference Method ◽  
Element Model ◽  
Element Analysis ◽  
Emergency Braking ◽  
The Finite Element Analysis ◽  
New Type ◽  
Stress And Deformation ◽  
3D Geometric Model

Frame has important effects on the performance of the whole of heavy semi-trailer. A heavy semi-trailer frame is analyzed and researched on in the finite-element way in this article. The frame of 3D geometric model is established by using Pro/E. And it was imported into the Hypermesh to establish frame finite element model. Frame are calculated by using ANSYS solver in bending condition, emergency braking conditions and rapid turn conditions of stress and deformation conditions. The computational tools and methods we used provide the new type of frame and development with a reference method to refer to in this paper.

CT Based Three Dimensional Geometric Model of Cervical Spine

2013 ◽  
Vol 273 ◽  
pp. 588-592
Author(s):  
Zhi Yuan Yan ◽  
Dong Mei Wu ◽  
Li Tao Zhang ◽  
Jun Zhao
Keyword(s):  
Finite Element ◽  
Cervical Spine ◽  
Geometric Model ◽  
Three Dimensional ◽  
Element Model ◽  
Skeletal System ◽  
High Quality ◽  
Element Analysis ◽  
Dimensional Reconstruction ◽  
The Finite Element Model

In order to obtain high-quality analytical results of the finite element model, it is essential to construct a three dimensional geometric model. The paper reconstructed an accurate three dimensional geometric model of cervical spine segments (C4-C7). The process of reconstruction included three-dimensional reconstruction, smooth processing, contour generation, grid generation and fitting surface. Moreover, the result of reconstruction was evaluated ultimately. The model was validated to be smooth and reasonable, and could meet the requirements of finite element analysis. The method is not merely applied to reconstruct the geometric model of the cervical spine. It is a way to construct the model of the skeletal system of the human body.

Use of FEA Software in Evaluating Pump Vibration and Potential Remedial Actions to Abate Resonance in Industrial Vertical Pump/Motor Combinations

2016 ◽  
Author(s):  
Michael Tompkins ◽  
Robert Stakenborghs ◽  
Gregory Kramer
Keyword(s):  
Natural Frequency ◽  
Driving Force ◽  
Nuclear Power ◽  
Power Plants ◽  
Analysis Software ◽  
Element Analysis ◽  
Screw Pump ◽  
Twin Screw ◽  
Remedial Actions ◽  
Motor Structure

Reactor recirculation motor generator lube oil twin screw pumps are commonly found in nuclear power plants and throughout industry. In a vertical mounting configuration in which the electric motor is bolted atop the twin screw pump in an unsupported manner the natural frequency of the pump/motor structure can be quite low, resulting in damaging vibration. When a structure’s natural frequency coincides at or near the operating speed, or multiple thereof, a phenomena known as resonance can occur. Resonance can occur when a driving force, in this case minor imbalances in either the motor or pump, begins to vibrate and excite the structure resulting in greatly amplified levels of vibration. In this paper, finite element analysis software is utilized to first calculate the natural frequency of the pump/motor structure, and then potential modifications are modeled to determine their impact on eliminating harmful resonance.

scholarly journals Finite Element Analysis of Adolescent Mandible Fracture Occurring during Accidents

2018 ◽  
Author(s):  
Jarosław Żmudzki ◽  
Karolina Panek ◽  
Grzegorz Chladek ◽  
Marcin Adamiak ◽  
Paul Lipinski
Keyword(s):  
Finite Element ◽  
Geometric Model ◽  
Element Model ◽  
Cortical Layer ◽  
Mandibular Fractures ◽  
Total Force ◽  
Element Analysis ◽  
Mandible Fractures ◽  
Distributed Forces ◽  
Sport Accidents

The paper aims in assessing risks of mandible fractures consequent to impacts or sport accidents. The role of the structural stiffness of mandible, related to disocclusion state, is evaluated through numerical simulations using the finite element method (FEM). It has been assumed that the quasi-static stress field, due to distributed forces developed during accidents, could explain the common types of mandibular fractures. Geometric model of adolescent mandible was built, upon the basis of medical imaging, in CAD software with distinction between cortical layer and inner spongy bone. The finite element model of disoccluded mandible was next created. Mandibular condyles were supposed jammed in the maxillary fossae. The total force of 700 N, simulating an impact on mandible, has been sequentially applied in three distinct areas: centrally, at canine zone and at the mandibular angle. Clinically most frequent fractures of mandible were recognized through the analysis of maximal principal stress and maximal principal strain fields. Mandibular fracture during accidents can be analyzed at satisfactory level using linear quasi-static FE models for designing protections in sport and transport. The proposed approach can be improved by introducing more realistic interactions between condylar processes and fossae.

Temperature Calculation on Phase Lead Connecting Structures of 1100MW Generator Stator Parallel Rings

2011 ◽  
Vol 383-390 ◽  
pp. 3040-3045
Author(s):  
Yan Fei Wei ◽  
Le Qi ◽  
Ting Shan Wang ◽  
Jian Ping Wang ◽  
Zhe Long Xian ◽  
...  
Keyword(s):  
Nuclear Power ◽  
Operation Performance ◽  
Turbine Generator ◽  
Field Coupling ◽  
Temperature Calculation ◽  
Phase Lead ◽  
Power Turbine ◽  
Calculation Results ◽  
Calculation Software ◽  
Generator Stator

The temperature rise of generator components has a great impact on operation performance for large turbine generator. In this paper, applying the general FE calculation software-ANSYS, with a sequential electromagnetic-thermal field coupling calculation method, temperature calculation on phase lead connecting structures of 1100MW nuclear power turbine generator parallel rings is presented. The calculation results could offer a basic analysis to optimize the design of the generator.

Finite Element Analysis of Air Cooler Used in Nuclear Power Station

2011 ◽  
Vol 194-196 ◽  
pp. 1982-1985
Author(s):  
Shao Qing Hu ◽  
Yong Li Zhang
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Nuclear Power ◽  
Element Model ◽  
Load Case ◽  
Power Station ◽  
Element Analysis ◽  
Operating Load ◽  
Air Cooler ◽  
The Finite Element Model

According to the characteristics of cooler, the finite element model of air cooler is established using ANSYS f software. The force and moment are acted on nozzles using MPC184 element. The first natural frequency is given. Then the stresses of cooler under normal operating load case and under accidental load case are calculated respectively. The stresses of nozzles and foot were checked according to RCC-M specification and meet the requirements.

Finite Element Simulation of Grinding Stress for a Fiber Optic Connector (Ceramic Ferrule)

2005 ◽  
Vol 297-300 ◽  
pp. 2327-2332 ◽  
Author(s):  
Chang Min Suh ◽  
Ki Sang Jung
Keyword(s):  
Finite Element ◽  
Fiber Optic ◽  
Geometric Model ◽  
Element Model ◽  
Grinding Force ◽  
Element Analysis ◽  
Element Simulation ◽  
Dimensional Finite Element ◽  
Input Variables ◽  
High Level

Ceramic ferrule that is a major part of the optic connectors requires a high level of precision in a grinding chamfer. After the grinding chamfer, there is a problem in that the subsurface damages cannot be removed. The objective of this study was to analyze the grinding force and the associated stress generated in a ceramic ferrule during cylindrically grinding chamfer using Finite Element Analysis (FEA). A two-dimensional finite element model was constructed with the grinding parameters and the mechanical properties of the ferrule as input variables. The size of the geometric model was the same with the ceramic ferrule. The experimental results achieved by the SEM photograph were compared with those from the FEM. The FEM results were in correlation with those of the experiments.

scholarly journals The Potential Influence of Tree Crown Structure on the Ginkgo Harvest

Forests ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 366
Author(s):  
Yan Xuan ◽  
Linyun Xu ◽  
Guanhua Liu ◽  
Jie Zhou
Keyword(s):  
Natural Frequency ◽  
Economic Value ◽  
Mechanical Vibration ◽  
Element Model ◽  
Fruit Trees ◽  
Vibration Characteristics ◽  
Damping Coefficient ◽  
Additional Energy ◽  
Frequency Model ◽  
Crown Structure

Ginkgo biloba L. has significant health benefits and considerable economic value, but harvesting the fruit is highly labor-intensive. Mechanical vibration harvesting has been shown effective in harvesting various fruit types. In the study of vibration harvesting, the research on the vibration characteristics of fruit trees focuses on the natural frequency (resonance frequency), model, and damping coefficient, which are the main factors affecting the vibration characteristics of trees. But field harvesting experiments have shown that the tree structure may have an impact on the vibration characteristics of the fruit tree and the efficiency of mechanical harvesting. In addition, the research on the damping coefficient of fruit trees is mainly low-frequency damping, and the relevant results cannot be applied to the actual vibration harvesting frequency range. Applying a natural frequency with low damping coefficient to excite a tree can reduce additional energy dissipation. This study explored the influence of ginkgo crown structure on the vibration characteristics and the law of damping changes with frequency. After counting 273 ginkgo trees, two typical ginkgo crown structures, monopodial branching and sympodial branching, were selected to be analyzed for vibration spectrum and damping coefficient. The vibration models for different crown-shaped ginkgo trees were simulated to analyze the vibration state at different frequencies. For sympodial branching ginkgo trees, the consistency of natural frequencies at different branches was better than monopodial branching ginkgo trees. The finite element model analysis shows that monopodial branching ginkgo trees have mainly partial vibrations at different branches when vibrating at high frequencies. The high-frequency vibrations in sympodial branching reflect the better overall vibration of the canopy. The damping coefficients for the two crown types decreased with the increase in frequency. The monopodial branching damping coefficient was 0.0148–0.0298, and the sympodial branching damping coefficient was slightly smaller at 0.0139–0.0248. Based on the test results, the sympodial branching ginkgo tree has better vibration characteristics. The results indicate that controlling the crown structure of fruit trees to be sympodial branching by pruning may help improve the overall vibration characteristics of fruit trees.

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