DYNAMIC RESPONSE EVALUATION OF A FRAMED TYPE TURBO-GENERATOR FOUNDATION INCORPORATING DYNAMIC MODULUS AND OPERATING SPEED VARIATIONS

2004 ◽  
Vol 04 (03) ◽  
pp. 379-402 ◽  
Author(s):  
N. LAKSHMANAN ◽  
K. MUTHUMANI ◽  
N. GOPALAKRISHNAN ◽  
K. SATHISH KUMAR

Framed type foundation structures supporting turbo-generator machinery in a power plant have stringent vibration limits to ensure proper functioning of turbine generators without any breakdown. Current dynamic analysis methodology for such dynamically sensitive structures involves modal synthesis considering a single value of operating speed for the machinery and a uniform dynamic modulus for the frame material, which cannot be realized in site conditions. Such variations in the dynamic modulus across the whole structure and running speed of the machinery during normal operation have a profound impact on its dynamic performance which may result in alarmingly increasing amplitudes leading to subsequent breakdown of the machinery. A new methodology is outlined that combines the effects of the two variations by way of considering an enhanced range of speeds on either side of the operating speed for the modal synthesis process. This study shows the effects of variations in the dynamic modulus and operating speed on the peak dynamic response of a typical framed turbo-generator foundation structure. The modal synthesis process adopted in the study includes the significant modes in the sub-resonant range and a band of modes around the operating speed to obtain the peak response of the framed structure.

Author(s):  
Jahangir Rastegar ◽  
Dake Feng

In general, mechanical systems with closed-loop mechanisms can achieve significantly higher operating speeds as compared to open-loop mechanisms such as robots performing identical tasks. In this brief paper, the reason for the superior dynamic performance of closed-loop mechanisms as compared to open-loop mechanisms performing identical tasks is shown to be the inherent dynamic response limitations of the actuation devices in open-loop dynamic systems. Several examples are provided.


2021 ◽  
Vol 9 (1) ◽  
pp. 96-103
Author(s):  
Ruba Asim Hamza ◽  
Amged Osman Abdelatif

Sudan is one of the developing countries that suffers from a lack of electricity, where the national electrification rate is estimated at 38.5%. In order to solve this problem, it is possible to use renewable energy sources such as wind energy. Beside many aspects to be considered at the design of wind turbine foundations, more attention should be given to the geotechnical part. There are many types of foundations for wind turbines. The foundation must satisfy two design criteria: 1) It should be safe against bearing failure in soils under design loads and settlements during the life of the structure must not cause structural damage; 2) In addition to static loads, wind turbine foundations loads are extremely eccentrically and the loading is usually highly dynamic. Therefore, the selection of foundation type should consider these two criteria taking into account the nature and magnitude of these loads. This paper presents a review of different types of wind turbine foundations of focusing on on-shore wind turbine foundation types and the dynamic response of wind turbine. The paper also demonstrate experimentally the dynamic response of the wind turbines using wind tunnel facility test on a scaled model.  


2012 ◽  
Vol 184-185 ◽  
pp. 170-174
Author(s):  
Lei Zhang ◽  
Cun Yun Pan ◽  
Xiao Chong Wang ◽  
Hao Deng ◽  
Hu Chen

Rotary Piston Engine is a new kind of rotary engine. To analyze the dynamic character of the valve system, kinematics equations are established using dynamical method. Dynamic response of the valve is studied by calculating the outcome using numerical method.FFT analysis is applied here to analyze the response curve. The result shows that the Valve Train covers the basic need, but the dynamic performance of the system still could be improved.


Author(s):  
Ping-Hsun Lin ◽  
Hsiang Hsi Lin ◽  
Fred B. Oswald ◽  
Dennis P. Townsend

Abstract This paper presents procedures for designing compact spur gear sets with the objective of minimizing the gear size. The allowable tooth stress and dynamic response are incorporated in the process to obtain a feasible design region. Various dynamic rating factors were investigated and evaluated. The constraints of contact stress limits and involute interference combined with the tooth bending strength provide the main criteria for this investigation. A three-dimensional design space involving the gear size, diametral pitch, and operating speed was developed to illustrate the optimal design of spur gear pairs. The study performed here indicates that as gears operate over a range of speeds, variations in the dynamic response change the required gear size in a trend that parallels the dynamic factor. The dynamic factors are strongly affected by the system natural frequencies. The peak values of the dynamic factor within the operating speed range significantly influence the optimal gear designs. The refined dynamic factor introduced in this study yields more compact designs than AGMA dynamic factors.


2014 ◽  
Vol 945-949 ◽  
pp. 2680-2684
Author(s):  
Ai Qin Huang ◽  
Yong Wang

Direct drive volume control (DDVC) electro-hydraulic servo system has many advantages compared to the valve control system. However, its application scopes were restricted by its poor dynamic performance. To study the reason for the low dynamic response, mechanical model of DDVC electro-hydraulic servo system is established. Structure parameters influencing the dynamic performance are analyzed. To optimize the structure parameters, the methodology of orthogonal experiment is presented. The selection of factors and levels of the experiment and the choice of the evaluation index are also revealed. The proposed methodology is carried out by simulation software and an optimal configuration is obtained. The dynamic response of the DDVC system with the optimal parameters is simulated. The results show that the dynamic performances are improved. The cross-over frequencyincreases from 0.0046 rad/s to 0.0442 rad/s, and the rise time Tr decreases from 488.6s to 47.90s.


Author(s):  
Javier Freire ◽  
Esteve Codina ◽  
Munir Khamashta

Understanding the behavior of system with flexible elements is increasingly important in modern day technology. Reducing the mass of machine elements leads to a remarkable improvement in dynamic performance. However, a loss of precision also occurs with such an increase in flexibility. In order to arrive at a better understanding of systems with flexible elements, we are investigating the particular behavior of a hydraulic servo driven rotating flexible beam with the aim of obtaining a methodology that could be applied to a real application. To investigate this behavior, a set of models has been developed. In this paper, a theoretical model, using classical modal analysis methodology, is presented. The flexible beam is modeled in a standard way and the hydraulic servo drive is modeled as a boundary condition. Only normal modes will be investigated. This approach allows considering the servo proportional constant and the cylinder mass. It will be show that the servo proportional constant has low influence in the system eigen frequencies. The theoretical model predictions are validated experimentally.


Author(s):  
Yongming Cheng ◽  
Tao Qi

A riser is a fluid conduit from subsea equipment to surface floating production systems such as spars, TLPs, and semi-submersibles. It is a key component in a drilling and producing system. Drilling risers include the applications in marine drilling (low pressure) and tie-back drilling (high pressure). This paper discusses drilling riser design and analysis for a deepwater application. This paper first discusses the configuration of marine drilling and tie-back drilling risers. It then presents the drilling riser design procedure and analysis methodology. The riser design and analysis cover the riser tensioner setting, marine operation window, strength and fatigue, etc. A marine drilling riser example is used in the paper to demonstrate the design and analysis for a deepwater application. This paper shows the dynamic strength analysis results for the riser. It then identifies governing locations for the riser design. A tie-back drilling riser example is also provided to illustrate its global dynamic performance. This paper finally discusses the design and analysis challenges of a drilling riser for a deepwater application.


Author(s):  
Jianli Zuo ◽  
Jianjun Wu ◽  
Ping Li ◽  
Shenjian Su

The physical model of a high-speed vertical rotating machine was taken as the example. The motion differential equations of the rotor system were established by the Lagrange equation and numerically solved by the Wilson-θ method. The whirling characteristics of the rotor excited by the base’s harmonic motions have been analyzed. The whirling directions are different between the rotor’s upper and lower ends. And the whirling characteristics of the rotor vary with the frequency of the base’s motion. Besides, there exists such a region of the rotor’s rotary speed, in which the whirling characteristics and amplitudes of the rotor system are relatively steady, so the aseismic tests at a certain lower speed can be done to examine the aseismic capability of the rotor system at operating speed.


2012 ◽  
Vol 166-169 ◽  
pp. 720-724
Author(s):  
Bai Sheng Wang ◽  
Dong Hui Cao ◽  
Ying Wu Yang ◽  
Chun Xiao Xu ◽  
Hua Jun Qian

A space numerical model about 1000MW turbo generator foundation of a power plant is established by ANSYS software, meanwhile analyzing the model’s vibration characteristics and response under the turbo generator working conditions. According to the existing norms, optimizing the foundation based on the linear displacement amplitude control, furthermore researching the corresponding dynamic on the optimized foundation for guidance to structural design.


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