scholarly journals DEVELOPMENT OF EVALUATION METHOD FOR DETERMINING THE STRAIN GAUGES OPTIMAL PLACEMENT AND DETERMINING THE STRAIN GAUGES MODE SHAPE SENSITIVITY FACTOR

2017 ◽  
pp. 5-14
Author(s):  
Maria Pivovarova ◽  
◽  
Vadim Besschetnov ◽  
Keyword(s):  
Mode Shape ◽  
Evaluation Method ◽  
Optimal Placement ◽  
Strain Gauges ◽  
Sensitivity Factor ◽  
Shape Sensitivity

A Method to Evaluate the Sensitivity of Aerodynamic Damping to Mode Shape Perturbations

2019 ◽  
Author(s):  
Jing Li ◽  
Suryarghya Chakrabarti ◽  
Wei-Min Ren
Keyword(s):  
Mode Shape ◽  
Gas Turbines ◽  
Fluid Dynamic ◽  
Computational Cost ◽  
Assessment Process ◽  
Mode Shapes ◽  
Shape Sensitivity ◽  
Aerodynamic Damping ◽  
Damped System ◽  
Cfd Analyses

Abstract Turbomachinery blade mode shapes are routinely predicted by finite element method (FEM) programs and are then used in unsteady computational fluid dynamic (CFD) analyses to predict the aerodynamic damping. This flutter stability assessment process is critical for the last-stage blades (LSBs) of modern heavy-duty gas turbines (HDGTs) which can be particularly susceptible to flutter. Evidences suggest that actual mode shapes may deviate from the FEM predictions due to changes in the FEM boundary or loading conditions, effects of the nonlinear friction contacts, and blade-to-blade variations (mistuning), among others. This uncertainty in the mode shape is accompanied by a general lack of knowledge on the sensitivity of the aerodynamic damping to a small change in mode shape. This paper presents a method to perturb a mode shape and estimate the corresponding change in aerodynamic damping in a framework enabled by linear theories and a rigid-body, quasi-3D treatment of mode shapes. This method is of low computational cost and is suitable for use in the preliminary design cycle. The numerical validation and applications of the method are demonstrated on two LSB blades. Results suggest that the mode shape sensitivity can be substantial and may even exceed the change in aerodynamic damping of a frictionally damped system when subjected to various levels of excitation.

Symbiotic Organism Search Algorithm for Optimal Size and Siting of Distributed Generators in Distribution Systems

2017 ◽  
Vol 6 (3) ◽  
pp. 1-28 ◽  
Author(s):  
Tri Phuoc Nguyen ◽  
Vo Ngoc Dieu ◽  
Pandian Vasant
Keyword(s):  
Distribution Systems ◽  
Heuristic Algorithms ◽  
Search Algorithm ◽  
Optimal Solution ◽  
Active Power ◽  
Optimal Placement ◽  
Sensitivity Factor ◽  
Optimal Size ◽  
Symbiotic Organisms Search ◽  
Symbiotic Relationships

This paper presents a new approach for solving optimal placement of distributed generation (OPDG) problem in distribution systems for minimizing active power loss. In this research, the loss sensitivity factor is used to identify the optimal locations for installation of DGs and symbiotic organisms search (SOS) is used to find the optimal size of DGs. The proposed SOS approach is defined as symbiotic relationships observed between two organisms in the ecosystem, which does not need control parameters like other meta-heuristic algorithms. The OPDG problem is considered with two different scenarios including Scenario I for DGs installed at candidate buses to supply only active power to the system and Scenario II for same as Scenario I except that DGs are controlled to supply both active and reactive powers at a 0.85 p.f. The effectiveness of the proposed SOS method has been verified on the IEEE 33-bus and 69-bus radial distribution systems. The result comparison from the test systems has indicated that the proposed SOS is effective to obtain the optimal solution for the OPDG problem.

Experimental Investigation of Mode Shape Sensitivity of an Oscillating LPT Cascade at Design and Off-Design Conditions

2006 ◽  
Author(s):  
Damian M. Vogt ◽  
Torsten H. Fransson
Keyword(s):  
Mode Shape ◽  
Three Dimensional ◽  
High Sensitivity ◽  
Turbine Rotor ◽  
Shape Sensitivity ◽  
Aeroelastic Stability ◽  
Turbine Rotor Blade ◽  
Reduced Frequency ◽  
Lp Turbine ◽  
Bending Modes

The effect of negative incidence operation on mode shape sensitivity of an oscillating low pressure (LP) turbine rotor blade row has been studied experimentally. An annular sector cascade has been employed in which the middle blade has been made oscillating in controlled three-dimensional rigid-body modes. Unsteady blade surface pressure data were acquired at midspan on the oscillating blade and two pairs of non-oscillating neighbor blades and reduced to aeroelastic stability data. The test program covered variations in reduced frequency, flow velocity and inflow incidence; at each operating point a set of three orthogonal modes was tested such as to allow for generation of stability plots by mode recombination. At nominal incidence it has been found that increasing reduced frequency has a stabilizing effect on all modes. The analysis of mode shape sensitivity yielded that the most stable modes are of bending type with axial to chordwise character whereas high sensitivity has been found for torsion-dominated modes. Negative incidence operation caused the flow to separate on the fore pressure side. This separation was found to have a destabilizing effect on bending modes of chordwise character whereas an increase in stability could be noticed for bending modes of edgewise character. Variations of stability parameter with inflow incidence have hereby found being largely linear within the range of conditions tested. For torsion-dominated modes the influence on aeroelastic stability was close to neutral.

scholarly journals A Framework for Optimal Placement of Strain Gauges on Elastic Elements of Force Sensors Using Genetic Algorithms

2020 ◽  
Vol 35 ◽  
pp. 04010
Author(s):  
Sergey I. Gavrilenkov
Keyword(s):  
Elastic Element ◽  
Traditional Approach ◽  
Force Sensor ◽  
Optimal Placement ◽  
Strain Gauges ◽  
Multi Objective Genetic Algorithm ◽  
Design Variables ◽  
Education Tool ◽  
Goal Functions ◽  
And Behavior

This paper presents a digital education tool for learning the specifics and behavior of a multi-objective genetic algorithm (MOGA) used to solve the problem of optimal placement of strain gauges on the elastic element of a force sensor. The paper formulates the problem statement and specifies how this problem can be solved using the MOGA. For the problem, the design variables are the locations of strain gauges and angles at which they are positioned. The goal functions are the output signal of the sensor and the measurement error from bending moments, which can be caused by the off-centric application of load. The solution algorithm is implemented within a framework that can be used to investigate and learn how parameters of MOGA influence its performance. The framework is used to run computational experiments for the given problem to find the optimal placement of strain gauges on the elastic element of a given force sensor. The performance of the MOGA in solving this problem is compared to that of the traditional approach.

scholarly journals Optimal placement of wind turbine in a radial distribution network using PSO method

2020 ◽  
Vol 11 (2) ◽  
pp. 1074
Author(s):  
Yahiaoui Merzoug ◽  
Bouanane Abdelkrim ◽  
Boumediene Larbi
Keyword(s):  
Particle Swarm Optimization ◽  
Wind Turbine ◽  
Radial Distribution ◽  
Distribution Network ◽  
Load Flow ◽  
Optimal Location ◽  
Active Power ◽  
Optimal Placement ◽  
Sensitivity Factor ◽  
Swarm Optimization

<p>The aim of this article is to apply the Particle Swarm Optimization (PSO) method to find the best location for the wind turbine in the radial distribution network. The optimal location is found using the loss sensitivity factor. By respecting the constraints of the active power transmitted in the branches and the limits of the voltages modules for all the nodes. The validity of this method is tested on a 33-IEEE test network and the results obtained are compared with the results of basic load flow.</p>

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