فهرست مطالب

International Journal of Engineering
Volume:30 Issue: 5, May 2017

  • Transactions B: Applications
  • تاریخ انتشار: 1396/03/10
  • تعداد عناوین: 23
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  • M. J. Taheri Amiri, F. R. Haghighi, E. Eshtehardian, O. Abessi Page 627
    In the last decade, theory of constraint application in project management lead to make a new approach for project scheduling and control as a critical chain. In this paper, a multi-objective optimization model for multi-project scheduling on critical chain is investigated. The objectives include time, cost and quality. In order to solve the problem, a Simulated Annealing algorithm is developed and then analyzed to investigate the effect of each objectives. The number of activities in each project is not considered the same. Time, cost and quality value are calculated by solving the proposed algorithm and then the total utility amount is obtained. Sensitivity analysis is performed based on various amount of each objective weights. Then the effect of objectives weight variation is investigated on utility function value. In addition the results show that the proposed algorithm are able to solve problem optimally in large scale.
    Keywords
    Keywords: Multi objective, Multi project scheduling, Critical chain, Simulated annealing
  • V. Sai Giridhar Reddy, V. Ranga Rao Page 636
    In spite of broad improvements in construction technology, cement is still stayed as binding material for construction purposes. Cement industries are the main sources for the contribution of carbon dioxide (co2) into the atmosphere. So, there is a need to use new materials as binders (green binders) in substitute for cement, which leads to reducing the production of cement. In this study, fly ash and ground granulated blast furnace slag (GGBS) are used as source materials. Since fly ash and GGBS are industrial wastages which are non-renewable in nature, quarry dust is used as the partial replacement that is 50% in weight with fine aggregate. Soluble activators like Sodium hydroxide (NaOH) and Sodium silicate (Na2SiO3) of 12M are used instead of water in the ratio of 1:2.5. Different mix proportions are considered in this study such as F80G20, F70G30 and F60G40. These mix proportion results were compared with conventional concrete of M20. The results were drawn for different strength tests such are Compressive strength test, Split Tensile strength test and Flexural strength test. From the results it is concluded that F60G40 mix has high Compressive strength, Split Tensile strength and Flexural strength compared to remaining mixes along with conventional concrete.
    Keywords: Fly ash, GGBS, Quarry dust, Soluble Activators, Ambient Curing, Green binders.
  • T. Raghunadha Reddy, B. Vishnu Vardhan, P. Vijayapal Reddy Page 643
    Author profiling is a text classification technique, which is used to predict the profiles of unknown text by analyzing their writing styles. Author profiles are the characteristics of the authors like gender, age, nativity language, country and educational background. The existing approaches for Author Profiling suffered from problems like high dimensionality of features and fail to capture the relationship between the features. In this work, a new document weighted approach is proposed in order to address the problems in existing approaches. In this approach, the term weight measure is used to assign suitable weight to the terms and these term weights are aggregated to compute the document weight. The classification model is generated with these document weights for predicting profiles of the text. The proposed approach and existing approaches are experimented on reviews domain with different classifiers. The accuracies of the proposed approach for gender and age prediction are promising than existing approaches.
    Keywords: Author Profiling, Gender prediction, Age prediction, Term weight, Document weight, Classifiers
  • J. Bhaskara Rao, J. Beatrice Seventline Page 652
    Surface roughness measurement is widely used to estimate the quality of the product during manufacturing processes. It has a great importance in manufacturing fields such as ceramic tiles, glass, and iron. Many are using surface profile-meter with a contact stylus to measure the surface roughness of work piece. In the stylus method, a stylus is moved along the surface and the vertical movement of the stylus is recorded to measure surface roughness. This method has the disadvantage that work piece surface may damage due to direct contact between the surface and the stylus. In this paper, we propose a novel technique to find the roughness parameters of a surface by using image processing techniques like Contrast stretching and Bi-cubic interpolation techniques of image enhancement. In these techniques, firstly the surface image of the work pieces is acquired using the digital camera and it is pre-processed in order to remove noise and then image enhancement is done followed by parameters analysis. The roughness parameters such as average surface roughness (Ra), Maximum valley profile depth (Rv (Valley)), Highest peak (Rp (Peak)), Root-mean-square (rms) roughness (Rq (rms)) were determined using above techniques. The results obtained by the both methods are tabulated and compared.
    Keywords: Surface Roughness, Wiener filter, Contrast stretching, Adaptive Median filter, Bi-cubic Interpolation.
  • P. Kalpana, K. Mani Page 659
    Feature selection is a pre-processing technique used for eliminating the irrelevant and redundant features which results in enhancing the performance of the classifiers. When a dataset contains more irrelevant and redundant features, it fails to increase the accuracy and also reduces the performance of the classifiers. To avoid them, this paper presents a new hybrid feature selection method using information gain and symmetric uncertainty. The proposed work uses median based discretization for converting the quantitative features into qualitative one, information gain in finding the relevant features and symmetric uncertainty to remove the redundant features. As the proposed work uses both relevance and redundant analyses the predictive accuracy of the Naive Bayesian classifier has been improved. Further the efficiency and effectiveness of the proposed methodology is analyzed by comparing with other existing methods using real-world datasets of high dimensionality.
    Keywords: Irrelevant, Redundant, Median Based Discretization, Information Gain, Symmetric Uncertainty, Accuracy, Naive Bayesian Classifier
  • M. Niaz Azari, M. Samami, S. M. Abedi Pahnehkolaei Page 668
    This contribution deals with an optimal design of a brushless DC motor, using optimization algorithms, based on collective intelligence. For this purpose, the case study motor is perfectly explained and its significant specifications are obtained as functions of the motor geometric parameters. In fact, the geometric parameters of the motor are considered as optimization variables. Then, the objective function has been defined. This function consists of three terms i.e. losses, construction cost and the volume of the motor which should be minimized simultaneously. Three algorithms i.e. cuckoo, genetic and particle swarm have been studied in this paper. It is noteworthy that, cuckoo optimization algorithm has been used for the first time for brushless DC motor design optimization. A comparative study between the mentioned optimization approaches shows that, cuckoo optimization algorithm has been converged to optimal response in less than 250 iterations and its standard deviation is , while the convergence rate of the genetic and particle swarm algorithms are about 400 and 450 with standard deviations of and , respectively for the case study motor. The obtained results show the best performance for cuckoo optimization algorithm among all mentioned algorithms in brushless DC motor design optimization.
    Keywords: BLDC motor, Cuckoo algorithm, Objective function, Optimal motor design
  • A. Dehzangi, A. R. Ghaffari, S. Kakooei, M. Ghasemi, F. Saadati, H. Soleimani Page 678
    In this work, we use Drude-Lorents model description to study the radiation of a charged particles moving in a homogeneous dispersive medium. A suitable quantized electromagnetic field for such medium is utilized to obtain proper equations for energy loss of the particle per unit length. The energy loss is separately calculated for transverse and longitudinal components of the filed operators. The calculations show that the longitudinal component of the field operators contributes in electron radiation, when dielectric function is exceedingly dependent on the frequency. It is also shown that when the dispersion is not included, the obtained equations are in a good agreement with previous results. For negligible dispersion, the contribution of the field’s longitudinal component tends to zero and at the end the results are in agreement with Ginsberg’s calculations. This calculation can reveal a development for the fields’ quantization for permeable dielectric background medium.
    Keywords: Cherenkov radiation, quantum computing, Drude-Lorents model, homogeneous dispersive medium
  • J. Mohamadiyan, G. Shams- Khoramabadi, S. A. Mussavi, B. Kamarehie, Y. Dadban Shahamat, H. Godini Page 684
    This study is focused on removing toxic aniline from aqueous solutions using advanced oxidation process by UV/ peroxy disulfate. In this study, the effect of various parameters including pH (3-9), the level of radiation (ultraviolet 30 watt lamp, number 2-5), peroxy disulfate dose (0.02 – 0.08 mol/l) and the initial concentration (20 – 100 mg/l) at different contact times (10 – 60 min) on the efficiency of aniline removal in a laboratory reactor with UV lamps and in a batch mode, was studied. The results of this study showed that the efficiency of removing aniline decreased by increasing and decreasing pH from 5 (maximum efficiency = 66.6%, at pH= 5) and also by increasing the concentration of pollutant. But by increasing the amount of radiation and peroxy disulfate dosage (0.02 to 0.08 mol/l, the process efficiencies will be 46 to 82.8% after 60 min, respectively), the efficiency increased. The efficiency of removing aniline in the combined process of UV/peroxy disulfate increased significantly by using peroxy disulfate and UV, individually (96%). In the process, the efficiency of removing aniline from aqueous solution was due to the production of UV effect on Peroxy disulfate and the production of strong oxidizing radicals. Therefore, due to the high performance and low cost raw materials, this process can be used for removing resistant compounds from industrial sewages.
    Keywords: aniline, peroxydisulfate, ultraviolet, degradation, advanced oxidation
  • K. Khlie, A. Abouabdellah Page 691
    Lean health care is one of new managing approaches putting the patient at the core of each change. Lean construction is based on visualization for understanding and prioritizing imporvments. By using only visualization techniques, so much important information could be missed. In order to prioritize and select improvements, it’s essential to integrate new analysis tools to achieve a good understanding of what the value is for the patient, analyze their requirements/expectations/needs and prioritize them in light of strong evidences and detailed measures. In that perspective, this paper intends to integrate lean thinking, data mining and six sigma improvement process methods with the goal to develop a lean health care driving methodology. The proposed methodology allows a better understanding of the patient perception of quality based on a Kano questionnaire. Questionnaire results are then analyzed using data mining tools to extract useful information. Finally, six sigma approach is followed to improve the quality of health care services and maximize the patient satisfaction. The main outcome of the study is that the first priority concerns the availability of physicians and health products, followed by the reduction of waiting time and minimization of errors related to prescriptions and diagnostics. The use of the six sigma approach on the medication circuit allows improving those three criteria.
    Keywords: Healthcare service, Lean, Data mining, Kano model, questionnaire, public hospital
  • A. Noroozi, M. Mahdavi Mazdeh, M. Rasti-Barzoki Page 700
    This paper develops Order Acceptance for an Integrated Production-Distribution Problem in which Batch Delivery is implemented. The aim of this problem is to coordinate: (1) rejecting some of the orders (2) production scheduling of the accepted orders and (3) batch delivery to maximize Total Net Profit. A Mixed Integer Programming is proposed for the problem. In addition, a hybrid meta-heuristic algorithm is developed. For a quick exploration around a solution, a Local search is proposed. Two simple heuristics for initial population and a heuristic for batching are proposed. Besides, data is generated to evaluate the performance of algorithms and compare with each other based on comprehensive experiments.
    Keywords: Order Acceptance, Integrated Production-Distribution, Batch Delivery, Genetic Algorithm, Particle Swarm Optimization
  • G. Moslemipour, R. Tavakkoli-Moghaddam Page 710
    In this paper, to cope with the stochastic dynamic (or multi-period) problem, two new quadratic assignment-based mathematical models corresponding to the dynamic and static approaches are developed. The product demands are presumed to be dependent uncertain variables with normal distribution having known expectation, variance, and covariance that change from one period to the next one, randomly. In the proposed models, time value of money and the decision maker’s attitude about uncertainty are also considered. The models are verified and validated by performing statistical, robustness and stability analyses carried out by using design of experiment and benchmark methods. In addition, the effect of dependency of product demands and interest rate on the total cost function of the proposed models has also been investigated. The dynamic programming algorithm, which is coded in Matlab, is used to solve the models. The main conclusions are as follows: (i) the dynamic layout behaves like static layout in the case of low facility rearrangement cost; (ii) unlike the static layout, the robustness and stability of the dynamic layout depend on the facility rearrangement cost; (iii) the decision maker’s attitude about uncertainty affects the robustness of each of the dynamic and static layouts; (iv) considering non-zero interest rate leads to increase in the total cost over the range of uncertainty; and (v) regarding both the dynamic and the static layouts, the effect of dependency of product demands on the total cost is a function of the decision maker’s defined percentile level.
    Keywords: Dynamic facility layout, Quadratic assignment, Uncertainty, Dynamic programming
  • R. Soofifard, M. Gharib Page 720
    Risks are natural and inherent characteristics of major projects. Risks are usually considered independently in analysis of risk responses. However, most risks are dependent on each other and dependent risks are rare in the real world. This paper proposes a model for proper risk response selection from the responses portfolio with the purpose of optimization of defined criteria for projects. This research has taken into account the relationships between risk responses; especially the relationships between risks, which have been rarely considered in previous works. It must be pointed out that not considering or superficial evaluation of the interactions between risks and risk responses reduces the expected desirability and increases project execution costs. This model is capable of optimization of different criteria in the objective function based on the proposed projects. Multi-objective Harmony Search (MOHS) is used to solve this model and the numerical results obtained are analyzed.
    Keywords: Risk response, Project risk management, Risk interactions, MOHS algorithm
  • S. M. Mousavi Page 729
    Selecting the most suitable alternative under uncertainty is considered as a critical decision-making problem that affects the success of organizations. In the selection process, there are a number of assessment criteria, considered by a group of decision makers, which often could be established in a multi-level hierarchy structure. The aim of this paper is to introduce a new hierarchical multiple criteria group decision-making (HMCGDM) approach in hesitant fuzzy setting based on the concept of compromise solutions. Motivated by hesitant fuzzy sets, Hamming distance measure is utilized in the process of the proposed hierarchical method, namely HF-HMCGDM, and also hesitant fuzzy weighted averaging operator is used to aggregate the judgments of experts or decision makers. Firstly, for assessing weights of criteria, a hesitant fuzzy hierarchical weighting method is developed. To rank the possible alternatives, a new hesitant fuzzy extension of the classical compromise solution method is then proposed. Furthermore, a case study in the new product ideas problem from the recent literature is provided to illustrate the proposed HF-HMCGDM approach, and finally a comparative analysis is given to demonstrate the capability.
    Keywords: Hesitant fuzzy sets, Hierarchical decision making, Compromise solution method, Multi-criteria group decision-making, New product selection problems
  • S. Ebrahimnejad, H. Gitinavard, S. Sohrabvandi Page 739
    Information technology (IT) outsourcing has been recognized as a new methodology in many organizations. Yet making an appropriate decision with regard to selection and use of these methodologies may impose uncertainties and risks. Estimating the occurrence probability of risks and their impacts organizations goals may reduce their threats. In this study, an extended analytical hierarchical process method is tailored based on interval-valued hesitant fuzzy information to assess the risks in IT outsourcing. In the proposed approach, the weight of each decision maker is implemented in process of the proposed method by considering the concept of simple additive weighting method to decrease the judgment errors. In addition, the opinions of each decision maker about the risks of IT outsourcing under the conflicted attributes are aggregated in final step of the proposed procedure to reduce the data loss. Indeed, this paper proposes a new extended interval-valued hesitant fuzzy final aggregation analytical hierarchical process by considering the decision maker's importance. Finally, an adopted case study in ISACO corporation as the largest spare parts deliverer in Iran is considered to indicate the process implementation of the proposed approach. In this respect, the risks and their factors in the domain of IT outsourcing are identified based on experts’ judgments. Therefore, the achieved ranking results indicate that the proposed approach could deal with group decision-making problem as a reliable manner.
    Keywords: Analytical hierarchy process, Multi-attribute group decision making problem, Interval-valued hesitant fuzzy setting, Pairwise comparisons
  • M. Nouri Koupaei, M. Mohammadi, B. Naderi Page 749
    Nowadays, flexible manufacturing system (FMS) is introduced as a response to the competitive environment. Scheduling of FMS is more complex and more difficult than the other scheduling production systems. One of the main factors in scheduling of FMS is variable time of taking orders from customers, which leads to a sudden change in the manufacturing process. Also, some problems are created in production system such as waste, earliness and tardiness costs, and increase inventory. In this paper, a part of flexible manufacturing system where products are produced in two stages and in multiple repositories, is known as a bottleneck. In this study, a mathematical model for scheduling of this problem considering the limitations of the production system such as flow rate and output reservoirs, variable time order entry, waste resulting from the cessation of production, and the storage capacity of reservoirs is developed. Then, the proposed model has been solved by GAMS software. Results confirm the validity of the proposed model.
    Keywords: Flexible manufacturing system, Earliness, tardiness penalties, Mathematical modeling, Scheduling
  • S. Javanmardi, H. Hosseini-Nasab, A. Mostafaeipour, M. Fakhrzad, H. Khademizare Page 758
    Developing the infrastructures for preventing non-communicable diseases is one of the most important goals of healthcare context in recent years. In this regard, the number and capacity of preventive healthcare facilities as well as assignment of customers to facilities should be determined for each region. Besides the accessibility, the utility of customers is a determinative factor in participation of people in the offered programs. In this paper, a service network design problem is studied such that the utility function is incorporated in the objective function, and the constraints set. The travel distance is deterministic and demand elasticity results in congestion delays. After simplifying the nonlinear model, a bi-level optimization algorithm is proposed to obtain the optimal solution. Computational results assure the efficiency of the developed algorithm. Finally, the capability of the model is represented by discussing a case study of locating preventive healthcare facilities in Yazd, Iran.
    Keywords: Network Design Problem, Preventive Healthcare, Utility, Elastic Demand, Congestion
  • Mahmoud M. M. Page 768
    The present work aims at reducing the friction of rubber soles sliding on ceramic floorings. Fitting bored cylindrical protrusions with different diameters on rubber soles was proposed. Experiments were carried out to evaluate the performance of the proposed protrusions in increasing friction coefficient at dry and contaminated floorings. It was found that, at dry sliding, friction coefficient significantly increased up to maximum then decreased with increasing the number of holes. The highest friction values were observed for 1.5 mm diameter holes, while the lowest values were displayed by 3.0 mm diameter holes. In the presence of water on the flooring, it was shown that as the hole diameter increased, the volume of the water leaked out the contact area increased. The detergent layer formed on the contact area caused drastic friction decrease. The highest friction value did not exceed 0.13 which confirmed the severity of walking in the presence of detergent. When sand particles covered the sliding surfaces, the effect of hole diameter was much less than the number of holes. When oil contaminated the sliding surfaces, friction coefficient significantly increased at single hole protrusion. The effect of single hole was more pronounced than the effect of hole diameter due to the strong adhesion of oil into the rubber and ceramic surfaces. Water/oil contaminated ceramic flooring showed the highest friction coefficient (0.26) at single hole of 1.5 mm diameter. Further increase in the number of holes decreased friction values. Presence of sand in oil contaminated ceramic flooring did not increase the friction coefficient, where the highest value did not exceed 0.2. Sliding against water/oil dilution and sand contaminated ceramic flooring represented relatively higher friction values. Protrusions perforated by three holes of 2.5 mm diameter showed the highest friction followed by single hole of 3.0 mm diameter and four holes of 1.5 mm diameter.
    Keywords: Friction coefficient, rubber cylindrical protrusions, holes, ceramic flooring
  • M. Zolfaghari Page 775
    This paper presents a modified form of the Walker-Anderson (W-A) model for analyzing high velocity penetration of an eroding projectile into a concrete target in which the W-A model is improved by incorporating calculations for the plastic flow field of concrete in terms of its compressibility and strain rate sensitivity under severe pressure. With the changes to and calculations of plastic field in concrete targets, equations of penetration were rearranged. Solution of equations gives penetration depth, penetration velocity, projectile rod velocity and length of a projectile instantaneously. Results of this analysis were compared with experiments performed by authors of this paper`. Experiments were performed in order to test eroding long-rod (9≤L/d≤11) penetration into semi-infinite concrete targets at high impact velocities (650 (m/s) Normal 0 false false false EN-US X-NONE AR-SA
    Keywords: Eroding projectile, concrete resistance, analytical model, long rod, penetration
  • A. Zahedi Nejad, M. Rad, M. Khayat Page 785
    Design and manufacturing of a high performance micro-hydro-kinetic turbine is discussed in the present paper. The main goal is manufacturing an equipped experimental model of hydro-kinetic turbine with highest energy absorption from water current. A multi-shape ducted turbine comprised of a multi-part diffuser was manufactured that can be converted to many experimental models for studying various diffuser enhancing effects. Turbine's rotor included a three-blade axial propeller and a mixed six-blade propeller with high power coefficient. Simple experiments on propeller were performed for flow visualization, torque measurement and illustrating dynamic balance at high speed rotation in air and water. Important data for design and manufacturing of duct and rotor components that led to safe structure and balanced the rotor at high speed rotations were discussed. For dynamic simulation of turbine, a user-defined function was developed for ANSYS-FLUENT software that collects integration data and solves rotor's dynamic equation in one-degree of freedom motion. Many stable dynamic simulation methods for coupling with transient one-dimensional flow around one-degree of freedom propellers were proposed and the numerical results were validated against full CFD data.
    Keywords: Duct, Dynamic simulation, Fabrication, Hydro-kinetic turbine, Propeller test
  • G. H. Majzoubi, Mohammad Zaheri Page 791
    Kevlar is a type of aramid fibers which is characterized by high strength to low weight ratio. This material is widely used in bulletproof vests and helmets, in which it creates a barrier to projectiles to protect specific objectives, laminated tubes and pressure vessels, etc. In this study the ballistic behavior of Kevlar /epoxy composite and Kevlar fabric is investigated. The results showed that Kevlar fabrics were more resistant against projectiles. Tensile and punch tests revealed that although the Kevlar/Epoxy composite enjoys higher strength, undergoes lower deformation than Kevlar fabric. The results also indicated that the failure mechanism of Kevlar fabric was quite ductile whereas the presence of epoxy in Kevlar/epoxy changed the failure mechanism from ductile to brittle in the form of plugging in ballistic tests. Finally, the ballistic behavior of the Kevlar fabric was simulated by ABAQUS finite element software and the results were validated by the experiment.
    Keywords: Kevlar fiber, Finite element simulation, Kevlar, Epoxy, Ballistic
  • Sandip S. Patel, J. M. Prajapati Page 800
    Proper selection of material in manufacturing firms is a vital role of designer depending upon the different era of application. The material selection problem is very complex and challenging task today. Erroneous cull of material frequently leads to astronomically immense cost involution, and finally drives towards unfortunate component or product breakdown. Thus, the designer necessitates discovering and culling the felicitous materials with concrete functionalities in order to obtain the desired output with least cost involution and definite applicability. It is an intension for simple, logical and rational methods or statistical implements to direct decision makers while considering number of cull attributes and their interrelations. This paper introduce a way to work out the material selection problem by one of the most Multi-Criteria decision making (MCDM) approaches in which ranking of the best material is computed using the multi-objective optimization on the basis of ratio analysis (MOORA) method.
    Keywords: Material, Attributes, Interrelation, MCDM, MOORA
  • S. Mosalman, S. Rashahmadi, R. Hasanzadeh Page 807
    Various applications of nanocomposites were a good motivation to start a study on this wide spreading field of science. Current research is an investigation on incorporating different percentages of TiO2 nanoparticle as reinforcement to a base material which here is poly methyl methacrylate (PMMA). In this study various percentages of TiO2 (0.5, 1 and 2 wt%) were added to pure PMMA and effect of this combination on the mechanical properties of produced composite by performing several tests was investigated and compared to the base material. For producing samples, materials were compounded by melting compounding method using a twin screw extruder followed by injecting molding process. SEM images showed that almost all percentage of TiO2 nanoparticles have been mixed suitably through base matrix. Rockwell hardness R, impact and tensile tests were carried out on all specimens. Almost all of the results illustrated that combination of TiO2 nanoparticle with PMMA, improves mechanical properties of composite. The results also indicated amazing effect of TiO2 nanoparticles on improvements of impact and flexural strengths. Highest recorded impact strength showed 229% increase in samples containing 2 wt% nanoparticles compared to the base material.
    Keywords: PMMA, Nanocomposite, TiO2 nanoparticle, Impact strength, Flexural strength
  • M. K. Amirinejhad, M. Ranjbar, M. Karimkhany Page 814
    Centrifugal compressors produce high pressure ratio and rotate at speeds. So, a tiny unbalance can produce severe vibration. In this paper, effects of impeller gap on rotor vibration in a high speed centrifugal compressor is investigated. For this purpose, a numerical and experimental analysis are carried out. The moving reference frame method in FLUENT software is used for modeling of geometries. Then, the motion of rotation components is introduced using UDF (User-Difined-Function) writing in C software and Define CG Motion macro. By using cloud points, three-dimensional geometry model of blades of this compressor is prepared. Finally, two-dimensional geometry of diffuser is added to blades and the final geometry is presented. Fluid flow inside the centrifugal compressor with and without considering blades vibration is studied. The numerical and experimental analysis of power spectrum density to determine the dominant vibration frequency cause of horizontal and vertical forces exerted on the compressor is studied. Results show that the dominant frequency of vibrations of forces exerted on the compressor is in the range of 9800 Hz, that is in good agreements with those reported by earlier researchers. Also, the main reason of centrifugal compressors shaft vibration is static and dynamic unbalance in shaft and other components of the compressor. In other words, the forces exerted on compressors blades do not affect the centrifugal compressor vibration. In the numerical studies, distribution of pressure, temperature, velocity and velocity vectors at different times are studied. Horizontal and vertical forces exerted on the compressor is represented. The mass flow rate of the compressor output for different cases of A/G ratio is presented and does not depend on amplitude of vibrations.
    Keywords: compressor vibration, high speed compressor, rotor vibration, airflow distribution