The present work considers an alternative solution for a complex configuration of rotor discs by applying Galerkin Method. The theoretical model consists of elastic shaft carrying number of discs and supported on number of journal bearings. The equation of motion was discretized to finite degree of freedom in terms of the system generalized coordinates. The various effects of the dynamical forces and moments arising from the bearing, discs and shaft were included. Rayleigh beam model is used for analyzing the shaft while the discs are considered rigid . The validity and convergence of the present analysis was carefully checked by comparing with the Finite Element solution. An example of rotor consists of three different size discs and supported by two journal bearing was considered for the numerical solution .The results shows good agreements between the two methods ,where the maximum error not exceeds 5%. The convergence test showed that using few modes (not more than 6) are sufficient for the accurate analysis. The forward and backward whirl was investigated experimentally .The experimental results of a two discs rotor ,show a reasonable agreement where the maximum error not exceeds 11%. The unbalance response, Cambpell diagram, orbit response were plotted .The effects of geometry, disc sizes , location and arrangement on the unbalance response and natural frequencies of three discs rotor were further investigated .

In this paper an attempt to provide a single degree of freedom lumped model for fluid structure interaction (FSI) dynamical analysis will be presented. The model can be used to clarify some important concept in the FSI dynamics such as the added mass, added stiffness, added damping, wave coupling ,influence mass coefficient and critical fluid depth . The numerical results of the model show that the natural frequency decrease with the increasing of many parameters related to the structure and the fluid .It is found that the interaction phenomena can become weak or strong depending on the depth of the containing fluid .The damped and un damped free response are plotted in time domain and phase plane for different model parameters It is found that the vibration free response is still sinusoidal for weak FSI coupling ,however for strong coupling it behaves as modulated periodic response .To justify some of the theoretical aspects such as; the effects of the fluid density and the interact shape on the natural frequency an experiment was conducted .The results of the experiment shows a good agreement with the theory where the error is not exceeded 7%.

Whey is a liquid residual from cheese production with high protein content. The high protein content causes whey to be used in the formulation of functional ingredients for food and beverage products. such as formula milk, sports supplements, and pharmaceuticals. The goal of the study was to determine the effect of types and fillers concentration on the quality of whey protein products using a spray dryer. The study involved the optimization of types and concentrations of different fillers on whey protein production and quality analysis by chemical and organoleptic tests. This study used a randomized block design with two factors. Factors A (type of filler) and B (concentration of filler) consisted of three levels, with two replications. Factor A was A1 = maltodextrin, A2 = pectin, and A3 = gum arabic, while factor B was B1 = 1%, B2 = 1.5% and B3 = 2%. Maltodextrin, pectin, and gum Arabic at 1% concentration resulted in the best whey protein through the spray drying process. Organoleptic test results with hedonic and hedonic quality obtained optimum results in the treatment of 1% maltodextrin filler. Therefore 1% maltodextrin could be applied in the whey protein production. Meanwhile, the analysis of chemical quality showed that the content of water, ash, protein, fat, and carbohydrates were 4.4%; 7.76%; 11.23%; 3.58%, and 73.82%, respectively.

This work deals with studying the possibility of introducing new material into the spring manufacturing and study the properties of this spring and the load-carrying capacity when it is facing compression load. Then, specifying the application that this new composite spring could be used for. One of the applications of springs are in the suspension system, and the primary demand that the designers of automobiles are looking for is improving fuel efficiency, which may be related to the weight of the vehicle. In this research, the steel spring has been replaced by glass and carbon fibers composite with polyester resin as a matrix material. Theoretical analysis has been conducted, and numerical analysis of spring was performed using ANSYS WORKBENCH to simulate the spring under axial compression load. A comparison between the the theoretical and numerical deflection results has been made to predict the best material that can be used for replacement the steel spring. The second part of the research is the selection of materials and the utilized mold in the manufacturing process of the composite helical compression spring by using fibers, it was found that carbon fiber spring has results near to steel spring with stiffness 5.66 and steel 5.49 and glass composite spring 5.018 and carbon composite deflection was less than the glass composite deflection.

In this work it had been focused on the possibility of replacement of steel spring in suspension system by fiber reinforced polymer composite that is responsible for light weight of spring which leads to reduces the weight of vehicle and improve fuel efficiency. This type of spring used in motor cycles, light weight vehicle. The design will be simulated by ANSYS workbench. Then, E-Glass fiber has been used to fabricate helical compression spring of 40% fiber volume fraction of glass. with polyester resin. The deflection of glass reinforced composite spring is more than steel spring but within permissible limit. weight of composite spring is reduced by 57% than of steel.

Abstract A below knee (BK) prosthesis is a device used to compensate for missing limb segments in patients with BK amputations as an aid for locomotive and other daily activities It consists of three main parts: socket, shank, and artificial foot. The shank is merely a shaft of a suitable length to serve as a frame structure to transfer biomechanical forces between the socket and foot. In traditional BK prostheses, the shank is made from rigid metallic or composite material tube (Teflon), while in the current work, a modified version is suggested with internal stiffness and damping characteristics to act as energy storage and shock absorber. A mathematical model was thus employed to analyse the impact behaviour from walking gait, and the main parameters studied were the effective mass of impact, loading rate, and knee pre-swing angular velocity. The modified prosthesis was tested with a BK amputation patient and compared with a traditional prosthesis in force platform and treadmill tests. The results showed some improvement in patient gait parameters; at stance phase, it smoothed the GRF curve; at heel strike, both the effective mass of impact and loading rate increased by 16% and 22%, indicating good impact reduction, and at pre swing, it increased the initial flexion angle and angular velocity by 13% and 15%, respectively, enhancing the swing phase.

Buckling analysis of mechanical structures is essential to insure stability under loading .Critical load of buckling refer to the maximum load can be withstood without losing of stability and avoid a catastrophic damage due to the collapse of columns .Improving of mechanical properties spatially those related with elastic behaviors of materials can lead to improving buckling since it can be raised the value of critical load . Nanotechnology is one of the modern methods which makes significant effects on the mechanical properties of materials. In the field of composite materials this technology leads to valuable improvements for the favorite properties. In this regard Nano composite materials are paid a spatial attention in research for the last decade. The main aim of the present work is to investigate the effect of Nano carbon weight fraction on buckling of the composite plate. Five samples of Nano composite plates were prepared and fabricated for experimental investigations .The plate samples are combined of woven reinforcement fiber and polyester matrix with Carbon .The weight fraction of Nano additives are 0 %, 0.5%, 1%, ,1.5 and 2%, of resin materials weight. To provide homogenous composite an ultrasonic homogenizer is utilized. The experimental work include buckling test for different Nano plates samples with simply supported at two ends and free at the other .Finite Element analysis was achieved via ANSYS R15.0 with proper elements ,meshing ,boundary condition and static analysis .It is found that increasing of Nano carbon weight ratio tends to increase critical load of buckling ,the maximum buckling load is at 2% wt ratio and the experimental results shows fair validation for the numerical analysis where the maximum error dos not exceeded 15% .

Liquefied Petroleum Gas (LPG) are commonly used in many practical applications as a storage container for gasses under pressure such as oil refinery, production and fuel stations. Design of LPG vessels must meet strict requirements to insure safety and prevent environmental hazard ASME codes for pressure vessel are a general roles for design and testing for all the available vessels ranging from huge nuclear to small fuel tanks. For specified vessel the designer must has a spatial experience to involve the right criteria. In ASME codes there existed many types of end heads for pressure vessels such as; Torispherical, Elliptical 2:1 and Hemispherical. Selection of head type is left as an option for the designer. In this work an attempt is made to investigate the effect of using three types of end heads on the design of inservice horizontal. Moderate pressure vessel using ASME codes. The studied model represents a practical case in which a horizontal (18 bar) LPG vessel fabricated in Heavy Engineering Equipment State Company (HEESC) Dura Refinery -Baghdad Iraq. The design is based on ASME: SEC.VIII div.1 which is suitable for moderate pressure as classified by ASME The results are compared with two commercial design software namely; COMPRESS and PV Elite. It is found that using of hemispherical head can reduce design thickness up to 51.5% as compared with other heads which results economic and light weight vessel, so it is recommended in to be used at HEESC and using the commercial software lead to higher design thickness for all head types. Copyright © 2018 International Energy and Environment Foundation All rights reserved.

The delamination is defect which leads to reduce the mechanical properties of composite structure, as a results different mechanical behavior of the structure can be altered. Since the buckling behavior is one the most important mechanical behavior of composite structure for many engineering application. Then, it is necessary to investigate the effect of various delamination parameters, such as size (dimensions of delamination) and position (at x, y, and zdirections) on the buckling characterization of composite plate structure. The present study includes evaluating of the critical buckling load by using two techniques. First, experimental techniques, by testing the plates manufactured samples (including delamination) with buckling test, As well as, evaluating the mechanical properties of materials which are necessary to be used as input data for numerical techniques. Second, numerical technique by using Ansys program as an application of finite element method. A comparison between the results of the two methods are made to show the validity of these techniques. A model of composite plate combined from glass woven reinforcement fiber and epoxy resin materials with six layers is fabricated and tested, the plate is clamped supported from two edge and free supported from other edges. The comparison between the results shows an acceptable agreement between the experimental and numerical analysis where the error is not exceed about (10.7%). Finally, the results show that the delamination leads to reduce the buckling strength of composite plate structure, with the increasing of the delamination size and as the location is approached the point at which the maximum bending moment occurs. Index Term— Delamination Effect, Delamination Buckling, Composite Buckling, Delamination Size Buckling.

Pressure vessels are the heart of plants and oil refineries stations. In many engineering applications such vessels can be subjected to periodic loading either internally due to the charging and discharging process or externally due to the excitation from other nearby components such as pumps, compressors or from seismic. So that in spite of a good design according static assumption it may be critical in dynamics. In this work a horizontal pressure vessel with accessories subjected to liquefied petroleum gas pressure LPG is considered. Three models of different head types are investigated herein namely; Deep torispherical, Elliptical 2:1 and Hemispherical. The design and material selections are chosen as per ASME. For practical service many accessories are attached to the vessel such as manhole, supports, inlet and outlet opining. Finite Element method via ANSYS R18.2 is introduced for the numerical analysis. The fatigue life in case of fully reversed cyclic loading are estimated and located. Vibration characteristics such as mode shapes and natural frequencies for the lowest five modes are evaluated and compared. It is found that the fatigue life can be increased as higher as 180% for hemi- spherical head as compared with deep torispherical head pressure vessel and the lowest four natural frequencies are nearly identical for all models, however significant change observed in the fifth natural frequency.

In this work, a mathematical model for investigating the fitting of self-suspension Below Knee (BK) prosthesis was attempted. The model is based on linkage kinematic and kinetics analysis of the residual limb segments as well as the stresses analysis at the stamp-socket interfacing. The prosthesis socket and the residual limb are approximated as combined two thick cylinders with shrinkage at interface. Lames equations of hoop and longitudinal stresses are applied with specific boundary conditions. The main parameters investigated in this model are; locomotive speed, swing phase of gait cycle, socket material, skin status and prosthesis weight. A map is constructed to investigate the effect of these parameters on prosthesis suspension fitting. The theoretical results are checked experimentally by using force platform and treadmill tests. A patient wearing BK prosthesis is participate in the experiments. KINOVA video analysis program is used for analyzing gait cycle. MATLAB Rb2013a program is used for solving the theoretical equations and plotting the results. It was found that; the suspension of the socket decrease as the walking speed increase within 1.5 to 12 m/s, skin sweating and dirty reduces the suspension force and increasing the risk of socket slippage, The more dangerous region of slip in socket occurs at midswing for the most of walking speeds and increasing the shrinkage fitting increase the suspension action. Copyright © 2018 International Energy and Environment Foundation All rights reserved.

A new approach for evaluating the flutter instability boundaries based on the analytical solution of the equation of motion of cantilever pipes conveying fluid has been attempted. This approach leads to a simple transcendental equations form which the critical speed of flutter instability and the associated natural frequencies of cantilever pipes can be determined for any pipe parameters. The stability and critical natural frequencies maps can be simply constructed. The results of the presented approach are carefully checked with published results. The presented results showed very good agreements. Copyright © 2017 International Energy and Environment Foundation All rights reserved.

Evaluating the natural frequencies of multi- span beams with elastic supports play a major role in vibration designing and optimizing of many structures such as bridges, railways ,pipes and so on The continuity of the boundary conditions ,state space and numerical methods are normally used to investigate the vibration characteristics of such structures .Unfortunately ,such methods lead to high size matrix in dealing with the boundary value problem as the number of spans increase. In the present work, the problem is solved analytically by using Modal Analysis techniques in which the continuous system is discreteized to finite degree of freedoms in terms of the generalized coordinates A proper shape function are employed for describing the system dynamical behavior and satisfying the boundary conditions .In the present method the size of the resulting Eigen matrix depends on the number of mode chosen regardless of the number of spans. With this method wide variety of support configurations can be treated. The validly and convergence of the present method for calculating the natural frequencies is carefully checked by comparing with the exact values for two-span beams with different boundary conditions . It is found that using only (5) modes for the assumed solution gives only 2% error for two span simply supported and free ends beam , however for clamped ends the error is 8% .The present method is further checked by comparing with the Finite Element method the results show good agreements where the error is not increases 1% .The results of the natural frequencies of up to (10) equal and unequal spans beams under different boundary conditions and support stiffness are presented .The results showed that the natural frequencies can be highly controlled by proper choosing of the structure parameters and support stiffness.Keywords: , , , ,

In MATLAB System Identification SID refers to the method for estimating the system transfer function from experimental tests by using computer software so in this work the SID method is employed for analyzing practical structure for crankshaft. The validity of this method is firstly checked by applying it on beam model under boundary condition (simply support) where the required parameters for this simple system are evaluated in two ways. First theoretically by using Modal analysis approach and second experimentally by using SID method. From comparing the results, it is found that; the accuracy of using SID method is within acceptable limits, where the error is not exceeded 6.7% for case of simply support. Then the method is extended for using for the crank shaft it is found that the transfer function parameters at the mid-section are increased as compared with the crank ends. Copyright © 2017 International Energy and Environment Foundation All rights reserved.

In this work a general dynamic response of two-story building due to earthquake is investigated .A spatial case of two degree mass-spring–damper random vibration model is employed .The base excitation acceleration is represented according to the well- knownregression model  by Kanai –Tajimi in term of the power specturm density  (PSD). The transfer function between the ground an the roofs are evaluated assuming transverse modes of vibration.A case study of typical two symitrical story building manufactored from reinforced concret and steel is investigated.The vibration parameters such as effective mass and stiffiness and damping are calculated according  to the ACI 318-11 code.The natural frequncies , mode shape and transfer functions are calculated and plotted.The PSD acceleration at the roofs are evaluated from which the mean and standared diviation of the random accelration are found .The drift at the walls is calculated and compared with the allowable limits recommended by IBC 2015 .It is found that the probability of the bulding to be safe is  between (13.74 -7.35)% for the first story and (8.7 - 1.67) % for the second.

The modern development in prosthetics field demand the evaluation of the dynamical behavior and automatic control .The key process in the design and implement of these devices is the determination of the model parameters inherited with the transfer function .In such complicated structures it is so difficult to evaluate transfer function analytically ,however experimental approaches can serve as a simple and effective tool for estimating transfer function and model parameters .In this regard computer software such as Matlab is used .System Identification SID refers to the method for estimating the system transfer function from experimental tests by using computer .In the present paper; SID method is employed for analyzing below-knee prosthesis leg .In order to simulate with the practical requirement for design and evaluation ,two phases of human gait are considered ,namely; swing phase and single support of stance phase .The validity of this method is firstly checked by applying it on clamped-clamped beam model where the required parameters are evaluated and compared theoretically (via modal analysis) and experimentally (via System identification) .It is found that ; the error in estimating the transfer function parameter of beam is not exceeded 6% . Then the transfer function of the prosthesis are estimated for two phases of gait cycle .It is found that; the estimated transfer function of the prosthesis leg is highly affected by the phase type of gait cycle , where ;the natural frequency highly increases, the static gain decrease for support phase as compared with the swing phase ,however the damping ratio does not affected .

As immersed rotors vibrate in a viscous media such as fluid, a considerable amount of damping may be generated due to the interaction phenomena between the rotor components and the fluid media. Such damping is depending on many factors such as; fluid drag, fluid friction, turbulence, vortex and so on. Immersed rotors find their application in many engineering fields such as Marines machines, gear box, turbine and pumps. In the present work, a mathematical model is attempted to investigate the dynamical behavior immersed rotor. The model takes into account the effects of the most rotordynamic parameters, namely; fluid drag, damping and stiffness of bearing, unbalance and gyroscopic effects of the attached disc, and elastic bending and internal damping of rotor shaft. Four types of fluid are employed as a fluid immersing media which are; Air, Water, SAE 20 and SAE 40 oils. The experimental apparatus includes a sample rotor with single disc and plastic fluid container. Two proximate sensors are employed for measuring the unbalance response and orbits shapes under different rotor speeds, and discs size and locations. Modal analysis is employed for solving the governing equation of vibration motion. To check the validity of the mathematical model the theoretical results are compared with the experimental results. It is found that; the theoretical results are in a good agreement with the experimental ones, where the maximum error is not exceeded (6.8 %), and that; the fluid damping can highly reduce the peak amplitude of the unbalance response (up to 60 %) however, it has slight effect on the critical speeds which are highly affected by the size and location of the attached disc. Copyright © 2016 International Energy and Environment Foundation All rights reserved.

In many classes of problems of elastic systems such as gyroscopic and circulatory systems stability investigations are being conducted .The concept of a "stability boundary" arising in connection with multiple loading parameters is used for stability investigation. The concept is extended to analyze stability of conservative pipes conveying fluid since they are regarded as gyroscopic systems. In this approach the pipe system is discretized to a two –degree of freedom by using Galarkin projection. The solution of the Eigen-value problem leads to the characteristic equation describing the parameters -frequency relationship .By plotting the root locus of these characteristic equation the main stability features such as stability, buckling and flutter instability and destabilization has been investigated graphically .The validity of this approach was tested by comparing it with the other published methods The results gave good agreements. The effect of the fluid parameters such as fluid velocity, fluid pressure and pipe-fluid mass ratio on the pipe stability are also investigated. The results showed that the mass ratio has a major effect on stability behaviors since the sequence of stability can be dramatically changed whereas ,the fluid pressure showed slight effect since the stability sequence is not altered , for wide range of the fluid velocities .

Belt is a traveling continuous system.Such a system can subjected to a static divergence and parametric instability. This depend on whether the system parameters are constant or varying with the time ,respectively .In this paper ,instability problem is solved analytically .Bolotin method is used to evaluate the boundaries which separate the stable and instable regions.The present solution is checked with another solution available in the literature where the Variation principle is used .The results showed a good agreement where the maximum error do not exceed 5%. The effect of belt tension and transmitting speed on stability and natural frequency are studied .The results show that increasing belt tension can improve both buckling and parametric instability. Whilst, increasing the speed or its mean value is limited to critical values to avoid buckling or parametric instability, respectively.

Conservative pipes conveying fluid such as pinned-pinned (p-p), clamped–pinned (c-p) pipes and clamped-clamped (c-c) lose their stability by buckling at certain critical fluid velocities. In order to experimentally evaluate these velocities, high flow-rate pumps that demand complicated fluid circuits must be used. This paper studies a new experimental approach based on estimating the critical velocities from the measurement of several fundamental natural frequencies .In this approach low flow-rate pumps and simple fluid circuit can be used.Experiments were carried out on two pipe models at three different boundary conditions. The results showed that the present approach is more accurate for estimating the critical velocities of p-p and c-p pipes. However, for c-c pipes it was not so unless a higher flow rate is used.