Active Vibration Control Analysis of Cantilever Pipe Conveying Fluid Using Smart Material

In this paper, experimental and simulation studies in active vibration of smart cantilever pipe conveying fluid have been presented to investigate the open and closed loop time responses. A program to simulate the active vibration reduction of stiffened pipe with piezoelectric sensors and actuators was written in the ANSYS workbench and  Parametric Design Language (APDL). This makes use of the finite element capability of ANSYS and incorporates an estimator based on optimal linear quadratic control (LQR) schemes to investigate the open and closed loop time responses. The procedures are tested by active control for free and forced vibrations of piezoelectric smart cantiliver pipe conveying fluid. Harmonic excitation is considered in the forced vibration. Experiments have been done to verify with simulations. Smart pipe consists of aluminum pipe surface glued piezoelectric patches of MIDÉ QuickPack QP20W transducers. An experimental result is acquired by LabVIEW programs. It is found the location of the piezoelectric actuator has in influence on the response of the cantilever pipe. The displacement increases when the actuators are moved closer to the clamped. This is due to the higher strain developed near the clamped . The control performance  decrease with increasing  the flow velocity due to increased  coriolis force.The better performance of control occur at minimum velocity(Q=10L/min) and location1 of actuator, the maximum reduced the displacement response from +8mm to 1mm. Keywords: Active vibration control, LQR, cantilever pipe, smart structure, Smart material, piezoelectric

An Analytical Investigation of Thermal Buckling Behavior of Composite Plates Reinforced by Carbon Nano Particles

The research used analytical and numerical methods to test thermal buckling activity for a composite plate structure with a range of Nano fractions. Experimental program with mechanical properties for the Nano composites were carried out and have been validated from previous work. In addition, both mechanical and thermal expansions were tested from previous work experimentally and used in numerical and analytical methods by the Nano composite. The general motion equation for thermal buckling load was derived and then, the results were compared with the numerical results. The analysis showed that the average outcome error was not greater (2.49%). Ultimately, the results showed that the thermal effect results in a buckling of Nano particle strengthening (1%) volume fraction for the adjusted structure of the plate leads to increase thermal buckling strength (63,4%). This achievement modified a high thermal buckling strength with low percentage of Nano volume fraction compared to the previous work in this field

A Suggested Analytical Solution For Laminated Closed Cylindrical Shells Using General Third Shell Theory (G.T.T.)

Transient solutions will be developed for laminated simply supported closed cylindrical shells subjected to a uniform dynamic pressure at the outer surface of the cylinder. These solutions are obtained by using General Third Shell Theory (G.T.T.). Rectangular pulse, triangular pulse, sinusoidal ulse and (ramp-constant) load-time varying functions are studied and the required equilibrium equations are developed. The central deformation and principle stresses are investigated for different cross-ply laminates

FLUTTER SPEED LIMITS OF SUBSONIC WINGS

Flutter is a phenomenon resulting from the interaction between aerodynamic and structural dynamic forces and may lead to a destructive instability. The aerodynamic forces on an oscillating airfoil combination of two independent degrees of freedom have been determined. The problem resolves itself into the solution of certain definite integrals, which have been identified as Theodorsen functions. The theory, being based on potential flow and the Kutta condition, is fundamentally equivalent to the conventional wing-ection theory relating to the steady case. The mechanism of aerodynamic instability has been analyzed in detail. An exact solution, involving potential flow and the adoption of the Kutta condition, has been analyzed in detail. The solution is of a simple form and is expressed by means of an auxiliary parameter K. The use of finite element modeling technique and unsteady aerodynamic modeling with the V-G method for flutter speed prediction was used on a fixed rectangular and tapered wing to determine the flutter speed boundaries. To build the wing the Ansys 5.4 program was used and the extract values were substituted in the Matlab program which is designed to determine the flutter speed and then predicted the various effects on flutter speed. The program gave us approximately identical results to the results of the referred researches. The following wing design parameters were investigated skin shell thickness, material properties, cross section area for beams, and changing altitude. Results of these calculations indicate that structural mode shape variation plays a significant role in the determination of wing flutter boundary

Improving Fatigue Life of Bolt Adapter of Prosthetic SACH Foot

In this research an analysis for improving the fatigue behavior (safety factor of fatigue) of non- articular prosthetic foot (SACH) in the region (Bolt Adapter).The laser peening was carried to the fatigue specimens to improving the fatigue properties of bolt’s material. The tests of mechanical properties and fatigue behavior were carried for material that the bolt manufacture from it, a region where the failure occur and inserted of these properties to the program of engineering analysis (Ansys) to calculate the safety factor of fatigue. The results showed that the safety factor after hardening by laser is increased by 42.8%

A STUDY OF THE EFFECT OF SEMI-ANGLE OF CONE ON THE VIBRATION CHARACTERISTICS OF CYLINDRICAL-CONICAL COUPLED SHELL STRUCTURE

In this work, the effect of variation of semi-angle of the conical part on the vibration characteristics of cylindrical-conical coupled structure is investigated. The shell is made of polyester resin reinforced by continuous E-glass fibers. The case is analyzed experimentally and numerically for orthotropic shell structures. The experimental program is conducted by exciting the fabricated structure by an impact hammer and monitoring the response using an attached accelerometer for different semi-angles of the conical part. Software named SIGVIEW is used to perform the signal processing on the acquired signal in order to measure the natural frequencies and the corresponding mode shapes. The numerical investigation is achieved using ANSYS (Finite Element software) which was verified by the experimental results. Good agreement is achieved when comparing the experimental and numerical results. The maximum deviation in results was found to be (5.9%). The maximum relative nodal rotational and translational amplitudes associated with the first normal mode of the orthotropic and isotropic shells are noted for the structure of semi-angle of cone of 45o

Nonlinear Dynamics of Thick Composite Laminated Plates Including the Effect of Transverse Shear and Rotary Inertia

In this work, a suggested analytical solution for nonlinear dynamic analysis of (fiber-reinforced) composite laminated thick plate is developed by using first-order shear deformation theory (FSDT). A computer program was built for this purpose for antisymmetric cross-ply and angle-ply, simply supported thick laminated plate and the developed equations are solved by using (MATLAB V.7) program. The finite-element solution is also adopted using (ANSYS V.8) package, to confirm the analytical results. The results presented show the effect of plate thickness-to-side ratio (h/a), aspect ratio (a/b), number of layers (N), the degree of orthotropic ratio (E1/E2), fiber orientation, boundary conditions, lamination scheme, and the effect of shear deformation and rotary inertia on the thick laminated plate

Free Vibration Analysis of Composite Cylindrical Shell Reinforced with Silicon Nano-Particles: Analytical and FEM Approach

Previous research presented the effect of nanomaterials on the mechanical properties of composite materials with various volume fraction effects; in addition, their research presented the effect of nanomaterials on the same mechanical characteristics for a composite plate structure, such as vibration and thermal buckling behavior. Therefore, since the use of shell structures is for large applications, it is necessary to investigate the modification of the vibration characteristics of its design with the effect of nanomaterials and study the influence of other reinforced nanoparticle types on its features. Therefore, in this work, silicon nanoparticles were selected to investigate their effect on the vibration behavior of a shell structure. As a result, this work included studying the vibration behavior by testing the shell structure with a vibration test machine. In addition, after manufacturing the composite material shell with various silicon volume fractions, the mechanical properties were evaluated. In addition, the finite element technique with the Ansys program was used to assess and compare the vibration behavior of the shell structure using the numerical technique. The comparison of the results gave an acceptable percentage error not exceeding 10.93%. Finally, the results evaluated showed that the modification with silicon nanomaterials gave very good results since the nanomaterials improved about 65% of the shell's mechanical properties and vibration characteristics

An Optimum Design of a Subsonic Aircraft Wing due to the Aerodynamic Loading

Aircraft designers are mainly interested in finding the level of pressure, stresses, and deformations of the parts of the aircraft wing. In many aviation accidents, the failure of the wing is the main cause of disasters, as it is considered the main surface that generates the necessary lift for the aircraft in addition to its other functions in controlling the transverse stability. In this work, a numerical study was performed to obtain the optimum wing structural design parameters for high strength and minimum weight for the L-39 A/C wing. The wing was modeled as a honeycomb with different thicknesses using the software SOLIDWORKS 2020. The pressure distribution was predicted using the FLUENT 2022 R1 package. Having obtained the aerodynamic pressure, the deformations and stresses were obtained using the ANSYS program. The results were compared with other researchers using other models, such as using ribs and stringers in the interior structure of the wing. The current results were found to be reliable and acceptable from the design point of view of the high stiffness-to-weight ratio