Modelling and Experimental Validation of a Novel Piezohydraulic Servovalve

2011 ◽  
Author(s):  
Dhinesh K. Sangiah ◽  
Andrew R. Plummer ◽  
Christopher R. Bowen ◽  
Paul Guerrier
Keyword(s):  
Electrical Power ◽  
Test Results ◽  
Bernoulli Beam ◽  
Element Analysis ◽  
First Order ◽  
Beam Analysis ◽  
Design Tradeoffs ◽  
Fast Flow ◽  
Euler Bernoulli Beam ◽  
Good Agreement

Servovalves are compact, accurate, fast flow modulating valves. However, cost reduction pressures exist, not least due to the electomagnetically actuated pilot stage. This paper describes a servovalve with a jet deflector pilot stage actuated by a multilayer piezoelectric bimorph. The electrical power and voltage requirements are relatively low (+/−30V), and mechanical spool feedback is used as opposed to the more complex electrical feedback alternative. A mathematical model of the valve is presented, which is used to simulate its performance. Finite element analysis is used to model the bimorph actuator and the feedback wire assembly to verify an Euler-Bernoulli beam analysis. A Moog 26 Series servovalve is used as a basis for the prototype. Experimental test results are in good agreement with the simulation results. The high order nonlinear model is also approximated by a first order transfer function to identify the parameters that dictate the main design tradeoffs.

Experimental and theoretical study of sandwich composites with Z-pins under quasi-static compression loading

2021 ◽  
pp. 136943322110073
Author(s):  
Erdem Selver ◽  
Gaye Kaya ◽  
Hussein Dalfi
Keyword(s):  
Vinyl Ester ◽  
Failure Modes ◽  
Critical Role ◽  
Sandwich Composites ◽  
Test Results ◽  
Compressive Properties ◽  
Element Analysis ◽  
Static Compression ◽  
Quasi Static Compression ◽  
Good Agreement

This study aims to enhance the compressive properties of sandwich composites containing extruded polystyrene (XPS) foam core and glass or carbon face materials by using carbon/vinyl ester and glass/vinyl ester composite Z-pins. The composite pins were inserted into foam cores at two different densities (15 and 30 mm). Compression test results showed that compressive strength, modulus and loads of the sandwich composites significantly increased after using composite Z-pins. Sandwich composites with 15 mm pin densities exhibited higher compressive properties than that of 30 mm pin densities. The pin type played a critical role whilst carbon pin reinforced sandwich composites had higher compressive properties compared to glass pin reinforced sandwich composites. Finite element analysis (FE) using Abaqus software has been established in this study to verify the experimental results. Experimental and numerical results based on the capabilities of the sandwich composites to capture the mechanical behaviour and the damage failure modes were conducted and showed a good agreement between them.

Electrothermally Tunable Bridge Resonator

2016 ◽  
Author(s):  
Amal Z. Hajjaj ◽  
Nouha Alcheikh ◽  
Abdallah Ramini ◽  
Md Abdullah Al Hafiz ◽  
Mohammad I. Younis
Keyword(s):  
Fundamental Frequency ◽  
Beam Theory ◽  
Element Model ◽  
Bernoulli Beam ◽  
Electrothermal Actuation ◽  
Wide Range ◽  
Simulation Results ◽  
Dc Current ◽  
Euler Bernoulli Beam ◽  
Good Agreement

This paper demonstrates experimentally, theoretically, and numerically a wide-range tunability of an in-plane clamped-clamped microbeam, bridge, and resonator compressed by a force due to electrothermal actuation. We demonstrate that a single resonator can be operated at a wide range of frequencies. The microbeam is actuated electrothermally, by passing a DC current through it. We show that when increasing the electrothermal voltage, the compressive stress inside the microbeam increases, which leads eventually to its buckling. Before buckling, the fundamental frequency decreases until it drops to very low values, almost to zero. After buckling, the fundamental frequency increases, which is shown to be as high as twice the original resonance frequency. Analytical results based on the Galerkin discretization of the Euler Bernoulli beam theory are generated and compared to the experimental data and to simulation results of a multi-physics finite-element model. A good agreement is found among all the results.

Finite Element Analysis of Dry Shrinkage of Fiber Cement Mortar

2014 ◽  
Vol 590 ◽  
pp. 312-315
Author(s):  
Wei Hong Xuan ◽  
Pan Xiu Wang ◽  
Yu Zhi Chen ◽  
Xiao Hong Chen
Keyword(s):  
Fracture Toughness ◽  
Cement Mortar ◽  
Polypropylene Fiber ◽  
Polypropylene Fibers ◽  
Test Results ◽  
Ansys Software ◽  
Element Analysis ◽  
Cement Based Materials ◽  
Dry Shrinkage ◽  
Good Agreement

The dry shrinkage deformation of polypropylene fiber mortar was analyzed by ANSYS software and compared with experiment value in this paper. The error of the calculated and experimental results in the 14 days and 28 days are 7.8% and 10.5%. It can be found that the calculated results are in good agreement with test results. The results indicate that the dry shrinkage value of polypropylene fiber mortar is lower than ordinary mortar. Adding polypropylene fibers can inhibit the process of cracking and improve the fracture toughness of cement-based materials.

Vibration Analysis of Multi-Cracked Beam Traversed by Moving Masses Using Discrete Element Technique

2013 ◽  
Vol 376 ◽  
pp. 220-223
Author(s):  
Reza Alebrahim ◽  
Nik Abdullah Nik Mohamed ◽  
Sallehuddin Mohamed Haris ◽  
Salvinder Singh Karam Singh
Keyword(s):  
Vibration Analysis ◽  
Beam Theory ◽  
Discrete Element ◽  
Maximum Deflection ◽  
Bernoulli Beam ◽  
Cracked Beam ◽  
Time To Build ◽  
Element Technique ◽  
Euler Bernoulli Beam ◽  
Good Agreement

The vibration analysis of a multi-cracked beam using discrete element technique (DET) was investigated in this study. Undamped simply supported beam was traversed by moving mass with constant speed and Euler Bernoulli beam theory was considered. Cracks are located in different positions and maximum deflection of mid-span was derived and compared. The results showed that increasing numbers of cracks in the beam causes more deflection while maximum deflection of beam takes longer time to build up. The results were validated by solving the equations generated using finite element method (FEM) and their comparison with already established results from previous similar studies (literatures) showed good agreement.

Experimental Research and Finite Element Analysis of BFRP Flexural Strengthening Efficiencies of Pre-Damaged Concrete Beams

2013 ◽  
Vol 834-836 ◽  
pp. 720-725 ◽  
Author(s):  
Hai Liang Wang ◽  
Wei Chang ◽  
Xin Lei Yang
Keyword(s):  
Numerical Simulation ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Test Results ◽  
Element Analysis ◽  
Flexural Strengthening ◽  
Flexural Resistance ◽  
Good Agreement

Six reinforced concrete beams, including 4 beams strengthened with BFRP sheets at different layer of BFRP sheets and 2 control beams, are tested to investigate the effect of layer of BFRP sheets on the ultimate flexural resistance and load-deflection response of the pre-damaged concrete beams strengthened with BFRP sheets. Results show that the flexural resistance of pre-damaged concrete beams increases along with the BFRP sheets layer increasing,but the flexural resistance enhances the degree not to assume the linear relations to the enforcement layer.Numerical simulation of the pre-damaged concrete beams strengthened with BFRP sheets is conducted by ANSYS, and the results of numerical simulation are compared with those of the test results. It turns out that the results of numerical simulation are in good agreement with the test results.

scholarly journals Euler-Bernoulli Beam Theory: First-Order Analysis, Second-Order Analysis, Stability, and Vibration Analysis Using the Finite Difference Method

2021 ◽  
Author(s):  
Valentin Fogang
Keyword(s):  
Finite Difference Method ◽  
Differential Equations ◽  
Vibration Analysis ◽  
Beam Theory ◽  
Second Order ◽  
Bernoulli Beam ◽  
Order Analysis ◽  
First Order ◽  
The Finite Difference Method ◽  
Euler Bernoulli Beam

This paper presents an approach to the Euler-Bernoulli beam theory (EBBT) using the finite difference method (FDM). The EBBT covers the case of small deflections, and shear deformations are not considered. The FDM is an approximate method for solving problems described with differential equations (or partial differential equations). The FDM does not involve solving differential equations; equations are formulated with values at selected points of the structure. The model developed in this paper consists of formulating partial differential equations with finite differences and introducing new points (additional points or imaginary points) at boundaries and positions of discontinuity (concentrated loads or moments, supports, hinges, springs, brutal change of stiffness, etc.). The introduction of additional points permits us to satisfy boundary conditions and continuity conditions. First-order analysis, second-order analysis, and vibration analysis of structures were conducted with this model. Efforts, displacements, stiffness matrices, buckling loads, and vibration frequencies were determined. Tapered beams were analyzed (e.g., element stiffness matrix, second-order analysis). Finally, a direct time integration method (DTIM) was presented. The FDM-based DTIM enabled the analysis of forced vibration of structures, the damping being considered. The efforts and displacements could be determined at any time.

scholarly journals Natural Frequencies and Mode Shapes of Statically Deformed Inclined Risers

2016 ◽  
Author(s):  
Feras K. Alfosail ◽  
Ali H. Nayfeh ◽  
Mohammad I. Younis
Keyword(s):  
Natural Frequencies ◽  
Equilibrium Configuration ◽  
Mode Shapes ◽  
Bernoulli Beam ◽  
Galerkin Approach ◽  
Inclination Angles ◽  
Linear Vibrations ◽  
Euler Bernoulli Beam ◽  
Beam Mode ◽  
Good Agreement

In this work, we investigate numerically the linear vibrations of inclined risers using the Galerkin approach. The riser is modeled as an Euler-Bernoulli beam accounting for the nonlinear mid-plane stretching and self-weight. After solving for the initial deflection of the riser due to self-weight, a Galerkin expansion of fifteen axially loaded beam mode shapes are used to solve the eigenvalue problem of the riser around the static equilibrium configuration. This yields the riser natural frequencies and exact mode shapes for various values of inclination angles and applied tension. The obtained results are validated against a boundary-layer analytical solution and are found in good agreement. This constructs a basis to study the nonlinear forced vibrations of inclined risers.

Finite Element Analysis of Hybrid Fiber Reinforced HPC Deep Beams under Shear Load

2013 ◽  
Vol 419 ◽  
pp. 889-894
Author(s):  
Sheng Bing Liu ◽  
Li Hua Xu
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Polypropylene Fiber ◽  
Shear Capacity ◽  
Test Results ◽  
Fiber Reinforced ◽  
Hybrid Fiber ◽  
Deep Beams ◽  
Element Analysis ◽  
Good Agreement

18 different groups of hybrid fiber (steel fiber and polypropylene fiber) reinforced HPC deep beams and 2 groups of HPC deep beams without fiber were made. The shear tests under the static load and the numerical simulation by ABAQUS were conducted. Good agreement are found between test results and simulation results.The results of finite element analysis indicate that with the increment of reinforcement ratio, the shear capacity of hybrid fiber reinforced HPC deep beams increases, but quite limited. The variation of shear capacity of hybrid fiber reinforced HPC deep beams is not obvious as the shear-span ratio changes (when ) . The increment of span-depth ratio can improve the shear capacity of hybrid fiber reinforced HPC deep beams, but only with small amplitude. All these regularities are similar to those of ordinary reinforced concrete deep beams.

Inelastic Behavior of Threaded Piping Connections: Reconciliation of Experimental and Analytic Results

2011 ◽  
Author(s):  
Yonghee Ryu ◽  
Anahid Behrouzi ◽  
Tsega Melesse ◽  
Vernon C. Matzen
Keyword(s):  
Inelastic Behavior ◽  
Test Results ◽  
Element Analysis ◽  
Shell Elements ◽  
Rotational Spring ◽  
Beam Elements ◽  
Piping Systems ◽  
Threaded Joints ◽  
Rigid Connection ◽  
Euler Bernoulli Beam

Modeling the behavior of piping systems with threaded joints is difficult because the joints do not act as rigid connections. At one level of approximation the connection can be modeled as a semi-rigid connection using a rotational spring. This study modeled a straight pipe using either Euler-Bernoulli beam elements [4] or Finite Element Analysis (FEA) shell elements and a support condition using the rotational spring. Laboratory tests were conducted on 1 in. diameter specimens of black iron Schedule 40 pipe in a cantilever configuration. The specimen was loaded monotonically into the inelastic region. A Ramberg-Osgood model [5] was used to represent the rotational spring and the correlation between test results and analytical predictions was quite good.

Large Deformation Geometric Nonlinear Beam Element Based on U.L. Format

2012 ◽  
Vol 446-449 ◽  
pp. 3596-3603
Author(s):  
Yong Jun Xia ◽  
Qian Miao
Keyword(s):  
Displacement Field ◽  
Strain Tensor ◽  
Quadratic Function ◽  
Beam Element ◽  
Interpolation Polynomial ◽  
Bernoulli Beam ◽  
Displacement Fields ◽  
First Order ◽  
Geometric Nonlinear ◽  
Euler Bernoulli Beam

Based on the geometric deformation of the Euler-Bernoulli beam element, the geometric nonlinear Euler-Bernoulli beam element based on U.L. formulation is derived. The element’s transverse first-order displacement field is constructed using the cubic Hermite interpolation polynomial, and the first-order Lagrange interpolation polynomial is used for the axial displacement field. Then the additional displacements induced from the rotation of the elemental are included into the transverse and longitudinal displacement fields, so those displacement fields are expressed as the quadratic function of nodal displacement. Afterwards the nonlinear finite element formulas of Euler-Bernoulli beam element under the form of U.L. formulation are derived using Cauchy strain tensor and the principle of virtual displacements. The total equilibrium equation and tangent stiffness for large displacement geometric nonlinear analysis of frame are obtained in the total coordinate system. The correctness of this element is proved by typical example.

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