A Lumped Parameter Approach for Analysing a Metamaterial Beam Based Piezoelectric Energy Harvester Around Fundamental Resonance

2020 ◽  
Author(s):  
Guobiao Hu ◽  
Lihua Tang ◽  
Yaowen Yang
Keyword(s):  
Mode Shape ◽  
Fundamental Mode ◽  
Reaction Force ◽  
Element Model ◽  
Static Deflection ◽  
Lumped Parameter ◽  
Lumped Parameters ◽  
Mass Spring ◽  
Parameter Approach

Abstract This paper proposes a lumped parameter approach to simplify the modelling of a metamaterial based PEH to predict its energy harvesting performance around the fundamental resonance. The metamaterial based PEH consists of a host beam with a piezoelectric patch bonded at the clamped end. A series of local resonators are attached onto the host beam. In the first case study, the local resonators are modelled as mass-spring systems. By applying Rayleigh’s method and approximating the fundamental mode shape by the static deflection, the host beam is represented by a SDOF system. The equivalent lumped parameters are assumed to concentrate at the tip of the host beam and their explicit expressions are presented. Though the local resonators are identical, they have different influences on the host beam when being attached at different positions. To reflect the interaction degree (i.e., reacting force) between the local resonator and the host beam, a scaling factor that is a function of the attaching position is derived. On the other hand, due to the action of the local resonators, the fundamental mode shape of the host beam is actually changed. Based on the linear superposition principle, the static deflection approximated fundamental mode shape is corrected and the electromechanical coupling coefficient that is sensitive to the slope of the mode shape is updated to improve the accuracy. Based on the derived equivalent lumped parameters and correction factors, a multiple-degree-of-freedom (MDOF) model is constructed to predict the dynamic behavior of the metamaterial based PEH with mass-spring resonators. A corresponding finite element model is built to verify the developed MDOF model. In the second case study, the local resonators are modelled as practical parasitic beams. The parasitic beams are converted into equivalent lumped systems as well. However, the lumped parameters are the effective parameters at the beam tip. For the force interaction at the root of a parasitic beam, a factor is derived to correct the reaction force when a parasitic beam is represented by a SDOF mass-spring system. Using the reaction force correction factor, a MDOF model for the metamaterial based PEH with beam-like resonators is also established and verified by the finite element model.

Polar Orthotropic Inhomogeneous Circular Plates: Vibration Tailoring

2010 ◽  
Vol 77 (3) ◽  
Author(s):  
Demetris Pentaras ◽  
Isaac Elishakoff
Keyword(s):  
Eigenvalue Problem ◽  
Closed Form ◽  
Circular Plate ◽  
Mode Shape ◽  
Fundamental Mode ◽  
Inverse Eigenvalue Problem ◽  
Static Deflection ◽  
Circular Plates ◽  
Inverse Eigenvalue ◽  
Polar Orthotropic

Problem of matching a desired fundamental natural frequency is solved in the closed form for the polar-orthotropic inhomogeneous circular plate, which is clamped along its circumference. The vibration tailoring is performed by posing a semi-inverse eigenvalue problem. To do this, the fundamental mode shape is postulated. Namely, the analytical expression due to Lekhnitskii, and pertaining to the static deflection of the homogeneous circular plate is demanded to serve as an exact mode shape of the inhomogeneous plate. The analytical and numerical results are reported for several ratios of orthotropic coefficient.

A hybrid model to study the effect of tooth lead modifications on the dynamic behavior of double helical planetary gears

2019 ◽  
Vol 233 (21-22) ◽  
pp. 7224-7235
Author(s):  
Stéphane Portron ◽  
Philippe Velex ◽  
Vincent Abousleiman
Keyword(s):  
Dynamic Behavior ◽  
Hybrid Model ◽  
Load Distribution ◽  
Element Model ◽  
Ring Gear ◽  
Planetary Gears ◽  
Lumped Parameter ◽  
Lumped Parameter Models ◽  
Lumped Parameters ◽  
Planet Carrier

In this paper, a hybrid model is used to investigate the dynamic behavior of planetary gears. Sun-gear, planets, and ring-gear are modeled using lumped parameters elements, while planet carrier is integrated via a condensed finite element model. This approach intends to be more precise than the traditional lumped parameter models while keeping acceptable computational times. In some aeronautical applications, tooth lead modifications can be necessary to counterbalance the effect of planet carrier deflections on tooth load distribution. This study focuses on the influence of various lead modifications on the dynamic behavior of double helical planetary gears over a broad range of loads.

scholarly journals APPLICATION OF DOMAIN INTEGRATED DESIGN METHODOLOGY FOR BIO-INSPIRED DESIGN- A CASE STUDY OF SUTURE PIN DESIGN

2021 ◽  
Vol 1 ◽  
pp. 487-496
Author(s):  
Pavan Tejaswi Velivela ◽  
Nikita Letov ◽  
Yuan Liu ◽  
Yaoyao Fiona Zhao
Keyword(s):  
Cross Sections ◽  
Design Methodology ◽  
Reaction Force ◽  
Integrated Design ◽  
Total Deformation ◽  
Insertion Force ◽  
Force Reaction ◽  
The Moment ◽  
Work Done

AbstractThis paper investigates the design and development of bio-inspired suture pins that would reduce the insertion force and thereby reducing the pain in the patients. Inspired by kingfisher's beak and porcupine quills, the conceptual design of the suture pin is developed by using a unique ideation methodology that is proposed in this research. The methodology is named as Domain Integrated Design, which involves in classifying bio-inspired structures into various domains. There is little work done on such bio-inspired multifunctional aspect. In this research we have categorized the vast biological functionalities into domains namely, cellular structures, shapes, cross-sections, and surfaces. Multi-functional bio-inspired structures are designed by combining different domains. In this research, the hypothesis is verified by simulating the total deformation of tissue and the needle at the moment of puncture. The results show that the bio-inspired suture pin has a low deformation on the tissue at higher velocities at the puncture point and low deformation in its own structure when an axial force (reaction force) is applied to its tip. This makes the design stiff and thus require less force of insertion.

scholarly journals Evaluation of passive autocatalytic recombiners operation efficiency by means of the lumped parameter approach

Nukleonika ◽  
2015 ◽  
Vol 60 (2) ◽  
pp. 339-345 ◽  
Author(s):  
Tomasz Bury
Keyword(s):  
Hydrogen Generation ◽  
Cooling System ◽  
Component Mixture ◽  
Pressurized Water ◽  
Water Reactor ◽  
Safety Issues ◽  
Loss Of Coolant Accident ◽  
Lumped Parameter ◽  
Core Cooling ◽  
Parameter Approach

Abstract The problem of hydrogen behavior in containment buildings of nuclear reactors belongs to thermal-hydraulic area. Taking into account the size of systems under consideration and, first of all, safety issues, such type of analyses cannot be done by means of full-scale experiments. Therefore, mathematical modeling and numerical simulations are widely used for these purposes. A lumped parameter approach based code HEPCAL has been elaborated in the Institute of Thermal Technology of the Silesian University of Technology for simulations of pressurized water reactor containment transient response. The VVER-440/213 and European pressurised water reactor (EPR) reactors containments are the subjects of analysis within the framework of this paper. Simulations have been realized for the loss-of-coolant accident scenarios with emergency core cooling system failure. These scenarios include core overheating and hydrogen generation. Passive autocatalytic recombiners installed for removal of hydrogen has been taken into account. The operational efficiency of the hydrogen removal system has been evaluated by comparing with an actual hydrogen concentration and flammability limit. This limit has been determined for the three-component mixture of air, steam and hydrogen. Some problems related to the lumped parameter approach application have been also identified.

Integrity Assessment of Damaged Flexible Pipe Cross-Sections

2014 ◽  
Author(s):  
Guomin Ji ◽  
Bernt J. Leira ◽  
Svein Sævik ◽  
Frank Klæbo ◽  
Gunnar Axelsson ◽  
...  
Keyword(s):  
Cross Sections ◽  
Three Dimensional ◽  
Element Model ◽  
Computer Code ◽  
Flexible Pipe ◽  
Dynamic Stresses ◽  
Integrity Assessment ◽  
Residual Capacity ◽  
Nonlinear Finite Element Model

This paper presents results from a case study performed to evaluate the residual capacity of a 6″ flexible pipe when exposed to corrosion damages in the tensile armour. A three-dimensional nonlinear finite element model was developed using the computer code MARC to evaluate the increase in mean and dynamic stresses for a given number of damaged inner tensile armor wires. The study also includes the effect of these damages with respect to the associated stresses in the pressure spiral. Furthermore, the implications of a sequence of wire failures with respect to the accumulated time until cross-section failure in a probabilistic sense are addressed.

Numerical Study for Global Detection of Cracks Embedded in Beams

1999 ◽  
Author(s):  
S. A. Lipsey ◽  
Y. W. Kwon
Keyword(s):  
Finite Element ◽  
Dynamic Analysis ◽  
Natural Frequency ◽  
Mode Shape ◽  
Numerical Study ◽  
Element Model ◽  
Mode Shapes ◽  
Linear Effect ◽  
Modes Of Vibration ◽  
Damage Simulation

Abstract Damage reduces the flexural stiffness of a structure, thereby altering its dynamic response, specifically the natural frequency, damping values, and the mode shapes associated with each natural frequency. Considerable effort has been put into obtaining a correlation between the changes in these parameters and the location and amount of the damage in beam structures. Most numerical research employed elements with reduced beam dimensions or material properties such as modulus of elasticity to simulate damage in the beam. This approach to damage simulation neglects the non-linear effect that a crack has on the different modes of vibration and their corresponding natural frequencies. In this paper, finite element modeling techniques are utilized to directly represent an embedded crack. The results of the dynamic analysis are then compared to the results of the dynamic analysis of the reduced modulus finite element model. Different modal parameters including both mode shape displacement and mode shape curvature are investigated to determine the most sensitive indicator of damage and its location.

Use of DNVGL-RP-C203 for Determining the Fatigue Capacity of Connectors

2021 ◽  
Author(s):  
Anthony Muff ◽  
Anders Wormsen ◽  
Torfinn Hørte ◽  
Arne Fjeldstad ◽  
Per Osen ◽  
...  
Keyword(s):  
Finite Element ◽  
Fatigue Testing ◽  
Experimental Testing ◽  
High Strength ◽  
Element Model ◽  
Fatigue Analysis ◽  
Full Scale ◽  
The Finite Element Model

Abstract Guidance for determining a S-N based fatigue capacity (safe life design) for preloaded connectors is included in Section 5.4 of the 2019 edition of DNVGL-RP-C203 (C203-2019). This section includes guidance on the finite element model representation, finite element based fatigue analysis and determination of the connector design fatigue capacity by use of one of the following methods: Method 1 by FEA based fatigue analysis, Method 2 by FEA based fatigue analysis and experimental testing and Method 3 by full-scale connector fatigue testing. The FEA based fatigue analysis makes use of Appendix D.2 in C203-2019 (“S-N curves for high strength steel applications for subsea”). Practical use of Section 5.4 is illustrated with a case study of a fatigue tested wellhead profile connector segment test. Further developments of Section 5.4 of C203-2019 are proposed. This included acceptance criteria for use of a segment test to validate the FEA based fatigue analysis of a full-scale preloaded connector.

scholarly journals A novel strain sensor using a microchannel embedded in PDMS

2018 ◽  
Vol 4 (2) ◽  
pp. 1 ◽  
Author(s):  
Angelica Campigotto ◽  
Stephane Leahy ◽  
Ayan Choudhury ◽  
Guowei Zhao ◽  
Yongjun Lai
Keyword(s):  
Finite Element ◽  
Rotation Angle ◽  
Strain Sensor ◽  
Element Model ◽  
Strain Sensors ◽  
Gauge Factor ◽  
Sectional Area ◽  
Cross Sectional ◽  
Higher Sensitivity

A novel, inexpensive, and easy-to-use strain sensor using polydimethylsiloxane (PDMS)  was developed. The sensor consists of a microchannel that is partially filled with a coloured liquid and embedded in a piece of PDMS. A finite element model was developed to optimize the geometry of the microchannel to achieve higher sensitivity. The highest gauge factor that was measured experimentally was 41. The gauge factor was affected by the microchannel’s square cross-sectional area, the number of basic units in the microchannel, and the inlet and outlet configuration. As a case study, the developed strain sensors were used to measure the rotation angle of the wrist and finger joints.

scholarly journals Thermo-mechanical analysis of linear welding stage in friction stir welding - influence of welding parameters

2021 ◽  
pp. 186-186
Author(s):  
Darko Veljic ◽  
Marko Rakin ◽  
Aleksandar Sedmak ◽  
Nenad Radovic ◽  
Bojan Medjo ◽  
...  
Keyword(s):  
Friction Stir Welding ◽  
Heat Generation ◽  
Welding Speed ◽  
Reaction Force ◽  
Material Model ◽  
Element Model ◽  
Welding Parameters ◽  
Al Alloy ◽  
Friction Stir ◽  
Fsw Parameters

The influence of friction stir welding (FSW) parameters on thermo-mechanical behaviour of the material during welding is analysed. An aluminium alloy is considered (Al 2024 T351), and different rotating speed and welding speed are applied. Finite element model consists of the plate (Al alloy), backing plate and welding tool, and it is formed and solved in software package Simulia Abaqus. The influence of the welding conditions on material behaviour is taken into account by application of the Johnson-Cook material model. The rotation of the tool affects the results: if increased, it contributes to an increase of friction-generated heat intensity. The other component of the generated heat, the plastic deformation of the material, is negligibly changed. When the welding speed is increased, the intensity of friction-generated heat decreases, while the heat generation due to plastic deforming increases. Combined, these two effects cause small change of the total heat generation. For the same welded joint length, the plate welded by lower speed will be heated more intensively. The changes of the heat generation influence both the temperature field and reaction force, which are also considered.

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