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The project involves the simulation of an organic/polymer-based Tribo-Electric Nano Generator (TENG), to generate electricity from the vast mechanical energy wasted in the form of friction from human footfalls. The energy conversion in the device is achieved by the triboelectric effect, which is the electrostatic effect where, the interaction between 2 materials that vary in degree of polarity of triboelectricity, generates electricity. The complexity in process and need of multiple fabrication technologies, wide range of characterization, cost and time involved in actual experimental process in working with new materials or with multi material systems and the possibility of understanding is invariably reduced using the process of simulation. The structures simulated using COMSOL Multiphysics® 5.3, consists of PDMS (Polydimethylsiloxane), gold, and gold nano-particles on PMMA (Polymethylmethacrylate), with gold replaced by aluminum and with copper for experimentation, with PDMS polymer thickness optimized to 10 µm, generating maximum voltage in the order of 103 Volts. The expected power generated by this vertical contact mode generator with gold-coated electrodes is 15mW.

Painovoimaisen ilmanvaihdon käsitettä purkautumiskerroin selostetaan erityisesti kontrollitilavuustarkastelujen avulla mekaanisen energian taseen periaatetta soveltamalla. Yksinkertainen esimerkkitapaus esitetään. Alan terminologiaa kommentoidaan. Artikkeli on aiheeltaan opetuksellinen.

The finite-volume theory is an equilibrium-based approach characterized by the equilibrium equations' local satisfaction and the imposition of continuity conditions in a surface-averaged sense through the subvolume interfaces. Previous investigations include stress and displacement fields convergence and computational cost, showing the approach's efficiency, especially in heterogeneous materials and structures. However, those investigations did not include an energy analysis, which is especially important in compliance minimization problems. As the finite element method, energy-based approaches impose energy balance, which guarantees a monotonic energy convergence. This contribution addresses a numerical investigation of the main mechanical energy aspects involving the generalized finite-volume theory for continuum elastic structures in quasi-static analyses. The obtained results are verified with analytical and finite element-based analyses, showing the monotonic energy convergence for the three versions of the finite-volume theory and the energy balance's satisfaction for the higher-order versions when a sufficiently refined mesh is employed.

In this letter, we introduce a novel control strategy called Virtual Energy Regulator (VER) for lower limb rehabilitation exoskeletons. Unlike the conventional trajectory tracking controllers, VER, which is a time-independent controller, does not control the exoskeleton joints over a reference trajectory. Instead, it imposes a constraint to the state-space and consequently creates a limit cycle for each joint. The time-independent property of VER can resolve the human-exoskeleton coordination problem. The analytical perspectives of VER are studied in detail where we present the limit cycle existence conditions, considerations for the definition of the desired limit cycles, convergence proof, and limit-cycles synchronization. Finally, to support the presented mathematics, we apply the designed VER on Indego exoskeleton (without human) to perform a limit-cycle behavior similar to walking. The experimental and simulation results show that VER generates stable and synchronized limit-cycles at the joints. Our experimental and simulation results support our analytical findings and demonstrate the efficacy of VER for lower limb exoskeletons.

The bi-articular muscle–tendon complex (MTC) in an animal's leg allows a transfer of mechanical power between adjacent joints and exertion of a large force at the toes. It is capable of storing and releasing elastic energy efficiently during motions. In our previous studies, we proposed mechanisms of the bi-articular MTC for achieving extension of the upper and lower parts of the leg and experimentally demonstrated that each mechanism allows the higher jumping motion of a legged robot. In this study, we developed a bio-inspired legged robot by integrating the upper and lower leg bi-articular MTCs and investigated the effect of their cooperative utilization on the improvement of the vertical jumping ability. A jumping motion trajectory was generated through optimization to maximize the jumping ability based on a dynamic model of the bio-inspired legged robot with these bi-articular MTCs. The simulation results of the models with and without bi-articular MTCs were compared. Finally, through jumping experiments performed by implementing the generated motion trajectory, it was confirmed that the jumping ability was improved by the cooperative utilization of those bi-articular MTCs.

Centrifugal pump is a kind of energy conversion machine for fluid delivering. It transfers the mechanical energy of impeller to the potential and kinetic energy of fluid. As a key factor in influencing the energy conversion performance of centrifugal pump, blade profile design is crucial. Traditional design concepts have ideal assumptions. To have a better design guidance, machine-learning based on neural network is used in this study. A typical centrifugal pump with simplified blade profile is numerically studied with experimental validation for a better discussion. Statistical results show that, for the high dimensional nonlinear relationship between blade angle and performance of centrifugal pump, neural network can adapt to this complex correlation better. The blade installation angle at leading-edge ( βLE′) and trailing-edge ( βTE′) and the wrap angle (Δ θ′) has significant correlation with the performance including pump head H, pump efficiency η, impeller head Himp, impeller efficiency ηimpand volute loss Δ Hvol. The influence level of blade angle follows the high-to-low order of Δ θ′, βLE′ and βTE′. Determination of blade profile can be done for improving the energy conversion efficiency. Optimal blade profiles have higher βLE′ and Δ θ′ with better flow-control ability. Compared with the blade parameters of the initial pump, the blade profile with the best centrifugal pump efficiency is the best βLE′ increased by 1.926°, Δ θ′ increased by 9.858°, Optimization of impeller efficiency βLE′ increased by 1.855°, Δ θ′ increased by 9.421°. Computational fluid dynamics indicate the elimination of vortex in impeller after optimal selection. Then, βTE′ and Δ θ′ are found influential in aggravating the circumferential flow component in this special circular-volute with generating higher loss. βTE′ has a positive correlation with impeller head which suits traditional theory. In general, the machine-learning using neural network is effective in determining blade profiles for enhancing the performance of centrifugal pump.

The main purpose of the motor mode is to keep the turbine in hot standby (with the boiler off) without generating electricity to the grid. To do this, the generator is switched to the engine mode, which rotates the turbine rotor, and the cooling of the flow path is performed by supplying one or two intermediate steam extractions from the extractions of the neighboring turbine. The first stages of the high-pressure cylinder run on steam from the front seals. The noted specificity of the purpose and operating conditions of the turbine in low-steam modes imposes additional requirements on the mathematical model. When developing models of a turbine stage in a motor mode, the physical media included in the object were taken into account: the steam of the flow path passing through the nozzle and working discs, participating in the conversion of its thermodynamic and kinetic energy into mechanical energy of the rotor rotation; vapor leakage into the space between the discs; steam leakage through the rotor-guide vane seal; metal of rotating devices (working disks and turbine rotor); and metal of the stator and exhaust pipes. Multipoint models are obtained with lumped parameters distributed along the length of the flow channel with values that vary depending on the ordinal number of the stage. The main part of the step models are eight ordinary differential equations or partial differential equations of physical media. The developed models are necessary for computer modeling and investigating the temperature distribution of the turbine flow path. Based on the research results, it is proposed to create a real automatic control system that ensures the implementation of restrictions on metal heating and the generation of added power.

The objective of this study was to evaluate the performance of 24 basic hydrodynamic mechanical power-split (HMPS) transmission designs effectively based on their torque multiplication capacities (TMCs) and efficiencies. Firstly, four schemes were preliminarily selected. Secondly, the matching between the four schemes and a reference wheel loader was considered, and an expression for the TMC was developed based on the traditional transmission and a second reference transmission. Thirdly, two performance metrics in terms of the TMC and efficiency – the average torque multiplication capacity (ATMC) and average efficiency – were defined to eliminate the couplings of four transmission parameters with the vehicle speed and speed ratio. Finally, the performances of the two best schemes and traditional hydrodynamic mechanical (HM) transmission were carefully compared. The results show that a transmission with power recirculation cannot present energy savings potential regardless of the ATMC, whereas a transmission with a power split can achieve an ATMC of 0.255, an average efficiency increment of 0.0143 in the short loading cycle, and a miniscule efficiency increment in the long loading cycle compared with the HM transmission.

Recently, researchers have produced a triboelectric nanogenerators (TENGs) technology that can harvest mechanical energy. However, the expensive fabrication materials still hinder its widespread. T...

Power delivery efficiency tackles technical assessment of power portions which are applied or wasted by an off-road vehicle. In this study, contributory influences of major causative factors of drive mode (rear wheel drive and front wheel-assisted drive) and drive speed (2, 4, and 6 km/h) on the power delivery efficiency of a front wheel assist tractor in tillage works were analyzed with consideration of constant drivetrain efficiency. Values of the power delivery efficiency were analyzed by analysis of variance procedure in confidence bound of 0.99. The experimental design for the procedure was randomly arranged in triplicate for each combination of drive modes and speeds. It corroborated that percentage of increasing influence of drive mode (+ 13.21%) on the power delivery efficiency (54.26–72.78%) was approximately equal to that of linear decreasing influence of drive speed (− 14.88%). This happened while driving lead of tractor front wheels in front wheel-assisted drive mode was in permissible range of 2.57–4.52%. Meanwhile, portion of the slip efficiency in the power delivery efficiency was notably less (averagely 17.95%) than that of the motion efficiency for each tested condition. This implied that a remarkable portion of mechanical power produced by tractor engine in tillage works was wasted through slip (averagely 9.48 kW) followed by rolling resistance force (averagely 2.45 kW) of tractor wheels. This form of wasted power is undesirably used for recoverable (elastic) and irrecoverable (plastic) deformation of tires and soil, respectively. As drive speed increased, the slip efficiency decreased and thereby this wasted power increased. To compensate the negative influence of drive speed on the power delivery efficiency in tillage works, employment of front wheel-assisted drive mode of the tractor can be considered as practical solution in permissible range of the driving lead.

Concrete with smart and functional properties (e.g., self-sensing, self-healing, and energy harvesting) represents a transformative direction in the field of construction materials. Energy-harvesting concrete has the capability to store or convert the ambient energy (e.g., light, thermal, and mechanical energy) for feasible uses, alleviating global energy and pollution problems as well as reducing carbon footprint. The employment of energy-harvesting concrete can endow infrastructures (e.g., buildings, railways, and highways) with energy self-sufficiency, effectively promoting sustainable infrastructure development. This paper provides a systematic overview on the principles, fabrication, properties, and applications of energy-harvesting concrete (including light-emitting, thermal-storing, thermoelectric, pyroelectric, and piezoelectric concretes). The paper concludes with an outline of some future challenges and opportunities in the application of energy-harvesting concrete in sustainable infrastructures.

The evolution of the attitude angle and the mechanical energy exchange between the bus system and the solar sail via the connecting wires are the main manifestations of the coupling dynamic effects on the orbit evolution, the attitude adjusting and the flexible vibration of the tethered satellite system. To investigate attitude evolution of the tethered system and the mechanical energy transfer/loss characteristics between the bus system and the solar sail via the connecting wires, a structure-preserving method is developed in this paper. Simplifying the tethered satellite system as a composite structure consisting of a particle and a flexible thin panel connected by four special springs, the dynamic model is deduced via the Hamiltonian variational principle firstly. Then, a structure-preserving approach that connects the symplectic Runge–Kutta method and the multi-symplectic method is developed. The excellent structure-preserving property of the numerical scheme constructed is presented to illustrate the credibility of the numerical results obtained by the constructed structure-preserving approach. From the numerical results on the mechanical energy transfer/loss in the composite structure, it can be found that the mechanical energy transfer tendency in the tethered system is dependent of the initial attitude angle of the system while the total mechanical energy loss of the system is almost independent of the initial attitude angle. In addition, the special stiffness range of the spring is found in the attitude angle evolution of the system, which provides a structural parameter design window for the connecting wires, that is, the duration needed to arrive the stable attitude is short when the stiffness of the wire is designed in this special range. The evolution of the attitude angle and the mechanical energy exchange between the bus system and the solar sail via the connecting wires are the main manifestations of the coupling dynamic effects on the orbit evolution, the attitude adjusting and the flexible vibration of the tethered satellite system. To investigate attitude evolution of the tethered system and the mechanical energy transfer/loss characteristics between the bus system and the solar sail via the connecting wires, a structure-preserving method is developed in this paper. Simplifying the tethered satellite system as a composite structure consisting of a particle and a flexible thin panel connected by four special springs, the dynamic model is deduced via the Hamiltonian variational principle firstly. Then, a structure-preserving approach that connects the symplectic Runge-Kutta method and the multi-symplectic method is developed. The excellent structure-preserving property of the numerical scheme constructed is presented to illustrate the credibility of the numerical results obtained by the constructed structure-preserving approach. From the numerical results on the mechanical energy transfer/loss in the composite structure, it can be found that the mechanical energy transfer tendency in the tethered system is dependent of the initial attitude angle of the system while the total mechanical energy loss of the system is almost independent of the initial attitude angle. In addition, the special stiffness range of the spring is found in the attitude angle evolution of the system, which provides a structural parameter design window for the connecting wires, that is, the duration needed to arrive the stable attitude is short when the stiffness of the wire is designed in this special range.

Wind turbines are the devices used to harness wind energy. The turbine blades are one of the components which directly confront the wind and convert it into mechanical energy. Various material composites are used in the turbine industries to manufacture wind turbine blades but it is hard to select the best material composite along with the choices. In this study, an MCDM technique named Measurement of Alternatives and Ranking according to Compromise Solution (MARCOS) method is applied to select the best material composite among the set of materials for manufacturing of the blades. The weights of the criteria are determined by the Best Worst (BWM) method. Around 9 criteria such as the ultimate tensile strength, stiffness, cost of the materials, panel stability parameter of the material etc. are used to rank the best alternative among the blade materials. The carbon fibre reinforced plastic is seen to be the best material among the other materials composite by applying the MARCOS method.

Flywheel energy storage systems (FESS) are devices that are used in short duration grid-scale energy storage applications such as frequency regulation and fault protection. The energy storage component of the FESS is a flywheel rotor, which can store mechanical energy as the inertia of a rotating disk. This article explores the interdependence of key rotor design parameters, i.e., shape, operating speed, rotor radius, standby losses, and choice of material, and their influence on the energy storage characteristics of the FESS. Two commercially manufactured metal flywheels with distinct energy storage characteristics are used as case studies to examine the potential benefit of using shape optimization in combination with operating speed, size, and material selection for rotor design. A sequential hybrid optimization strategy that combines a global genetic algorithm with a gradient-based local method is used to solve the rotor shape optimization problem. The choice of an optimal combination of operating speed and rotor radius, together with shape optimization, is demonstrated to provide 21–46% improvements in the energy capacity of two existing commercial FESS designs. Results show that self discharge losses in the rotor can be reduced by designing optimally shaped rotors with large radii operating at low speeds. It is advantageous, on an “energy-per-cost of material” basis, to use steel as the rotor material for optimally shaped flywheels with large radii operated at low speeds. Conversely, aluminium is a better choice of material for flywheels with smaller radii operated at high speeds.

The increasing interest in harvesting mechanical energy from day-to-day activities is gaining huge interest among researchers. We have fabricated a triboelectric nanogenerator (TENG) made of aluminum and PDMS film acting as positive and negative triboelectric layers. The layers are arranged in an arc-shaped structure with an air gap of 1 cm between the layers of the device. The PDMS layer is made by blending the polymer solution with the hardener in an appropriate ratio and dried to make the transparent and flexible polymer film. The device shows a maximum electrical response of 110 V and 260 nA voltage and current with the power density of 2.9 mW/m2 at 100 MΩ load resistance. Further, the device has been used for lighting green LEDs and charging commercial capacitors. An Arduino board was connected with LED and buzzer, which was triggered by the TENG device. This shows that with the proper usage of electronic components TENG can be used for self-powered sensors and with IoT applications.

In the past decades, many mechanical metamaterials with uncommon static properties have been reported. On the other hand, mechanical metamaterials possessing extraordinary dynamic performance, also referred to as acoustic/elastic metamaterials, have gained more and more attractions. Examples include acoustic cloaking metamaterials that can generate an invisible region for acoustic waves, zero-stiffness metamaterials that can isolate vibrating mechanical energy, origami-based metamaterials that can realize the directional transmission of elastic waves and so on. To better understand the mechanisms adopted in dynamic mechanical metamaterials and present a general view about the existing works, we have reviewed some representative works and categorized them based on the ways of how these mechanical metamaterials manipulate the interactions between matters and mechanical energy. To distinguish the different categories of the dynamic mechanical metamaterials, we use a pair of binary numbers to measure the changing states of the magnitude and direction of the energy flow, respectively. A summary of some research works with associated reference numbers is presented in this paper with emphasis on the operating frequency, working bandwidth, and characteristic size of the element.

The consumption of low-power electronic devices has increased rapidly, where almost all applications use power electronic devices. Due to the increase in portable electronic devices’ energy consumption, the piezoelectric material is proposed as one of the alternatives of the significant alternative energy harvesters. This study aims to create a prototype of “Smart Shoes” that can generate electricity using three different designs embedded by piezoelectric materials: ceramic, polymer, and a combination of both piezoelectric materials. The basic principle for smart shoes’ prototype is based on the pressure produced from piezoelectric material converted from mechanical energy into electrical energy. The piezoelectric material was placed into the shoes’ sole, and the energy produced due to the pressure from walking, jogging, and jumping was measured. The energy generated was stored in a capacitor as piezoelectric material produced a small scale of energy harvesting. The highest energy generated was produced by ceramic piezoelectric material under jumping activity, which was 1.804 mJ. Polymer piezoelectric material produced very minimal energy, which was 55.618 mJ. The combination of both piezoelectric materials produced energy, which was 1.805 mJ from jumping activity.

In order to harvest effectively the mechanical energy produced in the process of vessel rolling, an energy harvest unit installed on the vessel is designed to utilize the mechanical energy. Firstly, the structure of the unit is proposed, and the relevant mathematical model is established. The solution of the mathematical model is given by Newmark- β method. Then, the influence of vessel rolling period and angle on the unit’s power and related parameters of the block is studied by MATLAB simulation. The results show that when the vessel is rolling, the energy harvest unit has a considerable power generation effect, the rolling period and angle of the vessel have a great impact on the power of the unit. Under the condition of the same period, the vessel with a larger rolling angle corresponds to larger peak gravity component, peak angular displacement, peak linear velocity of block and average power of the unit. In addition, under the same sea conditions, numerical simulations carried out on the rolling motion of 70,000, 100,000, and 150,000-ton bulk vessels and related parameters of the unit, indicating that the instantaneous power of the unit is not uniform in actual sea conditions, but it can output power continuously.

The exploration of renewable energy technology is increasingly important owing to depletion of fossil fuels and the environmental pollution caused by the use of fossil fuels. Converting mechanical energy to electrical energy is one approach to developing renewable energy. However, the harvesting of ultralow-frequency mechanical energy is a challenge that limits the development of energy harvesting technology. To address this difficult problem, this paper proposes a nonlinear hybrid energy harvester in which an electromagnetic generator (EMG) and a triboelectric generator (TEG) are coupled to harvest the mechanical energy from ambient vibrations at ultralow frequencies. The energy harvester is combined with a quasi-zero-stiffness (QZS) mechanism composed of four QZS springs and a linear spring to produce a large-amplitude response and improve the energy harvesting performance. The effect of the mechanical condition (linear, quasi-zero-stiffness and bistable) on the efficiency of energy harvesting is analysed analytically and verified by theoretical and numerical analyses. The dynamics responses of the nonlinear energy harvester influenced by systematic parameters are also dissected. This work provides a guideline for improving the ultralow frequency ambient vibration energy harvesting performance of a TEG through nonlinearity.

In recent years demand for mobile electrical power has been increased and due to this application, energy harvester systems have been developed to convert mechanical energy into electrical energy using smart materials. In this investigation, a novel arrangement of an energy harvester using Magnetic Shape Memory Alloys (MSMAs) is developed. Elements of MSMA are attached to a corrugated beam and their roots are fixed. The way of harvesting energy from this system is based on conversion of vibration motion energy to the magnetic flux gradient. There is a number of copper coils that wrapped around the MSMA elements in a constant magnetic field. If strain or stress field is applied to the MSMA elements, the electrical current is induced to coils. The problem is studied with analytical methods, and for this purpose, MATLAB solver is used. To simulate the behavior of MSMA substance Kiefer and Lagoudas nonlinear model is used. To verify the results, these two arrangements have been analyzed in ABAQUS. To provide the material properties of MSMA elements, UMAT code has been used. It will be shown that size of this MSMA based energy harvester can become smaller with using corrugated beam structure instead of simple cantilever beam.

Electric car does not supply all the electric energy, obtained from the electric network, to the wheels in the form of mechanical energy. During such a transformation, a part of this energy is lost. The article endeavours to determine the energy efficiency of selected electric car. The electric car used for measurements is not from the batch production since that is a vehicle designed at University of Zilina. The efficiency has been observed while driving under the conditions of amended methodology of New European Driving Cycle (NEDC). The measured value of electric car's efficiency is being analyzed from the energy consumption, as well as emission production, points of view.

A steam prime mover with rotary motion of the driving element, or rotor, and continuous operation. It converts the thermal energy of steam into mechanical work. The steam flow proceeds through directing devices and impinges on curved blades mounted along the periphery of the rotor. By exerting a force on the blades, the steam flow causes the rotor to rotate. Unlike the reciprocating steam engine, the steam turbine makes use of the kinetic rather than the potential energy of steam. The performance of the turbine depends on the efficient conversion of steam enthalpy into mechanical power with minimum flow losses. In order to reduce the leakage loss hub/shroud sealing between the stages is considered. The hub/shroud sealing improves the performance of the turbine and higher power is generated from the stages. To simulate the hub/shroud sealing, blades & seals are modelled and meshed separately. The bladed region and hub/shroud seal region are attached by General Grid Interface. The flow domain and mesh generation for seal area needs to be accurate to get the correct interface with blades.

The vehicle plate brake rotor is a pivoting gadget. Slowing down is a cycle which changes over the dynamic energy of the vehicle into mechanical energy which must be scattered as warmth. This paper presents the examination of the temperature and warmth motion at the plate interfaces utilizing an itemized 3-dimensional limited component model of a genuine vehicle brake rotor. Rotor disc are made utilizing CATIAV5R20 and recreated utilizing ANSYS R 20 which depends on the (FEM) analysisHere take cast iron material and seen that the maximum temperature and heat fluxes values for all three geometries like Solid rotor drilled rotor and drilled & slotted rotor respectively like are 589.48 °C, 555.67 °C and 539.97 °C and 2.9e5 w/mm2, 4.96e5 and 5.04e5w/mm2. Here we can clearly observe that drilled & slotted rotor geometry has very high value of heat flux compare to other rotor geometries. Thermal Analysis on car brake rotor is done by using and simulate the different parameters of various materials. The main findings point to experimented the potential investigation of car brake rotor to give best working performance. Two sorts of brake social occasions are being utilized, drum brakes and circle brakes. Drum brakes produce slowing down force on the internal surface of brake drum, the force associated is radially outward to contact the drum. The wheel-wheel studs are associated with the drum, as such when the drum stops the wheel similarly stops. It is important to acquire rough answers for issue instead of accurate shut discover arrangement. It is unimaginable to expect to get investigative numerical answers for some building issues.

Electroactive polymers based on dielectric elastomers are stretchable and compressible capacitors that can act as transducers between electrical and mechanical energies. Depending on the targeted application, soft actuators, sensors or mechanical-energy harvesters can be developed. Compared with conventional technologies, they present a promising combination of properties such as being soft, silent, light and miniaturizable. Most of the research on dielectric elastomer actuators has focused on obtaining the highest strain, either from technological solutions using commercially available materials or through the development of new materials. It is commonly accepted that a high electrical breakdown field, a low Young's modulus and a high dielectric constant are targets. However, the interdependency of these properties makes the evaluation and comparison of these materials complex. In addition, dielectric elastomers can suffer from electromechanical instability, which amplifies their complexity. The scope of this review is to tackle these difficulties. Thus, first, two physical parameters are introduced, one related to the energy converted by the dielectric elastomer and another to its electromechanical stability. These numbers are then used to compare dielectric elastomers according to a general and rational methodology considering their physicochemical and electromechanical properties. Based on this methodology, different families of commercially available dielectric elastomers are first analyzed. Then, different polymer modification methods are presented, and the resulting modified elastomers are screened. Finally, we conclude on the trends enabling the choice of the most suitable modification procedure to obtain the desired elastomer. From this review work, we would like to contribute to affording a quick identification method, including a graphic representation, to evaluate and develop the dielectric materials that are suitable for a desired actuator.

This research paper is an attempt to present an insight into the use of micro electromechanical systems (MEMS) technology harvesting of green energy. One of the common examples of MEMS technology is by utilizing bimorph cantilever beams. Subsequently, it has also been discussed that Bimorph cantilever beam based sensors with high sensing ability could be used for harvesting energy from the physical environment. In this paper, we concentrate on the comparative analysis of the MEMS and piezoelectric materials which are used to design bimorph cantilever beams and convert mechanical energy into electrical energy. Detailed performance analysis of bimorph cantilever beams made of different materials has been carried out through various simulation models. Design and the simulation of bimorph cantilever beam is performed using Comsol multiphysics 5.2. state of art software. Comparative analysis of Lead zirconate (PZT-4D) and Lead zirconate (PZT-7A) has been done in this research to find more suitable material for fabrication of bimorph cantilever beams. PZT-7A is found to provide better electrical output for various analysis performed.

The design of an electromechanical device for fixing cylindrical objects in the spindle units of technological equipment is presented. The new two-stage concept of the clamping process with a separated first stage is developed. The design of the presented mechanism provides advanced capabilities for control and regulation of its operating characteristics. The control system with the possibility of carrying out the first stage of clamping in automatic mode and without connecting to the upper-level control system in a technological machine is proposed. The involvement of electrical devices for the conversion and transmission of energy instead of their mechanical analogues is used as one of the promising ways to increase the performance efficiency of machine units. It helps to simplify and expand control capabilities, as well as reduce energy losses during intermediate transformations. The absence of mechanical energy converters in the proposed structure helps to reduce energy losses on intermediate transformations. The simplicity of the design expands the possibilities of integration of the proposed clamping mechanism into the structure of both new and existing technological machines in order to modernize it. This allows to achieve technical results, such as an expansion of the metalworking machines functionality, increase the level of automation of the clamping process and the accuracy of clamping objects in spindle units. The task is achieved by equipping the jaw of the clamping chuck with a special mechanism for identifying the presence of the object for clamping. For this goal, the clamping jaw is equipped with a probe that is capable of simultaneous force interaction with the object and the plunger. The plunger is rigidly attached to the magnetic element whose magnetic field has the possibility to interact with the magnetic field sensor. The sensor transmits its electrical signals to the control system of the device. The research results are aimed at meeting the requirements for effective control of clamping mechanisms with the possibility of automatic operation according to a preset algorithm for maintenance of optimal characteristics of a clamping process and a wide range of optional settings.

In this study, we developed an approach to additive manufacturing of three-dimensional (3D)-architected CoCrFeNiMn high-entropy alloys by direct ink writing combined with thermal sintering. The 3D-architected CoCrFeNiMn lattices exhibit the outstanding energy absorption capacity that expands the envelope of existing architected materials. Such a high-energy absorption ability originates from the bend-dominated deformation mode of the 3D-architecture as well as the fully-annealed homogeneous microstructure of equiaxed grains, which collectively lead to remarkable strain hardening upon deformation. Our study provides a new avenue for 3D-printing advanced architected materials with extreme mechanical energy absorption for a myriad of structural applications.

With the advent of electronic circuits, automation and hand held devices have become quite common in the life of mankind. Also, to reduce consumption of fossil fuels policy decisions are made wherein electric vehicles ply on the road by 2030. This increasing demand of energy has led to the development of sustainable and even low energy producing sources. In this paper, use of piezoelectric crystals for generation of electricity from pavement systems is discussed. Movement of vehicles on roads impart mechanical energy and piezoelectric crystals have been used to convert this mechanical energy to electrical energy. Using PZT rods, an energy harvesting unit has been developed and the effectiveness of this module has been investigated for pavement system comprising of sand and aggregate layers. Parametric studies have been carried out for different magnitudes of load and frequency of loading. The manuscript also compares the displacements of sand-aggregate system having PZT module at its interface with a system without the module. Experimental studies revealed that the voltage generated is dependent upon the stiffness of the PZT module and the voltage increases with magnitude and frequency of loading.

Due to the near monopoly held by nonlinear energy sinks in the study of targeted energy transfer, little research has been done on the flow of mechanical energy between oscillators with comparable mass. The goal of the present paper is to investigate the flow of mechanical energy between two nonlinearly coupled oscillators with comparable mass that arise due to the breaking of dynamic reciprocity. The first oscillator represents the prototypical linear oscillator (LO), whereas the second oscillator represents a nonlinear oscillator (NO) that is nonlinearly coupled to the LO only. By breaking dynamic reciprocity, one-way energy propagation is achieved in the system, such that energy can only be irreversibly transferred from the NO to the LO. As such, the NO is isolated from the LO for physically reasonable energies whenever it is not directly excited. Moreover, when the NO is directly excited, there exist regimes where the LO, despite being linear and of comparable mass to the NO, behaves like a nonlinear energy sink and parasitically and irreversibly absorbs energy from the NO. The theoretical portion of this works employs direct numerical simulation of the structure to explore the strongly nonreciprocal dynamics and resulting energy transfers. The theoretical results are then verified through experimental measurements of a comparable structure. The present study promotes a new paradigm for investigating energy transfer in mechanical structures and opens the way for passively controlling the flow of energy in complex mechanical systems.

Automotive components are excited dynamically by interior (engine, gear system) and exterior effects (rough street surfaces, aerodynamics). This leads to dynamically induced vibrations which can end in fatigue cracking of components and/or undesirable acoustic emissions. With recent trends in optimizing/minimizing mass of vehicles, vibration problems are becoming an even more pronounced problem. In this research, a way has been investigated to reduce structural vibrations for a simple aluminium cantilever beam object, which is deduced from a cantilever beam of an automotive engine-transmission system. For this academic example the vibration has been reduced by attaching friction strips. The goal is to minimize the overall mass of the structure (cantilever beam plus friction strips) and simultaneously control the vibration amplitude. The energy lost due to the friction between the friction strips and the body of the vibrating beam will reduce the overall mechanical energy of the vibrating system and hence the vibrations will be controlled.

Hysteretic damping of a material or structure loaded within its elastic region is the dissipation of mechanical energy at a rate independent of the frequency of vibration while at the same time directly proportional to the square of the displacement. Generally, reproducing this frequency-independent damping can be computationally complex and requires prior knowledge of the system’s natural frequencies or the full time history of the system’s response. In this paper, a new model and numerical procedure are proposed whereby hysteretic material damping is achieved in the time domain. The proposed procedure is developed based on modifying the viscous model through a correction factor calculated exclusively using the local response. The superiority of the proposed approach lies in its ability to capture material hysteresis without any knowledge of the eigen- or modal frequencies of the system and without knowledge of the past time history of the system’s response or the characteristics of any excitation forces. A numerical procedure is also presented for implementing the proposed model in vibration analysis. The simplicity of the approach enables its generalisation to continuous systems and to systems of multi-degrees of freedom as demonstrated herein. The proposed model is presented as a correction to the viscous damping model which makes it attractive to implement into commercial finite element package using user-defined element subroutines as demonstrated in this study.

The blades of a hydrokinetic turbine have a great impact on its performance due to they are the elements responsible for capturing the kinetic energy from water and transform it into rotational mechanical energy. In this work, numerical analyses on the performance of a multi-element blade section were developed. The lift and drag coefficients (CL and CD, respectively) of the hydrofoils with traditional and multi-element configurations were studied. For this purpose, 2D numerical analyses were conducted by using JavaFoil code. S805, S822, Eppler 420, Eppler 421, Eppler 422, Eppler 423, Eppler 857, Wortmann FX 74-CL5-140, Wortmann FX 74-CL5-140 MOD, Douglas/Liebeck LA203A, Selig S1210, Selig S1223 and UI-1720 profiles were tested. The results indicated that the Eppler 420 multi-element hydrofoil provided high efficiency to the turbine. This was attributed to its higher relationship between the maximum CL and CD (CLmax /CD), which was equal to 47.77, compared to that of the Selig S1223 profile (39.59) and other hydrofoils studied. Therefore, the final optimized blade section selected was an Eppler 420 multi-element hydrofoil with a flap chord length of 70% of that of the main profile. The hydrodynamic and structural designs of the optimized blade section were validated with detailed 3D numerical models, through ANSYs Fluent software. The fluid and structural domains were connected using one-way coupling. The influence of the blade geometry and the operational parameters on the stresses supported by the blades were found by analyzing the fluid-structure interaction. From the numerical analyses conducted, it was observed that the blades did not exhibit structural fails. In this regard, the multi-element hydrofoil might be used for the design of a horizontal-axis hydrokinetic turbine with a high efficiency.

This study aims to determine the performance of the dynamometer design as a measure of mechanical power on a rotary friction welding machine. The design of the dynamometer includes the design, manufacture, calibration, and testing of the dynamometer. The design and manufacture of strain dynamometers is adjusted to the motor of the rotary friction welding machine at the University of Riau's Mechanical Engineering Production Technology Laboratory. The design of the strain dynamometer has a dimension of 175 mm × 3 mm × 50 mm and serves to determine the motor torque value with the help of a 120 ohm strain gauge sensor. The device designed is equipped with an electrical microcontroller device and an optocoupler sensor to measure the angular speed of the motor. Next, the dynamometer performance testing is performed on the rotary friction welding machine. The results of testing in the rotary welding process, the greater the pneumatic pressure exerted during welding, the greater the measured power. The largest measured power value is 2452.92 Watt in the forging process, and the smallest measured power value is 2050.24 Watt in the first time of the initial motor rotation. After doing the research, it can be concluded that the tools designed and built can work and have a fairly good performance.

Triboelectric energy harvester (TEH) is an emerging technology that has been recently demonstrated to harvest mechanical energy. The TEH can be fabricated in various configurations due to their fle...

Gust response of aircraft can become a potential energy source thanks to energy harvesting (EH) methods, one of which can transform mechanical energy to electrical energy, applying piezoelectric ceramic transducers (PZTs). Harvested electrical energy needs to be evaluated for reuse, but current beam-model-based evaluation methods of EH performance for a plate model are insufficient because the plate is two-dimensional. This paper proposes two types of EH evaluation methods to analyze the gust exciting low-aspect-ratio plate wing model. One method focuses on the ratio of electrical energy to kinetic energy, and the other reflects energy output density per unit weight. These two methods can reveal the higher energy harvesting efficiency positions when utilizing PZTs on the flight EH system. Plate model, three-dimensional doublet lattice unsteady aeroelastic method and piezoelectric equation are used to build piezoaeroelastic wing model, and 1-cosine discrete gust load is the base excitation. A time-domain aero-electro-elastic state-space equation of the low-aspect-ratio piezoaeroelastic plate wing model is established, and the time-history analysis is used to solve the EH output. Results show that EH outputs are influenced by various parameters including load resistance, PZT thickness, gust intensity and wavelength, and PZT location variation. The optimal values of the proposed EH efficiency evaluation methods are found and explained.

Improving the efficiency and reliability of nodes and parts of transport vehicles, aimed at intensifying their productivity, is one of the main tasks of transport engineering. An increase in transport productivity during operation leads to the fact that its components and parts are inevitably exposed to significant loads and energies. Moreover, the repayment of the latter in turn leads to the dissipation of mechanical energy into heat in small volumes of the friction unit, which inevitably leads to heating of its friction pairs. Therefore, one of the responsible and most loaded components of transport vehicles includes brake devices that ensure operational safety and significantly affect the level of reliability. Based on basic studies of braking devices of mechanisms and machines by many scientists, it can be concluded that the solution to the problem of creating a reliable friction pair of modern highly loaded brakes of mechanisms and machines is possible only with the use of more heat-resistant materials and with the simultaneous development of brake designs that ensure the formation of lowest heating temperatures friction surfaces. This article is devoted to increasing the braking efficiency of transport vehicles using new friction composite materials based on carbon-carbon with a pyrocarbon matrix and studying their tribotechnical characteristics. From the above it follows the need to study the influence of the main factors on the reduction of steady temperatures in the contact zone of friction elements. The presence of a relationship between the temperature in the contact zone of the friction pair, time, cooling method, and robot mode predetermined the solution of the problem of establishing the general dependences of this connection. Researchs were conducted for a new carbon-composite friction material with increased heat conductivity, heat capacity and heat transfer. Improving the thermophysical characteristics of the friction materials of brake devices raised the question of studying the influence of the main factors of the braking process on the magnitude and nature of the change in the coefficient of friction. And finally, the use of the new carbon-composite friction material has set the task of a qualitative study of the frictional properties and a quantitative study of the wear of the friction surfaces of the braking device with the new friction material.

Energy-efficient train operation is regarded as an effective way to reduce the operational cost and carbon emissions in metro systems. Reduction of the traction energy and increasing of the regenerative energy are two important ways for saving energy, which is closely related to the train timetable and driving strategy. To minimize the systematic net energy consumption, i.e., the difference between the traction energy consumption and the reused regenerative energy, this paper proposes an integrated train operation approach by jointly optimizing the train timetable and driving strategy. A precise train driving strategy is presented and the timetable model considers the headway between successive trains, the distribution of the trip time, and passenger demand in this paper. In addition, a distributed regenerative braking energy model is proposed, based on which the integrated optimization model is formulated. Then, a two-level approach is proposed to solve the problem. At the driving strategy level, the train control problem is transferred into a multi-step decision problem and the Dynamic Programming method is introduced to calculate the energy-efficient driving strategy with the given trip time. As for the timetable level, the trip times and headway of trains are optimized by using the Simulated Annealing algorithm based on the results of dynamic programming method. The timetable optimization level balances the mechanical traction energy of multi-interstations and the amount of the reused regenerative energy such that the net mechanical energy consumption of the metro system is minimized. Furthermore, two numerical examples are conducted for train operations in the peak and off-peak hours separately based on the real-world data of a metro line. The simulation results illustrate that the proposed approach can produce a good performance on energy-saving.

We present an open-source framework for developing optimal leg designs for walking robots. The leg design parameters (e.g. link lengths, transmission ratios, and spring parameters) are optimized for a user-defined metric such as the minimization of energy consumption or actuator peak torque, enabling the user to better navigate through the high-dimensional and unintuitive design space. Our approach uses the single rigid body dynamics trajectory optimization tool TOWR to generate realistic motion plans. The planned predefined forces and motions are then used to identify actuator velocities and torques. Next, the leg design parameters are optimized using a genetic algorithm. The framework was validated by comparison with measured data on the ANYmal quadruped robot for a trotting motion,with errors in cumulative joint torque and mechanical energy each below 8% per gait cycle. Optimization of the ANYmal link lengths demonstrate that reductions in joint torque, mechanical energy, and mechanical cost of transport in the range of 5-10% are attainable., IEEE Robotics and Automation Letters, 5 (4), ISSN:2377-3766

The water turbine is a device that converts water flow energy into shaft mechanical energy. Before being converted into mechanical energy in the turbine, the potential energy needs to be converted into kinetic energy first. The vortex will move the turbine blades which cause the runner to rotate so that there is a change in the kinetic energy of the water into mechanical energy in the turbine which is used to drive the generator and then into electrical energy. The purpose of this research is to analyze the torque that occurs on the shaft and turbine power. Water is flowed to the test with a pump through a control valve. The water flow is read by a rotameter attached to the pipe to the upper reservoir, while the torque is measured using a load cell, while the rotation is measured using a photo sensor interrupt to read the movement of the counter wheel. Data from load cell and photo sensor interruptor is read using Arduino Uno then the data is stored on laptop in excel file using plx-daq software. The minimum torque for the 8 blades is 9,12 kg.mm and 7.61 kg.mm for 6 blades at a water flow rate of 90 l / min. The maximum torque occurs at the 8 blades of 10.06 kg.mm while the maximum torque at blade 6 is 9,12 kg.mm at the same water flow rate of 150 l / min. The minimum turbine power for the 8 blades is 0.47 W and 0.27 W for the 6 blades at a water flow rate of 90 l / min. The maximum turbine power at blade 8 is 1.03 W, while the maximum power at blade 6 is 0.91 W at the same water flow rate of 150 l / min. From the data analysis, it can be seen that the power for the turbine with the number of blades 8 tends to be greater than the power for the turbine with 6 blades, but if the percentage increases in power between the 8 blades and 6 blades the trend decreases even though the flow rate is increasing.

Salter’s Duck can convert wave energy to mechanical energy with high efficiency up to 90%. The limitations and challenges in the usage of Salter’s Duck for energy production include preventing hydraulic system from the risk of leaking hydraulic oil and removing complex huge fixed bracket. This paper presents the conceptual design and an experimental investigation of a mechanical power-take-off (PTO) system for the floating Salter’s Duck. The PTO system is fully installed inside of the Salter’s Duck. It consists of double counter-rotating flywheels converting the bi-directional rotation of the wave energy converter into a stable unidirectional rotation that drives a rotary generator to produce electricity. The bi-to-unidirectional function is achieved through inertial wheels, thus the novel PTO system is free of large supporting structures and hydraulic cylinders. In this paper, a detailed conceptual PTO design is proposed firstly. Further, the influence of the swing amplitude and rotation period of the wave energy converter on the power extraction efficiency is investigated. Then, the influence of the electrical load on the power-extraction efficiency is researched. In the end, the effect of the speed increasing ratio on the mechanical efficiency is examined. The experimental results show that the new type of generator mechanism can produce electricity stably.

In this study, we designed and fabricated a poling-free piezoelectric nanogenerator using bio-based polymer and filler, a poly(l-lactic acid) (PLLA)/vitamin B2 (VB2) composite film. The addition of VB2 to PLLA led to improved crystallinity and enhanced the molecular orientation of PLLA, resulting in a significantly enhanced output performance of the PLLA/VB2 nanogenerator. The proposed nanogenerator provides a maximum power density of 75.68 mW cm−3, which is approximately 28.7 times higher than that of pure PLLA nanogenerator. Moreover, the PLLA/VB2 nanogenerator exhibits good electrical responses under both mechanical and acoustic stimulations. The collected mechanical energy from the motion of human joints can power up several LEDs. The PLLA/VB2 nanogenerator can sensitively detect sound frequency from 1 to 27 kHz. Thus, it has great application potential in ambient mechanical and acoustic energy harvesting, wearable devices, and human–machine controlling systems.

The results of a numerical study of the thermal and acoustic energies released during the collapse of a single spherical cavitation bubble in water at a pressure of 10 bar and a temperature of 20°С are given. In the model used, we take into account the thermal conductivity of the vapor in the bubble and the surrounding liquid, heat transfer, evaporation/condensation on the surface of the bubble, and the fluid compressibility. The conversion of mechanical energy into heat due to the fluid viscosity is not accounted for. When the bubble collapses, the energy of acoustic radiation due to radial pulsations of the bubble is shown to be approximately nine times greater than the energy spent on heating the liquid. The value of this energy is proportional to the cube of the initial bubble radius.

In the last decades, numerous mechanical energy sources have been utilized as primary energies to produce electricity by using different energy harvesting technologies, such as electromagnetic, and piezoelectric technologies. Among these mechanical energy sources, fluid flow energy, defined by water flow and airflow energies, is one of the most important and wide-used renewable energy sources, which is available in nature under the form of raindrops, streams, ocean waves and wind energies. Since the first introduced in 2012 by Wang’s research group, the triboelectric nanogenerator (TENG) has become one of the most vital innovations in harvesting energy technologies. Many TENGs devices have been developed and demonstrated its potential in harvesting fluid flow energy. Here, a review of the fluid-based TENG (F-TENG) is presented, including water-based and air-based, with the fundamental theories, basic mode of operations, its current designs, and application. The development of F-TENG is demonstrated via the divers of design structure, high potential application for power generation, and high sensitivity for self-powered sensing systems. F-TENG shows promising potential for large-scale application, and hybrid with other energy harvesting technologies. Besides, this article also considers the recent difficulties which reduce the performance of F-TENG, then presents the ways for improving their efficiencies. Finally, this study provides a point of view based on the facing challenge and future development trend of the F-TENG.

The pump is a machine that receives power through a rotating shaft and converts the mechanical energy into pressure and kinetic energy of fluid. Therefore, it is widely used in various industrial fields, and many studies have been conducted to improve the performance of pumps. In this paper, the effect of the gap between the impeller and the volute tongue on the performance and pressure fluctuation of the double suction pump was investigated. Numerical analysis was conducted using the commercial code ANSYS CFX ver. 18.1. Three different values of gap between the impeller and the volute tongue, 0.067%, 0.145% and 0.224% of the impeller diameter were considered.

An L type broadband piezoelectric energy harvesting device was proposed in this paper, and the finite element model of L-type piezoelectric vibrator is established and simulated. It shows that the voltage corresponding to the first and third order resonant frequency is 0.06 V and 0.183 V, respectively, although higher than that of the ordinary piezoelectric vibrator, the voltage of the first mode and third mode for the piezoelectric vibrator is not close, which has little effect to broaden the bandwidth. Consequently, the simulation model for multi-cantilever piezoelectric vibrator was established, and its structural sizes were optimized, and it was obtained very close to first and third order resonant voltage, the bandwidth of the vibrator was broadened to 12.5 Hz. The multi-cantilever piezoelectric vibrator can be applied in a variety of devices for the collection of mechanical energy, and to provide a research foundation for the development of intelligent structures with self-sufficiency.

© 2020 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes,creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. Traditional industry is experiencing a worldwide evolution with Industry 4.0. Wireless sensor networks (WSNs) have a main role in this evolution as an essential part of data acquisition. The way in which WSNs are powered is one of the main challenges to face if industry wants to achieve the digital transformation. Energy harvesting technologies are one of the possible solutions to this challenge. The main purpose of this paper is to present a novel method to taxonomize knowledge in the field of mechanical energy harvesting to enhance the use of energy harvesting technologies in industrial applications. The methodology is based on the analysis of key parameters and performance metrics for existing technologies. The taxonomy is applied to rail axles in order to select the energy harvesting technology that is more appropriate for this specific location, demonstrating the potential of mechanical energy harvesting technologies (MEHTs) for the railway industry, as a use case of industrial environment. In addition, the taxonomy allows to identify the upcoming challenges for research purposes while analyzing the compatibility among mechanical energy harvesting technologies in order to create hybrid harvesters.