Hasil untuk "Mechanical engineering and machinery"

CHEN Xiulin, WANG Sanhu, ZOU Yangju

This paper addresses the issues of floating high voltage at light loads and insufficient cross-regulation in open-loop high-isolation multi-output power supplies. It initially introduces methods of separate winding arrangements and core projection coincidence to reduce distributed capacitance and leakage inductance in transformers. Subsequent analysis reveals the impact of distributed capacitors on converter gain based on the fundamental harmonic wave analysis method. Additionally, a series compensation method is utilized to mitigate this impact of leakage inductance on convertor gain. This combination leads to the development of a CLLC resonant converter with an asymmetric structure. Finally, the paper presents the development of a 4-output prototype with a total output power of 420 W. Testing results indicate that both the primary and secondary sides of transformer meet an AC18 kV isolation requirement. The voltage accuracy of power output across the full load range is controllable within ± 10%. In fault mode, the faulty branch actively shuts off the output, while normal functioning is maintained in the other branches, verifying the correctness of the proposed design scheme.

Shi Yalei, Wang Liangwen, Liu Yiyang et al.

Wrap-around packaging is widely used in logistics and transportation packaging. The development of a self-propelled winding and packaging robot can significantly push up the technological progress of the industry, and the key to the development of this robot is the design of the packaging film fixing device. In this study, we propose a packaging film fixing device for a self-propelled wrap-around robot, including a cylinder driven articulated arm, a clamping and turning mechanism, a press tape cutting mechanism, and a tape unfolding mechanism. Based on the mechanism design according to the work requirements, SolidWorks is used to model the structure in three dimensions, and the multi-body kinematic analysis is performed by Adams to verify the feasibility of the mechanism. The simulation results show that the running trajectory of the belt chuck conforms to the planned path and meets the design requirements. The structural design and simulation study in this study provide the basis for the subsequent practicalization of the winding and packaging robot.

Federico Capra, Diego Abalos, Stefania Codruta Maris et al.

Abstract Digestate, a by‐product of biogas production, is widely recognized as a promising renewable nitrogen (N) source with high potential to replace synthetic fertilizers. Yet, inefficient digestate use can lead to pollutant N losses as ammonia (NH3) volatilization, nitrous oxide (N2O) emissions and nitrate (NO3−) leaching. Cover crops (CCs) may reduce some of these losses and recycle the N back into the soil after incorporation, but the effect on the N balance depends on the CC species. In a one‐year field study, we tested two application methods (i.e., surface broadcasting, BDC; and shallow injection, INJ) of the liquid fraction of separated co‐digested cattle slurry (digestate liquid fraction [DLF]), combined with different winter cover crop (CC) options (i.e., rye, white mustard or bare fallow), as starter fertilizer for maize. Later, side‐dressing with urea was required to fulfil maize N‐requirements. We tested treatment effects on yield, N‐uptake, N‐use efficiency parameters, and N‐losses in the form of N2O emissions and NO3− leaching. CC development and biomass production were strongly affected by their contrasting frost tolerance, with spring‐regrowth for rye, while mustard was winter killed. After the CCs, injection of DLF increased N2O emissions significantly compared with BDC (emission factor of 2.69% vs. 1.66%). Nitrous oxide emissions accounted for a small part (11%–13%) of the overall yield‐scaled N losses (0.46–0.97 kg N Mg grain−1). The adoption of CCs reduced fall NO3− leaching, being 51% and 64% lower for mustard and rye than under bare soil. In addition, rye reduced NO3− leaching during spring and summer after termination by promoting N immobilization, thus leading to −57% lower annual leaching losses compared with mustard. DLF application method modified N‐loss pathways, but not the cumulative yield‐scaled N losses. Overall, these insights contribute to inform an evidence‐based design of cropping systems in which nutrients are recycled more efficiently.

Walter Leal Filho, Diogo Guedes Vidal, Maria Alzira Pimenta Dinis et al.

Tianyi Zhang, Xiaofeng Yang, Yujie Shen et al.

Inerters, a new type of mass element, have been successfully applied in various fields, such as in automotive and civil engineering. The development of a new element, named a mechatronic inerter, which consists of a ball-screw inerter and permanent magnet electric machinery, proves the feasibility of adopting electrical element impedances to simulate corresponding mechanical elements. In this paper, the structures of the bridge electrical network and series-parallel electrical network and their impedance characteristics are first introduced. Then, a seven-degree-of-freedom vehicle model is established. In addition, by comparison with passive suspension, a bridge network and a series-parallel network with various basic topologies are used to improve the vibration isolation performance of mechatronic inertial suspension, and the advantages of the bridge network (a) are demonstrated. Finally, a bridge electrical network (a) was designed and a real vehicle test was carried out. The test results showed that the mechatronic inertial suspension based on the bridge network (a) was superior to the passive suspension; the RMS (root-mean-square) values of the suspension working space and dynamic tire load of the left rear wheel suspension were reduced by 21.1% and 6.3%, respectively; and the RMS value of the centroid acceleration was improved by 1.8%.

Changsong Li

W. Hsieh, J. Garza‐Reyes, P. Wong

This special issue contains 10 extended papers presented in the 8th and the 9th Multi-International Conference on Engineering and Technology Innovation (IMETI), held in Taiwan in 2019 and 2020, respectively. These articles present the recent advances in artificial intelligence, mechatronics, smart manufacturing, advanced robotic, and some important topics in modern factories. Artificial intelligence technologies such as Expert systems, Artificial Neural Networks, Fuzzy Theory, and Heuristically Search are profoundly changing the machinery industry in countries around the world. Artificial intelligence is applied to all aspects of the machinery industry, such as product design, process determination, production management, fault diagnosis, etc. Manufacturing is the cornerstone of a factory, and enters a new era along with the development of artificial intelligence. To promote the development of modern factory, artificial intelligence will play a strong supporting role. In recent years, artificial intelligence technology has become a research hotspot of manufacturing and industry, and has received extensive attention from academic and industrial circles at home and abroad. However, the research on artificial intelligence in the field of machinery is still at a preliminary stage. How to use artificial intelligence to build an efficient and intelligent manufacturing system, still faces many scientific challenges and technical problems. This special issue is devoted to promoting academic exchanges and advanced research progress of artificial intelligence in the field of the modern factory. It is expected this issue will inspire the authors and broader the manufacturing community to continue their contribution to the modern and future industry. It is my great pleasure and honor to organize this Special Issue in Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture. Also, we would like to express my deepest thanks to the reviewers for taking their time to comment on the papers. Moreover, We would like to thank all the authors who have contributed their original works to this issue. Lastly, special thanks must be extended to the Editor in Chief/Prof. P. G. Maropoulos and the production team of the journal, for their kind and professional support to the publication of this Special Issue.

Takashi OYAMA, Effendi MOHAMAD, Teruaki ITO

Human movements vary on trial-by-trial due to signal-dependent noise that is added to motor commands and provokes errors of movements. In some motor tasks, humans have to produce precise movements with overcoming of the noise. This study aimed at considering the motor criteria taking into account movement errors. Three factors affecting movement errors in arm repetitive movements were investigated: the viscous force field, hand laterality, and signal-dependent noise. In the measurement experiment, the participants were asked to move their right and left hands between the target areas specified as the motor task. Pseudo null, positive (resist), and negative (assist) viscous force fields were set in the workspace of the motor task. A two-way analysis of variance involving two factors, hand (right and left) and viscosity (null, resist, and assist), in the movement error was conducted, and it revealed significant main effects of hand and viscosity, and a significant interaction between them. The data obtained from the measurement suggested consistent characteristics for the shape of the paths of the movement trajectories. A simulation experiment was conducted to investigate the shape characteristics which are regarded as the nature of the human motor control system. Under the assumption of signal-dependent noise, results of the experiment revealed that the shape characteristics are associated with lower variance of a movement error directly relating the task achievement rather than an error of a movement endpoint. The lower variance of the movement error is of greater significance as the criteria of motor planning compared to the smoothness of the movement.

Shahriyar Ghazanfari Holagh, Mohammad Ali Abdous, Hamidreza Rastan et al.

Heat transfer enhancement techniques are accompanied by pressure drop amplification, detrimentally affecting their performance; entropy generation analysis is an effective approach to assess heat transfer enhancement along with resulting pressure drop. Current study investigates and compares the performance of micro-fin (as a passive enhancement technique) and smooth tubes during flow condensation (for R134a refrigerant) through conducting entropy generation analysis. First, the impact of geometrical and operating variables on pressure losses and heat transfer contributions to entropy generation and total generated entropy inside both types of tubes is examined. Then, the conditions at which the application of micro-fin tubes in lieu of smooth ones is justifiable and of superior performance are identified utilizing entropy generation number. The simulation results indicate that entropy generation enhances in the micro-fin tubes as tube diameter, mass velocity, vapor quality, and wall heat flux rise, and saturation temperature declines. The same is observed in the smooth tube except for the mass velocity; an increase in this parameter leads to a decreasing-increasing trend in entropy generation. Moreover, the entropy generation number results indicate that applying micro-fin tubes rather than smooth ones is justifiable, i.e., has better performance, at lower mass velocities and vapor qualities, but higher saturation temperatures and wall heat fluxes.

H. Khan, F. Khan, Surat Khan et al.

High-speed rotating mechanical machinery is a developed, mature and reliable technology for many engineering applications. In high-speed permanent magnet machines, the rotor’s permanent magnet PM is not strong enough to withstand the centrifugal force resulting from excessive rotational speed; thus, the PM material must be protected by a non-magnetic alloy sleeve. This paper presents a novel high-speed PM machine with solid rotor PM covered by a titanium retaining sleeve. The rotor stress condition is simplified as a plane stress problem according to the strength measurement of solid PM rotors in the high-speed PM motors. The analytical formulas for rotor stress are presented based on the polar coordinate displacement method. The proposed model is compared with a conventional model having auxiliary slots in stator teeth. Using a finite element analysis environment, the performance analysis shows that the proposed design has reduced magnet eddy current loss, cogging torque, and iron losses. The initial design is also optimized using a deterministic optimization algorithm that increases output torque by 26% compared to the initial design.

G. Storti, Felipe Wenzel da Silva Tuckmantel, T. Machado

Timur Rizovich Ablyaz, Preetkanwal Singh Bains, Sarabjeet Singh Sidhu et al.

In the present work, a hybrid magnetic field assisted powder mixed electrical discharge machining had been carried out on the Aluminum-Silicon Carbide (Al-SiC) metal matrix composite. The aim of the study was to obtain higher surface finish, and enhanced material removal rate. The dielectric mediums employed were plain EDM oil, SiCp mixed and graphite powder mixed EDM oil for flushing through the tube electrode. The magnetic field intensity, discharge current, T-on/off duration and type of dielectric were the control variables used for present investigation. From the results, it was observed that the machining variables for instance, discharge current, T-on/off duration and type of dielectric conditions remarkably affected the material removal rate, micro-hardness and surface roughness of the machined composite material. The MRR augmented considerably with an increase in the magnetic field intensity along with peak current. Subsequently, the composite with lesser vol.% of SiC particulates witnessed sharp rise in MRR in maximum magnetic field environment (0.66T). In addition, quality of the machined surface improved significantly in graphite powder mixed dielectric flushing condition with intermediate external magnetic field environment. Besides, an enhancement of micro-hardness was quantified as compared to base material due to the transfer of the material (SiCp) during powder mixed ED machining.

R. Glienke, M. Schwarz, A. Ebert et al.

Many mechanical joints in steel structures use conventional bolts. Nevertheless, this proven joining technology has some significant disadvantages. These basically include the high levels of scatter during application of the assembly preload using the torque‐controlled tightening process, the risk of loosening during cyclic loads due to transverse displacement of the components and the low fatigue resistance under axial loading. Lockbolt technology was invented as long ago as the 1930s and mainly used for the aviation and space industry because of its evident advantages. This joining technology has been constantly further developed in response to the most diverse demands from sectors such as aviation, commercial vehicles, rail vehicles, agricultural machinery, defence technology and steel structures. The application of lockbolt technology, which is primarily used in mechanical engineering, was in most cases based on individual studies, since no consistent rules and guidelines were available for the design and execution of lockbolt connections in steel structures. Within the scope of several public research projects funded by the AiF (German Federation of Industrial Research Associations) and conducted by the iGF (Industrial Collective Research) organization as well as through approval investigations, the Fraunhofer Institute for Large Structures in Production Engineering (IGP) has successively developed the necessary design rules according to the EN 1993 standard (Eurocode 3) for use in structural connections. These design rules will be presented within the context of this article in order to make the benefits of this joining technology available to other users. In addition, insights into the use of technical approvals will be presented together with some current applications.

P. Franco, J. Jodar

Daniele Bigoni, Yuming Chen, N. G. Trillos et al.

This paper suggests a framework for the learning of discretizations of expensive forward models in Bayesian inverse problems. The main idea is to incorporate the parameters governing the discretization as part of the unknown to be estimated within the Bayesian machinery. We numerically show that in a variety of inverse problems arising in mechanical engineering, signal processing and the geosciences, the observations contain useful information to guide the choice of discretization.

Adrian Seck, Silvio Geist, Janneck Harbeck et al.

High-fogging is widely used to rapidly increase the power outputs of stationary gas turbines. Therefore, water droplets are injected into the inflow air, and a considerable number enter the compressor. Within this paper, the primary process of droplet evaporation is investigated closely. A short discussion about the influential parameters ascribes a major significance to the slip velocity between ambient gas flow and droplets. Hence, experimental results from a transonic compressor cascade are shown to evaluate the conditions in real high-fogging applications. The measured parameter range is used for direct numerical simulations to extract evaporation rates depending on inflow conditions and relative humidity of the air flow. Finally, an applicable correlation for the Sherwood number in the form of <inline-formula> <math display="inline"> <semantics> <mrow> <mi>S</mi> <mi>h</mi> <mo>(</mo> <mi>R</mi> <msup> <mi>e</mi> <mrow> <mn>1</mn> <mo>/</mo> <mn>2</mn> </mrow> </msup> <mi>S</mi> <msup> <mi>c</mi> <mrow> <mn>1</mn> <mo>/</mo> <mn>3</mn> </mrow> </msup> <mo>)</mo> </mrow> </semantics> </math> </inline-formula> is suggested.

Kotaro NAKAMURA, Takehiko MURAMATSU, Takashi OGAWA et al.

Natural gas-fired combined cycle power plants (NGCC) have the advantages of high efficiency and low CO2 intensity compared to coal-fired power plants. When variable renewable energy sources are introduced to the grid in large quantities, the NGCC is expected to have rapid start-ups, rapid shutdowns, and increased partialload operations to stabilize the grid. Due to these temporary operations, the ratio of NO2/NOX in the NGCC exhaust gas changes significantly. In general, when the NO2/NOX ratio is high, the efficiency of the de-NOX systems decreases. Moreover, the performance of de-NOX systems has a transient response due to changes at the catalyst surface and the adsorption of NH3. Considering the trajectory of increased variable renewable energy, it is necessary to develop an efficient NOx removal system that is effective over a wide range of NO2/NOX ratios. In the modeling of de-NOX system performance, this study extends the general Eley-Rideal reaction between adsorbed NH3 and gas-phase NOX to include the existence of O2, H2O, CO2, and transient NO2 in the exhaust gas along with changes in redox sites (i.e., V5+=O and V4+-OH). A two-dimensional transient numerical simulation code was developed and adapted using experimental results obtained from treating simulated NGCC exhaust gas using a commercial honeycomb-shaped selective catalyst. Numerical simulations incorporating the empirically determined kinetic equations accurately predict the transient and equilibrium concentrations of NOX and NH3 exiting a honeycomb catalyst even under gas conditions including high NO2.

C. Anwar, Willy Tambunan, Suwardana Gunawan

In the current industrial era a lot of progress from machine technology or methods used by companies in their production systems. So that the system of production and productivity in the company takes place effectively, safely, and efficiently. One way to achieve this is by paying attention to the occupational health and safety (K3) of the employees in the company. The identification of work accidents used in this study uses the Hazard and Operability Study (HAZOP) method. In the work system in the PDAM there is work that is vulnerable to work accidents such as in the field of maintenance or maintenance on machinery, water treatment production systems, and work carried out in the workshop. From the results of field observations at the PDAM Tirta Kencana workshop and interviews with workers, there were 50 potential hazards that existed at the PDAM Tirta Kencana workshop and were then classified according to the type of sources into 12 sources of hazards. There are 3 levels of work accident risk from hazard sources obtained from the risk matrix assessment, which has the potential to cause work accidents. The level of risk is an extreme risk of 1 source of hazard, a high risk of 5 sources of hazard, and a moderate risk of 6 sources of hazard. The proposal of the results of this study is to conduct OSH training, conduct work supervision, and perform maintenance on machinery and equipment.

Mario Lucio Puppio, Martina Ferrini

The seismic rehabilitation of existing r.c. and masonry buildings is a topical issue in Civil Engineering. A useful technique consists in the introduction of external bracing system. This kind of intervention can be improved throughout the introduction of dissipative links, here investigated with the help of some examples.. The links are made of common steel profiles: length, geometry and its disposition are considered as design parameters. A general procedure of link-bracing optimization is proposed applying a set of identical external restraints . The adopted dissipative links consent a cheaper and effective design both in terms of ULS than in DLS: the damages are addressed in a small area permitting an easy replacement of the links in case of earthquake.

Ming Zhong, Lu Jin, Jiyu Xia et al.

Traditional seawater desalination requires high amounts of energy, with correspondingly high costs and limited benefits, hindering wider applications of the process. To further improve the comprehensive economic benefits of seawater desalination, the desalination load can be combined with renewable energy sources such as solar energy, wind energy, and ocean energy or with the power grid to ensure its effective regulation. Utilizing energy internet (EI) technology, energy balance demand of the regional power grid, and coordinated control between coastal multi-source multi-load and regional distribution network with desalination load is reviewed herein. Several key technologies, including coordinated control of coastal multi-source multi-load system with seawater desalination load, flexible interaction between seawater desalination and regional distribution network, and combined control of coastal multi-source multi-load storage system with seawater desalination load, are discussed in detail. Adoption of the flexible interaction between seawater desalination and regional distribution networks is beneficial for solving water resource problems, improving the ability to dissipate distributed renewable energy, balancing and increasing grid loads, improving the safety and economy of coastal power grids, and achieving coordinated and comprehensive application of power grids, renewable energy sources, and coastal loads. Keywords: Desalination, Distribution network, Power grids, Multi-source multi-load, Coordinated control