1,721,199 research outputs found
Actuators
No full textActuators (ISSN 2076-0825) provides an advanced forum for the science and technology of actuators and control systems. It publishes reviews (including comprehensive assessments on complete actuator products), regular research papers and short notes. Our aim is to encourage scientists to publish their experimental and theoretical results in as much detail as possible. There is no restriction on the length of the papers. The full experimental details must be provided so that the results can be reproduced. There are, in addition, unique features of this Journal:
•Manuscripts regarding research proposals and research ideas will be particularly welcomed.
•Electronic files and software regarding the full details of the calculation and experimental procedure, if unable to be published in a normal way, can be deposited as supplementary material.
•Manuscripts concerning summaries and surveys on research cooperation and projects (that are funded by national governments) to give information for a broad field of users
PROCEEDINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS. PART C, JOURNAL OF MECHANICAL ENGINEERING SCIENCE
No full textThe Journal of Mechanical Engineering Science advances the understanding of both the fundamentals of engineering science and its application to the solution of challenges and problems in engineering.
It is dedicated to the publication of high quality papers on all aspects of mechanical engineering science and is a member of the Committee on Publication Ethics (COPE)
Transactions of Famena
No full textTransactions of FAMENA pubblica lavori scientifici originali, Note tecniche, Articoli di Review su argomenti particolari e lavori professionali nel campo dell'Ingegneria Meccanica. E' da oltre 10 anni indicizzata WOS e SCOPUSTransactions of FAMENA will publish original scientific papers, preliminary technical notes, subject reviews and professional papers in the field of Mechanical Engineering. It has been WOS and SCOPUS indexed for over 10 years
Load Cell Training for the Students of Experimental Stress Analysis
No full textMany numerical models are nowadays available for the structural analysis of complexly shaped structures. However, a critical problem consists of the estimation of the actual loads that a structure withstands. The most proper way to determine them under service conditions consists of executing in-field tests, where load cells have an important role. This article deals with a didactic project at the University of Bologna, focused on the development of strain gage load cells, from design to calibration and use. Details are provided on the course units involved and on the levels of teaching, and three case studies are presented. Two case studies deal with the design of decoupled load cells, using simple beam geometry. Students had the opportunity to become confident with the principles ofmechanics and to tackle the not trivial activities like calibration by decoupled load application and determination of the related matrices. The third one deals with the development of a load cell for impact loads, where the students had the chance to observe a practical application of the studied Wheatstone bridge connection, to participate in on-field tests, and to better understand the close relationship between experimentation and design
Low Cycle Fatigue behaviour and anisotropy of two steels for turbogenerator coil retaining rings and rotors
No full textTurbogenerator rotors and coil retaining rings (CRR) are typically subjected to low cycle fatigue (LCF). The rotor contains uniformly spaced longitudinal slots, where copper conductors are packed: at the nominal speed of 3000 rpm a great centrifugal force acts on the copper conductors that must be restrained by CRRs, shrunk fitted onto the body over the coils. Thus, at each on-off transitory (10,000 – 15,000 in the whole machine life) both the rotor and the CRR are subjected to a cyclic load. Several contributions report the mechanical properties of the typically used steels for rotor and CRR manufacturing, but none deals with their characterization under LCF in strain controlled conditions, while investigations on the anisotropy were performed just on CRR steels in load controlled conditions. This research aims at determining the main parameters describing the LCF performance of two widely applied steels for rotors and CRRs, investigating also the anisotropy in the dynamic behaviour: for this purpose an extensive experimental campaign was carried out on specimens machined (in the tangential and radial directions) from prolongations of trial rotors and CRRs. An original approach was used for misalignment compensation, strain control and data recording, sensitivity analyses were finally performed on results
Experimental Investigation on the Effect of Shot Peening and Deep Rolling on the Fatigue Response of High Strength Fasteners
Full text linkShot-peening and deep rolling are mechanical surface treatments that are commonly applied to enhance the fatigue performances of components, owing to their capacity to generate compressive residual stresses and induce work hardening. However, literature is still poor of published data concerning the application of these treatments to high strength steels fasteners, although these represent a class of components among the most widespread. In the present work, the impact of deep rolling and shot-peening performed in the underhead radius of two set of fasteners made of 36NiCrMo and 42CrMoV for fatigue life enhancement has been investigated. The experimental tests consisted of six combinations of shot-peening and deep rolling, including the non-treated state. Two test campaigns have been sequentially carried out with dierent process parameters and treatment sequences. The results always showed a beneficial impact of the deep rolling on fatigue, especially for the 42CrMoV steel. Conversely, the eect of the shot-peening strongly depended on the selected set of parameters, alternatively leading to an improvement or a worsening of the fatigue life in relation to the level of induced surface roughness
Tribological properties of bolts depending on different screw coatings and lubrications: An experimental study
No full textThis paper is focused on the experimental determination of the frictional properties of bolts, following the ISO 16047 International Standard. The campaigns involved M14 X 2 8.8 class hexagonal head steel screw. Different Design of Experiment techniques were applied to investigate the effects of screw coating and lubrication, along with their interaction. The effect of lubrication was then investigated in further details, comparing two different lubricants and the outcomes of partial lubrication on the underhead or in the threads only. The results indicate that both surface coating and lubrication are highly significant. Regarding lubrication, a ceramic paste by Interflon proved to be highly effective at reducing friction, in particular if applied at the underhead rather than in the threads
Influence of the engagement ratio on the shear strength of an epoxy adhesive by push-out tests on pin-and-collar joints: Part I: Campaign at room temperature
No full textThis paper focuses on an epoxy adhesive (LOCTITE 9466), which is particularly suitable for applications involving different materials and where a clearance is present between the adherents. The investigated subject is concerned with the effect of the Engagement Ratio (ER, coupling length over coupling diameter) on the shear strength of LOCTITE 9466 at room temperature. Motivations arise from the increasing interest in epoxy-adhesive joints in lightweight structures and from the consequent need for design data. Decoupling tests have been performed on pin-and-collar samples manufactured according to current Standards. The height has been adjusted in order to explore a sufficiently wide ER range at four different levels. The results have been processed by the tools of the Analysis of Variance and of the Fisher test to investigate the significance or the not significance of ER on the joint shear strength. The final outcome was that ER significantly affects resistance at a very high confidence level. This result has then been refined by the tool of orthogonality, in order to allocate the differences among the four levels of ER. This further analysis has shown that the joint strength is significantly enhanced, when ER exceeds 1 and assumes values around 1.3 or higher
A user-friendly computational algorithm for the structural analysis of wrapping machine rotating rings
No full textWrapping machines usually consist of a two- or a four-column frame, supporting a huge rotating ring, connected to a prestretch unit with film coil carrier. Stiffness is a key point of packaging machines, since it is strictly related to the accuracy of the wrapping task. It depends on the stiffness of the frame, which can be achieved by the four-column architecture, and on the ring constraint system. As a consequence, the ring structures are usually highly statically indeterminate. Nowadays, there is an increasing demand for higher rotational speeds and more reduced operation times. Therefore, an accurate structural analysis of the ring, considering its actual loading and constraints is more and more important. The structural analysis of the rotating ring is treated by many references; however, such a statically indeterminate constraining makes this problem highly complicated. The goal of this paper consists in the development of a general and original computational algorithm for the structural analysis of rotating rings. The results are collected in a user-friendly way in terms of normalized internal loads, so that they can be of a great help even for not expert users. This model has been experimentally validated and easily applied to case studies and optimization tasks
Influence of the engagement ratio on the shear strength of an epoxy adhesive by push-out tests on pin-and-collar joints: Part II: Campaign at different temperature levels
No full textPrevious research led to the conclusion that the Engagement Ratio (i.e. the coupling length over the coupling diameter, ER) does not significantly affect the shear strength of an anaerobic adhesive (LOCTITE 648). Conversely, ER is effective on the response of an epoxy adhesive (LOCTITE 9466), with a beneficial effect for ER>1. The aforementioned campaigns have been performed at room temperature, whereas, the effect of ER combined to that of temperature is still unexplored. The subject of this paper consists in the experimental investigation of the impact of ER on the strength of LOCTITE 9466 at higher temperatures. Decoupling tests have been performed, considering three levels of temperature (40 °C, 60 °C and 80 °C). Pin-and-Collar samples have been prepared, considering four levels of ER. A fixture device has been designed, to prevent misalignments and to reduce heat dissipation during the pushing-out phase.
The statistical processing of the data led to the conclusion that ER retains its effectiveness up to the temperature of 40 °C with strength enhancement for ER beyond 1. Conversely, at the highest levels of temperature, a strength drop to approximately 44% occurs, and the effect of ER is no longer significant to compensate this decrease. Moreover, a highly significant negative interaction was detected between ER and temperature
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