scholarly journals Mechanics of Machines, Mechanisms and Materials

2020 ◽  
Author(s):  
E. Giannotti ◽  
C. Galletti

Abstract An attempt to focus problems encountered in teaching mechanics of machines to engineering students has stimulated the authors of this paper to develop specific software, lectures and laboratory activities with different emphases and relations between the teacher’s and students’ tasks. A multi-year study has been made to test if and how simulation, based on a hypermedia system, can be used in developing educational tools for this new courseware. As a result, new tools for learning mechanics of machines are proposed.


2004 ◽  
Vol 57 (2) ◽  
pp. B11-B11
Author(s):  
V Ramamurti, ◽  
RL Norton,

1968 ◽  
Vol 3 (3) ◽  
pp. 213-214
Author(s):  
J.M. Prentis

1990 ◽  
Vol 21 (3) ◽  
pp. 332-334
Author(s):  
M.J. Goodwin

2019 ◽  
Vol 9 (1) ◽  
pp. 68 ◽  
Author(s):  
Jacek Uziak ◽  
Venkata P. Kommula

The predominant educational methods in engineering education follow traditional classroom teaching, with some elements of tutorials and lab work. Although, there has been a growing tendency in recent years to introduce elements of active learning, and in particular problem-based (PBL) and project-based learning (PjBL). The paper reports on an attempt to use PBL in a topic on kinematics analysis of planar linkages, in a 3-credit course on Mechanics of Machines, offered in Year 3 of a 5-year BEng Mechanical Engineering programme. The aim of this study was to investigate the students’ response and perception to such a learning environment. A survey was administered to investigate students’ views on the application of problem-based learning in the course. The survey proves that the students responded well to the new approach en-joying activity (72%), trying hard (94%) feeling positive (68%), considering time spent to be beneficial (90%) and believing in instructor having best interest of the students in mind (74%). The response was also positive to interest generation and motivation towards the topic; 82% and 78% positive responses, respectively. The students were convinced about the learning new knowledge aspect of PBL. The majority declared learning more by gathering information themselves (66%) and especially more details on the topic in comparison to the traditional lecture/tutorial approach (72%).


Author(s):  
D. S. Blinov ◽  
I. S. Chunosov

There are a number of problems in mechanical engineering technology. One of them is related to the installation on the machine and the previous processing of thin-walled rings, which are widely used in mechanical engineering. Due to the low bending stiffness of thin-walled rings after processing there are a large magnitude of rigidity of the form (deviation from roundness). As production experience has shown, in the conditions of mass production, it is advisable to use fungal mandrels and adjustments to reduce shape errors. They allow for a small radial gap between the holes of the ring and the fungal cam to have extended contact rings with cams along the angular coordinate. However, there are no methods for calculating the parameters of contact interaction with cams, considering a number of factors, primarily the radial clearance. Hence, it is impossible to calculate more accurately the error of the form after processing. In this paper (it is supposed to be continued), based on methods for calculating flat rings of construction mechanics of machines, a method for determining the stress-strain state of a thin-walled state is proposed, considering the contact pressure. In this case, the semiangle of contact of the ring with the fungal cam and the shape of the contact pressure plot are determined. This allows you to calculate the stress state of the thin-walled ring and the shape error when processing more accurately in a fungal mandrel, as well as reasonably assign the dimensions of the mandrel parts. Due to the exceptionally large number of calculations in the calculations according to the proposed method, it can only be implemented using a computer program, which creates great difficulties in analyzing different source data. Therefore, it is planned to rework the completed developments into an engineering calculation method with graphs in dimensionless form.


Author(s):  
Massimo Sorli

The present report highlights the current and future role of techniques and methodologies of the Mechanics of Machines, both in the design of devices and systems, and in the university training courses. The underlying theme of the presentation lays in the interpretation of the physical phenomenon which oversees the operation of the machines. This is the foundation allowing to define an input-output interaction between the physical quantities operating on the machine. The cause-effect relation offers the possibility to determine a set of analytical relations for the prediction of the operation of the machine and to simulate theoretical and / or numerical trends in time or frequency domain of the significant mechanical quantities. It is evident the magnitude of the physical phenomena that arise in the operation of a machine, resulting in a broad variety of related Mechanics of Machines topics: from the contact between bodies analysis to tribological aspects, from body geometry to kinematics, from the rigid to deformable body dynamics, from the interaction between mechanical bodies to manmachine interaction, from the kinematic and dynamic behavior of a mechanical system to its interface with the actuators, sensing and control, just to name some of them. It should also be considered that the interpretation of the physical phenomenon of organs of machines has to be supported by significant experimental campaigns, specifically reproduced in laboratory, or related to data from real applications in the different application domains. The evolution of Mechanics of Machines proved in the years to be able to respond to these two interacting and converging questions: on the one hand the need to identify analytical relations, possibly not based on sole mappings of data, but rather on representative analytical relations of physical quantities, and on the other hand, the need, even at the university level, to conduct appropriate laboratory test campaigns related to the real field operation of the machine. With reference to the first objective, the need to determine algorithms, typically non-linear, and the consequent simulations setups, has resulted in the passage of the Machine Mechanics from a theoretical subject, to a subject with strong computational valences creating tools for the prediction of the behavior of devices and systems, in relation to their diagnosis and health state. The second objective has required the achievement of competence also in the field of the test rigs, of sensing and measuring / data acquisition systems. The paper deals with the identification and the presentation of the different areas related to Machine Mechanics, exposing in a matrix the enabling technologies on the one hand and the application domains to which they apply in the other hand. The enabling technologies traditionally belong to the topics of kinematics, statics, dynamics (linear and nonlinear), to the interactions with the environment (force fields, interactions with fluids) and between surfaces (lubrication), control, automation and system identification, as well as to the study and identification of vibratory phenomena, vibro-acoustic and tribological ones, mechatronics, fluid-structure interactions, monitoring, diagnostics and prognostics of mechanical systems, fluid automation and robotics, fluidics and microfluidics, to the implementation of pneumatic, hydraulic, electric and non-conventional technologies, to environmentally friendly and renewable energy systems. The application domains relate to the mechanical systems, such as driving and operating machinery, mechanical devices, mechanisms, transmissions and drives, automatic and robotic, vehicles on road, rail, fixed wing and rotorcrafts, transportation and lifting systems, systems for the production of energy, the biomechanical systems. A summary of the ongoing activities in the different research groups of the Italian Universities is then presented, from which you can also highlight the methodology of the studies addressed, strongly aimed at a unifying approach through the use of fundamental methods of theoretical applied and experimental mechanics, with attention to environmental and energy sustainability, and significantly connected on one side with the state of international research, and on the other with the industrial and manufacturing reality of the country. At the end of the paper sectors of Machine Mechanics that in the opinion of the writer need to be investigated further are discussed. Some technological challenges, such as prognostic models applied to servo systems in primary flight controls for aircraft applications, are outlined. The state of the art in that domain highlights the contribution to the innovation of processes and products, challenge that need to go back to the inputoutput interactions at the base-mechanics layer. Without those aspects it is impossible to be able to predict the evolution of degradation in the actuation systems, and to determine the remaining life of a mechanical device.


Author(s):  
G. H. Ryder ◽  
M. D. Bennett

2019 ◽  
Vol 23 (23) ◽  
pp. 27-35
Author(s):  
Mikhail Doudkin ◽  
Alina Kim ◽  
Murat Sakimov

Abstract The article is devoted to solving the fundamental and applied problem of nonlinear structural mechanics of machines by introducing into the drum two additional stop cylinders with supporting rollers at the end and adjustable length, providing a given elliptical or circular shape of a flexible shell with a smoothly variable geometry in the area of its contact with compacted pavement material. Compaction of soil, gravel and asphalt concrete in the sphere of road is not only an integral part of the technological process of the roadbed, road foundation and surface construction, but it is actually the main operation to ensure their strength, stability and durability. The quality, cost and speed of road construction, the possibility of using fundamentally new technologies, structures and materials is largely determined by the availability of modern road machinery.


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