1,721,067 research outputs found
Example of loads and stresses acting on the rear suspension
No full textIn this chapter is presented an example (case study) of calculations and definitions of loads and stresses obtained by applying the formulae discussed in the Chaps. 1 and 2. The results are obtained using a calc sheet in order to solve the recursive problem caused by the implicit function of the equilibrium equation associated to the rear suspension and in order to produce the diagrams of loads and stresses. Loads and stresses have been calculated depending on some fixed and variable parameters while results are presented in tables and diagrams so that it is possible to highlight their trend and their maximum values
The front suspension
No full textIn this chapter, the authors introduce the telehydraulic fork, which has become, across the years, the most common kind of front suspension for motorbikes. In chronological order, some noteworthy patents are presented, which help the reader following the main steps of the technical evolution which gave front motorbike suspensions their current shape. Then, the behaviour of some key structural elements of the fork is examined, under the assumption that the fork is subject to a bending moment acting on the front wheel mid-plane. Such a noteworthy loading condition is frequently encountered during the life cycle of a motorbike: consider, for instance, an emergency braking manoeuvre. Tests which simulate the effect of a hard braking on the fork are also part of the product validation programmes of the main motorbike producers. It is illustrated an analytical model useful for calculating the stress state of the fork legs under said loading condition. Such a model takes into account some architectural configurations as well as some characteristic geometrical parameters of the fork and of the motorbike. The model was validated referring to some production forks, both by finite element analyses and by experimental tests on the road. In the case of forks equipped with a single brake disc, the load unevenness between the legs during braking is analysed, and some strategies aimed at reducing such loading unbalance are suggested. The model presented herein could be helpful for designers who are developing new fork models, because it allows foreseeing critical issues due to legs dimensioning since the early phase of product development, when FEA techniques may be difficult to implement
The rear suspension equilibrium
No full textThis chapter aims at defining the equations that govern the rear suspension in term of the overall equilibrium and loads applied for different conditions of the motorbike motion. The formulae are useful for designing a rear suspension made by a unique arm which connects the frame pin with the wheel axle. The equations are non-linear and implicit so that they can be solved by recursive methods applicable in a calc sheet. The mathematical models can be applied to different types of rear suspension but they are developed for the peculiar case of those equipped with an articulated mechanism which leads to a progressive stiffness of a single arm rear suspension
Motorbike equilibrium
No full textThis chapter aims at defining the equations that govern the motorbike equilibrium and are useful for designing the front and the rear suspensions. Such equations are, in some case, non-linear and implicit so that they can be solved by recursive methods applied and presented in the Chap. 3 of this book. The mathematical models can be applied to different types of motorbike but they are developed for the peculiar case of those that adopt a single braking disk installed on front suspension and with a unique arm for the rear suspension
Vibration loosening analysis and simulation of preloaded threaded fasteners
No full textLoosening is widely regarded as one of the main failure modes of threaded fasteners, as confirmed by a survey of 100 automobile dealers in the Detroit Metropolitan area, which revealed how an average of 23% of the service issues were (still in 1988) related to loosening of fasteners. Indeed, some automakers reported peaks of service issues related to loose fasteners close to 40%, the greatest areas of concern being rocker arms, the oil pan, engine mounts and the body in general. Over the years, the literature consistently reported several different failure scenarios of threaded connections whose root cause can be traced to loosening. The present chapter aims at giving a basic understanding of the phenomenon of bolt self-loosening, starting with a definition of self-loosening and, more specifically, vibrational loosening
Mechanical characterization of parts fabricated by additive manufacturing
Full text linkThe explosion in the numbers of industrial applications making use of additive manufacturing (AM) techniques requires the use of reliable experimental data and appropriate design methods in order to ensure the adequate performance and safety of newly designed AM components. This Special Issue represents a collection of both experimental end numerical studies, covering the two realms of metallic and polymeric materials. The Special Issue is completed by papers focused on design and optimization problems, and on repair as well as on cost issues related to the production of AM components, which provide useful guidelines for design engineers and researchers
Special issue on new trends in mechanical design and product development
Full text linkThis special issue is devoted to a special selection of the best papers presented at the Mechanics and Materials in Design International Conference (M2D 2019) held in Bologna (Italy) in 2019. The M2D 2019 was the eighth international meeting of the M2D series, gathering hundreds of scientists and engineers interested in the fields of mechanics, engineering design, advanced materials, energy harvesting, reliability, quality, and safety engineering. It was held between 4th and 6th of September 2019. Almost 160 contributions in the fields of Mechanics, Materials and Design at varied length scales, as well as Biomechanics and Experimental and Computational Mechanics applied to Mechanical, Aeronautical, Automotive, Biomedical, Environmental, and Nuclear Engineering were submitted to the Scientific board. The best 100 of those papers were selected for an oral presentation with the goal to enable engineers, researchers and scientists to exchange ideas on the following and other derivative topics
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
- …
