Jánes Landre

Tribological behaviour when face milling AISI 4140 steel with minimum quantity fluid application

Purpose – The purpose of this paper is to evaluate the performance of cutting fluid applied by minimum quantity technique when milling AISI 4140 steel with TiAlN coated cemented carbide inserts.Design/methodology/approach – The vegetable oil based cutting fluid evaluated was applied through a nozzle at the centre of the tool holder under vaporized conditions with a flow rate between 0 (dry cutting) and 200 ml/h, at 50 ml/h increments. Tool wear (based on maximum flank wear, VBmax), surface roughness parameters (Ra and Rt) and burr formation (length of burr, h) were recorded and evaluated. Scanning electron microscope images and energy dispersive X‐ray analysis of the worn tools show adhesion as the dominant wear mechanism.Findings – Encouraging tool performance was recorded when milling AISI 4140 steel due to improved lubrication and cooling at the cutting interfaces. Increase in cutting fluid flow rate improves tool life with gradual reduction of the surface roughness parameters and negligible influence ...

Design of mechatronic system to inspect power transmission lines and towers

The inspection of power transmission line is currently carried out by a group of technicians that use gondolas, off-road vehicles or helicopters and airplanes to perform the task. Unfortunately, in most cases defects are rarely recognized in the early stages because of inadequate inspection. Based on this difficulty and taking into account that a new inspection system should attend requirements such as safety, cost, accuracy, autonomy, and the ability of negotiating obstacles along its path, we developed a mechatronic feasibility study of six different proposals. This paper presents the design concepts and the mechanisms used. Outlooks on the subject are also addressed. The design methodologies and tools applied during the feasibility study are underlined. The feasibility study was promising and the project is in progress

A New Vehicle 3D Model with 7 Degrees of Freedom for Vehicle Dynamical Response Studies

Last decades offered significant technologic achievements regarding vehicle power, speed, and complexity. The full understanding of vehicle characteristics and their influence on vehicle response behavior during maneuvers became essential for vehicle quality as well as passenger safeness and comfort. On the other hand, due to high competitive and globalized economy, automotive industries underline the necessity of reducing costs and time-to-market while improving the quality of their products. A critical part in the vehicle design process that usually requires specialist knowledge and time consuming work is suspension adjustment. In this scenario an obvious alternative for evaluating dynamically new vehicle projects is the use of mathematical models and simulation tools in order to reduce the need of vehicle prototypes and experimental tests. There are several commercial software packages developed to support the “road-to-lab-to-math”. It is possible to find on market several examples of these packages, such as ADAMS (MSC - USA), AutoSim (Mechanical Simulation Corp. - USA), DynaFlex (Waterloo - Canada), MECANO (Samtech - Belgium), RecurDym (Function Bay Inc. - Korea) and many others. Unfortunately most of these software packages are not flexible enough to satisfy the engineers’ needs and still require a strong knowledge about vehicle dynamics. Due to this, Engineering Schools are turning their attention to the development of simulation tools that are able to provide a link between academy knowledge and industry necessities, preparing engineering students to become automotive engineers. This paper presents a new 3D 7-DOF vehicle model that takes into account the anti-roll bar when it comes to modeling the vehicle suspension. We applied the d’Alembert approach to obtain the model equations. In order to implement the model, we used the MatLab software and its ode45 function for solving the differential equation system. The model developed succeeded in providing time responses, which are coherent with the ones offered by literature. This model is also in accordance with assumptions made by engineers who are involved with vehicle tests in the automotive industry. Regarding the analysis of the suspension system interaction - with and without the anti-roll bar and its influence in the body response - it is positively in accordance with the hypothesis raised. A new version of this software is being designed to add optimization and sensitive analysis tools.

Tooth displacement in shortened dental arches: A three-dimensional finite element study

STATEMENT OF PROBLEM Some patients may opt for a prosthetic rehabilitation without replacing all missing teeth, finishing treatment with a reduced dental arch. This choice may be due to biologic reasons or financial restrictions. It is unclear if a reduced dental arch functions as well as a complete dental arch. PURPOSE The purpose of this study was to analyze whether shortened dental arches could result in tooth displacement. MATERIAL AND METHODS Four different 3-dimensional maxillary and mandibular arches with different levels of arch length reduction were created. In all models, anatomic structures that represent the temporomandibular joint, cortical and cancellous bone, enamel, dentin, and periodontal ligament were modeled. Mechanical properties were attributed to each anatomic component, and a total occlusal load of 100 N on masseter, temporal, and medial pterygoid muscles was simulated for each model. The MSC. Patran software was used for the preprocessing and postprocessing of the biomechanical analysis of the models. One complete dental arch was used as the control. RESULTS The simulations showed that shortened dental arches presented greater tooth displacements than those found in a complete dental arch. The changes in mandibular tooth position were greater than those observed in the maxillary arches. In finite element models 1 and 2, the largest maxillary displacements were found for posterior teeth. CONCLUSIONS Decreasing numbers of occlusal units resulted in increasing amounts of displacements of the remaining teeth, which may compromise dental stability in patients with shortened dental arches.

An Integrated Educational Tool for Vehicle Dynamical Response Studies

The automotive industry is today highly competitive, globalized, and characterized by continuous efforts to improve its products quality and reduce the products costs and time-to-market. Solutions to this paradox do not permit trial-and-error, necessitating instead the adoption of a more complex developmental paradigm. In this scenario the term “road-to-lab-to-math” describes the effort to reduce the quantity of on-road testing and replaces it with laboratory testing components and subsystems, and to so efficiently by using complex mathematical models that make evaluation of inuse conditions more precise and realistic. Due to this, Engineering Schools are turning attention to the use of simulation tools in the undergraduate courses. There are several commercial software packages developed to support the “road-to-lab-to-math”. If we focus on virtual prototyping tools applied to vehicle dynamic responses, all of the commercial simulation packages implement multi-body models composed of both rigid and flexible parts. It is possible to find on market several examples of these packages, such as ADAMS (MSC - USA), AutoSim (Mechanical Simulation Corp. - USA), DynaFlex (Waterloo - Canada), MECANO (Samtech - Belgium), RecurDym (Function Bay Inc. - Korea) and many others. Frequently these packages use a multi-body system approach to obtain the vehicle dynamic responses during maneuvers. Most of the commercial software packages are prohibitively expensive for mechanical engineering schools and students to buy them. In addition to this, usually these software packages do not have tools to permit more complex analysis, using for example Finite Element Modeling (FEM) and Operating Deflection Shapes (ODS). This forces the users to acquire other software packages to complete the dynamical response study. This paper presents the development and implementation in MatLab of an educational tool developed to help mechanical engineering students to understand and visualize the vehicle chassis vibration under given operating conditions (for example, during ride analysis). It is constituted of two integrated parts: the first one, a multi-body-based handling, ride, and comfort analysis toolbox called as MDV, and the second one, a CAD, ODS, and FEM analysis toolbox called as ADES.

Machining Dynamics in Turning Processes

The dynamic stability of a machine tool in the turning process depends essentially on the compliance of the lathe turning structure, as well as on the properties of the cutting process [1]. However, the design of the machine tool, the material(s) employed for its manufacture and their mechanical properties are extremely important for the dynamic behaviour of the machining system (comprising the entire lathe and the work material) [1-13]. Theoretical details of dynamic stability and how to quantify, measure and monitor them as well as other phenomena such as chatter (self-excited vibration) and forced vibration have been covered in previous chapters. This chapter will, therefore, focus on the illustration and the discussion of practical details regarding the turning process. The influence of the input on the output parameters will be evaluated with regards to the dynamic stability in a turning process. The main input parameters affecting the machining system vibration are: work material, work material geometry, tool material, tool geometry, lathe rigidity, cutting conditions (cutting speed, vc, feed rate, f and depth of cut, doc) and tool wear. The behaviour of the machining system during vibration is a major output parameter.