bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pressures Distributions and Depth Stresses Developed in Concentrated Contacts Between Elements With Non-Gaussian Rough Surfaces
Authors: Urzică Ana C. , Bălan Mihaela Rodica D. , Creţu Spiridon S. 
Published: August 2013

The main step in a contact analysis between rough surfaces is the evaluation of the pressure distribution developed on the real contact area. The normal pressure distribution can be used further to predict subsurface stress, interfacial friction and surface wear. Only few real rough surfaces are Gaussian, most of that produced by manufacturing processes are non-Gaussian having an arbitrarily orientation. The definition of the roughness will include, in addition to the spatial characteristics, information about spectral characteristics of the surface, described with the use of autocorrelation function ACF.
Conjugate Gradient Method in conjunction with Discrete Convolution Fast Fourier Transform was refined and applied to solve the constrained system of equations that governs the pressure distribution between rough surfaces subjected to contact loading in elastic dry conditions. The paper reveals the role played by the spatial characteristics (standard deviation σ, skewness Sk, and kurtosis K) as well as by autocorrelation function on both the non-Hertzian pressure distribution on contact area and depth distribution of von Mises equivalent stress.
Improving Product Performance Through Manufacturing Knowledge Reuse in PLM
Authors: Urwin Esmond N. , Young Bob , Frazer Liam , Hunt David 
Published: August 2013

Successfully fulfilling customers’ needs with world class products whilst remaining competitive and profitable are a major driver for the aerospace industry. The 21st Century is placing ever increasing pressure upon manufacturers to deliver high complexity, technologically enabled products to instantaneously fulfill a desired purpose at the point of use. To meet such stringent criteria, companies must find ways to continuously improve, reduce waste and accelerate the product development process whilst innovating.
This paper presents a multiple case study approach of turbine blade manufacturing part families which has been used to further develop a manufacturing knowledge reuse method that is being developed in partnership with a high tech aerospace company for application within a PLM environment. This method is currently being explored within the company so as to accelerate the design-make process to enable earlier availability of, and easier access to, manufacturing knowledge, thus bringing about better product performance.
The contents of the paper presents a methodical approach to the study of a number of products in an effort to ascertain how the complex interrelationships between design knowledge and manufacturing knowledge change across part families and, consequently, how they affect a developed feature knowledge relationship structure (FKRS) that maps design, manufacture and inspection viewpoints of product knowledge. Utilizing the FKRS, a pragmatic way has been developed in which people-to-people knowledge can be captured and shared to facilitate a reduction in the associated lead-time for information and knowledge retrieval and reuse. For this to be more widely applicable to different types of turbine blade it is necessary to widen the scope of the research. Four case studies are presented showing the aspects that constitute a part family and how knowledge varies across the products being studied. The FKRS is applied to the captured manufacturing knowledge in an effort to prove that it can represent and model multi-context knowledge across part families.
The results have shown that the approach provides a basis for the representation of complex relationship viewpoints for product features and is valid for a number of manufacturing part families.
A Virtual Components Approach for Energy Consumption Modeling in the Machinery Sector
Authors: Leonesio Marco , Bianchi Giacomo , Borgia Stefano 
Published: August 2013

In recent years, energy consumption issues, boosted by environmental concerns, are becoming of paramount importance in the manufacturing field. In particular, machinery sector has been the theatre of several initiatives and projects aimed at an eco-efficient design and use of the machines. In this context, energy consumption modeling is considered a powerfull tool to foresee and optimize energy efficiency by design. On the other side, while each company has to develop numerical models of the internally designed machine elements, it has to be taken into account that machine productivity, eco-performance and cost are all strongly influenced by the employed commercial components (e.g. motors, sensors, controllers, transmissions, guide ways), that must be also be modeled but it is unrealistic to expect that the machinery builder develops by himself all required models.
In this paper, the industrial adoption of simulation tools and methodologies for energy consumption modeling is regarded as an application of the more general “Model Based Product Development” methodology. In particular, the development of “functional component models”, seen as Virtual Components (“VC”) to be assembled in the Virtual Machine, is suggested as the key to foster co-modeling activity involving suppliers. A proper business model is then proposed to guarantee the sustainability of the co-operation scenario.
Finally, the strategy concept is illustrated by some examples concerned with machine tool accessories and components.
An Elastic-Plastic Analysis of Profile Evolution in Cylindrical Roller Bearings
Authors: Creţu Spiridon S. , Benchea Marcelin I. 
Published: August 2013

The roller profile appears to be the key element to attain a longer rating life for both cylindrical and tapered roller bearings. A genuine elastic analysis is able to optimize the roller profile to obtain a stress distribution in the contact zones that provides enhanced operational reliability and greater insensitivity to misalignment. For traditional cylindrical-crowned roller profile design class I discontinuities exist at the intersection points of roller profile with the crowning radius as well as at the end chamfer. In an elastic analysis these discontinuities generate very sharp increases in pressure distribution diminishing the rating life of the bearing. In fact, these local increases in pressure distribution are able to overcome, locally, the yield limit and to induce both plastic deformations and residual stresses. After a certain number of cycles the material will shakedown elastically to a slightly modified roller profile and a stable state of compressive residual stresses. If were taken place, these changes have to be considered in the life evaluation.
An analysis model has been developed to simulate the nonlinear strain rate dependent deformation of rolling bearing steel stressed in the elastic-plastic domain.
The model is developed in the frame of the incremental theory of plasticity by using the von Mises yield criterion and Prandtl-Reuss equations. By considering an isotropic and non-linear kinematic hardening laws the model accounts for the cyclic hardening phenomena. For each new load increment new increments for the components of stress and strain tensors, but also increments of residual stresses, are computed for each point of the 3D mesh. Both the new contact geometry and residual stresses distributions, are further considered as initial values for the next loading cycle, the incremental technique being reiterated. The cyclic evaluation process of both the plastic strains and residual stresses is performed until the material shakedowns. For the case of cylindrical roller bearings with cylindrical-crowned roller profile, the role played by the crowning geometry on pressure distribution is pointed out for both the elastic analysis and elastic-plastic analysis. Further, the modified rating lives are evaluated using the methodology given in ISO 16281-2008.
New Development in High Efficiency Deep Grinding
Authors: Batako Andre D. L. , Kuzin Valery V. , Rowe Brian 
Published: August 2013

High Efficiency Deep Grinding (HEDG) has been known to secure high removal rates in grinding processes at high wheel speed, relatively large depth of cut and moderately high work speed. High removal rates in HEDG are associated with very efficient grinding and secure very low specific energy comparable to conventional cutting processes. Though there exist HEDG-enabled machine tools, the wide spread of HEDG has been very limited due to the requirement for the machine tool and process design to ensure workpiece surface integrity. HEDG is an aggressive machining process that requires an adequate selection of grinding parameters in order to be successful within a given machine tool and workpiece configuration.
This paper presents progress made in the development of a specialised HEDG machine. Results of HEDG processes obtained from the designed machine tool are presented to illustrate achievable high specific removal rates. Specific grinding energies are shown alongside with measured contact arc temperatures. An enhanced single-pole thermocouple technique was used to measure the actual contact temperatures in deep cutting. The performance of conventional wheels is depicted together with the performance of a CBN wheel obtained from actual industrial tests.
The Use of Adaptive PCA-Based Condition Monitoring Methods in Machining Processes
Authors: Grasso Marco , Colosimo Bianca Maria , Moroni Giovanni 
Published: August 2013

In different manufacturing applications the assessment of the health conditions of a machine tool, together with the quality and stability of the process, requires the capability of dealing with response variables described in terms of profile data. In the frame of in-process monitoring of sensor signals this is the case, for instance, of monitoring either series production of large lots of parts or machining processes characterized by cyclic signals, where both the condition of the machine components and the final quality of the worked piece may be correlated with the stability of repeating signal profiles in time. However, as far as real time data acquisition is concerned, and when measurements are performed with high sampling frequency, data are likely to be auto-correlated, and hence it is of fundamental importance to develop adaptive monitoring tools robust with respect to non-steady state conditions. The paper deals with the utilization of profile monitoring approaches for in-process monitoring of manufacturing operations and investigates their applicability to the problem of monitoring auto-correlated signals. In particular Principal Component Analysis (PCA) is applied in combination with an adaptive approach based on a moving time window for continuously revise the reference model is evaluated and discussed.
A real case study is used to test the performances of the method: the task is to detect tool chipping and breakage in end milling operations by means of real-time monitoring of cutting force signals. The evolution of tool wear imposes a trend in observed signals which leads to the need for an adaptive approach to properly isolate the breakage event from the slow pattern change due to wear mechanism.
Design of a Hand Exoskeleton for Space Extravehicular Activities
Authors: Mousavi Mohamad Mehdi , Appendino Silvia , Pescarmona Francesco , Battezzato Alessandro , Chen Fai Chen , Favetto Alain , Somà Aurelio 
Published: August 2013

Due to the bulk and stiffness of the astronauts’ glove, so called Extravehicular Activity (EVA) glove, many problems occur during their missions outside the spacecraft i.e. fatigue, dexterity reduction, decrease of possible EVA hours, etc. [1, 2]. To solve these problems a hand exoskeleton which can be embedded inside the astronauts’ glove has been proposed as a solution to help them to move their fingers more easily.
In this work all the steps that were taken towards the design of a preliminary version of the hand exoskeleton are explained in detail. The paper starts with a brief survey on related literature, followed by an analysis of three main research subjects for the design and realization of the hand exoskeleton: sensors, actuators and structure. In particular, different kinds of sensors and actuators are evaluated and advantages and disadvantages of each one are investigated. Then the main reasons to choose a specific type of sensor or actuator are described in detail. Regarding the structure, different possible solutions converging towards an optimal design for this application have been evaluated. Moreover, the use of some springs in the structure to simulate the stiffness of the EVA glove is proposed in order to be able to test the device in a condition similar to its final application. A brief description about the kinematic modeling and simulation of the structure in order to find the optimum location of the transmission cables and their tension forces is explained.
Usability Testing of Ultra High-Strength Steels
Authors: Heikkala Jouko A. , Väisänen Anu J. 
Published: August 2013

New ultra high strength (UHS) steels have been developed in order to get advantages in machine design and construction. Following benefits can be obtained for example:
- less material usage due to lighter constructions;
- better payload and less fuel consumption in vehicle industry;
- energy saving in material production.
A rough distinction of structural steels can be defined to ductile steels, with tensile strength less than 300 MPa, and high strength steels, up to 700 Mpa. A steel material can be defined as UHS steel when the tensile strength exceeds 700 MPa. Steels with yield strength of 1500 Mpa have been developed so far. UHS steels can also be divided into structural steels and wear resistant steels. With the tensile strength also the hardness increases and the tensile strain decreases. That causes several difficulties when the material is processed into products. Especially mechanical processing like bending, machining and shearing gets difficult as the material strength increases. That causes problems for the construction material users to find the proper manufacturing methods in production.
In Oulu University Production Technology Laboratory material processing tests have been performed during several years in co-operation with the local steel manufacturer. The usability tests comprise mainly of bending and machining tests. Shearing and welding tests have been made to a smaller extent. Also laser treatment has been used for local heat conditioning in order to improve the bending and shearing properties, but these techniques are not yet widely used in production.
The bending tests are carried out with standard bending tools and test steel plates with standard dimensions. The plate thickness varies depending on the test material. The target is to determine the reliable minimum bending radiuses whereby the plate can be bent without failure, from both sides and along the rolling direction and orthogonally to that. Also the springback angle is measured and the bent surfaces are evaluated according to several criteria. When necessary, also the mechanical testing of the formed material is carried out.
The machining tests are made mainly by drilling. Also some milling tests have been performed. Drilling is a convenient way of machining testing because a substantial amount of holes can be drilled in one test plate. The drilling power can be observed precisely by monitoring the spindle power. Also a variety of different tool types can be used, from uncoated HSS drills to boring tools with indexable inserts. The optimal machining parameters (feed and speed) will be defined according to maximum tool life and minimum machining costs.
An Innovation System for Building Manufacturing
Authors: Craveiro Flávio , Matos João Meneses de , Bártolo Helena , Bártolo Paulo 
Published: August 2013

Traditionally the construction sector is very conservative, risk averse and reluctant to adopt new technologies and ideas. The construction industry faces great challenges to develop more innovative and efficient solutions. In recent years, significant advances in technology and more sustainable urban environments has been creating numerous opportunities for innovation in automation. This paper proposes a new system based on extrusion-based technologies aiming at solving some limitations of current technologies to allow a more efficient building construction with organic forms and geometries, based on sustainable eco principles. This novel approach is described through a control deposition software.
Current modeling techniques focus only on capturing the geometric information and cannot satisfy the requirements from modeling the components made of multi-heterogeneous materials. There is a great deal of interest in tailoring structures so the functional requirements can vary with location.
The proposed functionally graded material deposition (FGM) system will allow a smooth variation of material properties to build up more efficient buildings regarding thermal, acoustic and structural conditions.
Coupling Engineering Knowledge With Product Design Knowledge by the Means of Multiple View Product Model
Authors: Rasoulifar Golnoosh , Prudhomme Guy , Brissaud Daniel 
Published: August 2013

Product design involves a multitude of actors who have complementary knowledge and responsibility about the product under development.
Coupling together their views-points, particularly these of product designers and engineering designers in the upstream phases of the design, has the objectives to make the collaboration easier and to improve the product from both of their expertises.
The Product/Process multi-view model is a collaborative tool which supports engineering designers during product development processes. It allows the structuring and tracing of relative knowledge of engineering designers on the product. We make the assumption that Product/Process multi-view model could also be used to create relationships with the product designer’s representation.
The paper deals with this product model and illustrates the possible connection between engineering knowledge and product design knowledge.
A Mass-Conserving Complementarity Formulation to Study Fluid Film Lubrication in the Presence of Cavitation for Non-Newtonian and Compressible Fluids
Authors: Bertocchi Luca , Giacopini Matteo , Strozzi Antonio , Fowell Mark T. , Dini Daniele 
Published: August 2013

A mass-conserving formulation of the Reynolds equation has been recently developed using the concept of complementarity [1]. The mathematical derivation of the Linear Complementarity Problem (LCP) implemented in the solver favoured in [1] overcomes the drawbacks previously associated with the use of such complementarity formulations for the solution of cavitation problems in which reformation of the liquid film occurs. In the present paper, the proposed methodology, already successfully applied to solve textured bearing and squeeze problems in the presence of cavitation in a one dimensional domain and for incompressible fluids [1], has been extend to a two dimensional domain and the fluid compressibility has been included in the formulation. The evolution of the cavitated region and the contact pressure distribution are studied for a number of different configurations.
Some of the results obtained with the proposed scheme are critically analysed and compared with the predictions obtained using alternative formulations (including full CFD calculations). The stability of the proposed algorithm and its flexibility in terms of the implementation of different compressibility laws is highlighted.
A Fast Deterministic Model to Study Adhesion in Rough Contacts
Authors: Medina Simon , Dini Daniele 
Published: August 2013

As two bodies come into contact, attractive forces occur wherever a gap exists between the two surfaces. The forces are significant at distances of atomic order but become negligible at much larger separations. Their effect is insignificant in most situations for which engineers wish to understand the state of the contact since the adhesive forces are usually much smaller than the net load applied and/or surface roughness results in non-contacting areas being far enough apart that the attractive force is negligible. There are, however, certain cases in which adhesion forces do contribute to the contact mechanics and must be accounted for in any valid analysis. Materials with low elastic modulus, such as rubber, may deform sufficiently around surface asperities such that the surface separation is small and adhesion is apparent.
A model for arbitrary geometry (with surface roughness) that includes adhesive forces is reported here. It is based upon the multi-level method of contact analysis developed by Venner and Lubrecht [1]. Adhesion has been implemented using the Lennard-Jones potential as applied to two parallel surfaces, adding the requirement of specific negative pressures for the separated surface nodes [2]. The model is then compared to theoretical and numerical analysis of smooth spherical contacts and to rough contacts of different scales and material properties.
A Methodology for the Connecting Rod Lubrication Optimization
Authors: Francisco Arthur , Lavie Thomas , Villechaise Bernard 
Published: August 2013

The numerical optimization of the connecting rod big-end lubrication involves several main steps.
The first, which can be considered as the most important one, is the identification of the main input factors and their varying range. In the same time, the meaningful resulting values have to be identified because the optimization will be performed on the basis of this choice.
The computing time for a TEHD solution prevents from performing a huge amount of calculi to draw the Pareto-Front of the solutions. Thus, the next step is the creation of a metamodel, based on polynomials, with a good predictability property and a low computing cost.
In the third step, a fast Multi Objective Optimization is performed on the metamodel. The Pareto-Front, which represents the best trade-offs of solutions, is identified: one can now easily choose the input parameters which will give a particular desired solution.
In the last step, the robustness of the solutions has to be checked: if a given solution is chosen, the corresponding input parameters have to enclose a minimal uncertainty gap to be realistic. Otherwise, this wanted solution will never be reached, because in a real-life problem, the parameter values are not deterministic.