bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamic Mechanical Characterization of CF/GF Hybrid Reinforced Polymeric Composite Structures
Authors: Luca Motoc Dana
Published: August 2013

The importance of dynamic mechanical analysis (DMA) as a research tool in the study of polymeric composite structures behavior has been already demonstrated in the literature. Many papers were approaching the relaxation phenomenon within the polymer based composite structures and thereby their behavior under various conditions of stress and temperature. Supplementary, the effect of fillers geometry, orientation and volume fraction have been extensively approached while considering the micromechanical level and their role in the mechanical properties were suitable stated. Hybridization of two different fillers has proven to an effective method in material design allowing their developers to tailor their properties according to the application driven imposed requirements.

The herein paper attempts to present a comparative study centered on the development and characterization of a hybrid polymeric composite structures made up from different combinations of carbon and glass fibers by evaluating their dynamic mechanical properties.

The samples were measured using the Dynamic Mechanical Analyzer (DMA) from NETZSCH-DMA 242 C, in the 3-point bending mode, nitrogen atmosphere, at a scanning rate of 3 K/min from −40 to 180° C with a fixed frequency of 1 Hz. Storage and loss modulus, loss tangent were recorded as function of temperature both on longitudinal and transverse direction of the unidirectional carbon fibers, in two consecutive heating cycles. A reference sample was set up to aid the comparison analysis, made entire from one filler type.

The effect of the fillers type, fillers relative volume fraction and temperature on the storage and loss moduli will be deeply investigated.
Optimality Criteria for Measurement Poses Selection in Calibration of Robot Stiffness Parameters
Authors: Wu Yier , Klimchik Alexandr , Pashkevich Anatol , Caro Stéphane , Furet Benoît
Published: August 2013

The paper focuses on the accuracy improvement of industrial robots by means of elasto-static parameters calibration. It proposes a new optimality criterion for measurement poses selection in calibration of robot stiffness parameters. This criterion is based on the concept of the manipulator test pose that is defined by the user via the joint angles and the external force. The proposed approach essentially differs from the traditional ones and ensures the best compliance error compensation for the test configuration. The advantages of this approach and its suitability for practical applications are illustrated by numerical examples, which deal with calibration of elasto-static parameters of planar manipulator with rigid links and compliant actuated joints.
Kinematic Effects of Gimbal Joints on a 3URU Parallel Manipulator
Authors: Baghi Sina , Razban Fariborz , Osgouie Kambiz G.
Published: August 2013

Gimbal transmissions are non-linear direct transmissions and can be used in robotic arms replacing the traditional revolute joints. They offer potential advantages for critical cases such as joint space and task space singularities or where a different mechanical advantage is needed compared to what traditional revolute joints provide. This can be obtained by properly adjusting the different parameters of Gimbal joints used in different joints of the manipulator (such as their offset angle and/or chamfer angle). In this paper the concept of Gimbal mechanism as a joint is investigated. Then, as an example, Gimbal joints are used to replace the basic revolute joints of a 3-UPU parallel manipulator and actuator velocities are obtained for a task space trajectory. The outcomes for a manipulator with traditional revolute joints and with Gimbal equipped joints are compared. Then the workspace and dexterity analyses are done on both manipulators.
New Mechanical Generators of Schoenflies Motion Implementing Bennett Linkages
Authors: Lee Chung-Ching , Hervé Jacques M.
Published: August 2013

Based on the Bennett 4R chain, we construct a rotating loop by fixing one R axis to the frame and the fixed R becomes a coaxial double R pair. The R pair opposite to the fixed double R is replaced by a spherical S pair which can be equivalent to a (RRR) open chain with non-coplanar intersecting axes. In the (RRR) sub-chain, we choose special axes and derive R|- R|(R(RRR)R chain moving with 2 DoFs. That moving R becomes a coaxial double R with the addition of another rigid body and the obtained chain with hybrid topology generates a 3-dof motion, which is mathematically modeled by a 3D submanifold of a 4D group of X motions. Because of the product closure in an X-motion group, adding an H pair with any pitch and an axis parallel to the fixed R axis leads to a mechanical generator of a 4D X-motion group. Then, parallel arrangement of two generators of the same X motion gives a new parallel generator of X motion, which can be actuated by four fixed R pairs; the two Hs must have distinct pitches. A special design with four collinear actuated axes is revealed too.
Cutting Force and EMG Recordings for Ergonomics Assessment of Meat Cutting Tasks: Influence of the Workbench Height and the Cutting Direction on Muscle Activation Levels
Authors: Pontonnier Charles , Dumont Georges , de Zee Mark , Samani Afshin , Madeleine Pascal
Published: August 2013

Repetitive arm movement and force exertion are common in meat cutting tasks and often lead to musculosketal disorders. In this study, the effects of the workbench height and the cutting direction on the levels of muscular activation of the upper extremity during meat cutting tasks were investigated. Seven subjects performed 4 trials of 20s each at the 4 different heights (0 cm, −10 cm, −20 cm and −30 cm below the elbow height), alternating two cutting directions. Activation levels of upper extremity muscles (biceps brachii, triceps long head, deltoideus anterior, deltoideus medialis and upper trapezius) and cutting forces were recorded synchronously. Then the trends of the normalized activations with regard to the workplace design parameters (table height and cutting direction) were computed. Results showed that the optimal configuration is a partially related to the task, whereas motor control strategies have also an influence on it. The present results provide new key information about the effects of workbench heights during a repetitive meat cutting task and a complete assessment protocol to analyse workstation design parameters influence on muscles activation levels.
Experimental Characterization of a Permanent Magnet Magnetorheological Clutch for Automotive Applications
Authors: Bucchi Francesco , Forte Paola , Frendo Francesco
Published: August 2013

In this work a magnetorheological clutch prototype with a permanent magnet is presented and the torque transmitted in several operating configurations is obtained by a specifically designed test bench. The clutch prototype was designed in order to have the possibility to disengage the vacuum pump which operates the power brake in diesel engines continuously. Torque transmission and size specifications were suggested by the specific application. A permanent magnet was used in order to obtain a fail-safe operation and particular attention was focused on materials selection in order to maximize torque transmission in the engaged mode and to minimize power consumption when the clutch is disengaged.

Tests were carried out on the test bench, in which electric motors apply the driving and braking torques to the primary and secondary shaft of the clutch; the transmitted torque was measured by a torque-meter at several rotational speeds. Experimental results are discussed in the paper with reference to classical literature models. The experimental tests gave also useful indications on possible improvements in the clutch design, especially regarding the seals, which have to prevent leakages at the working fluid pressure and to keep the friction losses low.
Tools Interoperability in Engineering Design Using Model-Based Engineering
Authors: Iraqi Houssaini Mehdi , Kleiner Mathias , Roucoules Lionel
Published: August 2013

Computer-aided engineering is widely used in various areas including manufacturing, requirement planning and product design. These specific CAE tools, here called expert tools, manipulate large amounts of data. Some of those data also need to be processed by other expert tools to allow a flexible collaboration between various experts. This article proposes an approach to exchange data of various formats manipulated by different expert tools through model-based technologies. The presented approach is validated by its implementation on an academic use case involving commercial industrial tools.
Mechanical Behavior and Damage of Tridimensional Multilayered Ceramics-Tungsten Power Electronic Substrates
Authors: Robert Charlotte , Pommier Sylvie , Lefebvre Stephane , Ortali Marion , Massiot Michel
Published: August 2013

Since few years a 3D electric lines is developed. But new applications will be to expose this circuit to high variation of temperature and use them for electronic power. Circuits lines are made of tungsten and insulation in alumina. These materials have different behavior. That difference implies mechanics stress and stress singularities. Some stress concentration can fracture materials or interface between them. Alumina is a brittle material. We need to know his fracture behavior. A statistic model is already used: Weibull model. The idea is to break about hundred samples and to related the probabilities to break of alumina used in the circuit versus stress.
Design of a New Mechanical Variable Valve Actuation System for Motorcycle Engines
Authors: Abagnale Carmelina , Migliaccio Mariano , Pennacchia Ottavio
Published: August 2013

This paper deals with design and manufacturing of a mechanical variable valve actuation (VVA) system, developed as part of a MUR financed research project concerning the realization of a high performance motorcycle engine, through a partnership of Moto Morini (Bologna), Dell’Orto (Milano), Istituto Motori - CNR (Napoli) and DiME (Department of Mechanical Engineering and Energetics) – University of Napoli Federico II.

After a synthetic description of the main variable valve actuation methods currently employed, the paper presents the results of our mechanical VVA system, consisting of three main elements: cam, main rocker arm with fixed fulcrum and secondary rocker arm with mobile fulcrum. This VVA system (system 1) enables valve lift variation by a simple translation of one of the three elements (the intermediate one). The study has been conducted implementing a numerical procedure specifically designed to determine cam profile and kinematic and dynamic characteristics of the whole system, starting from the following input data: rocker arm geometry, relative positions and inertial data of elements, spring stiffness and preloading, camshaft speed and valve lift law. The model has been validated against the conventional timing system using kinematic simulations. Results of the numerical procedure verify the validity of the VVA system, capable of a valve lift variation, with a limited acceleration. Starting from the numerical results, we have developed a new mechanical variable valve actuation system (system 2): it consists of the same three elements used previously, but they are connected in a different way. The newer system enables more general lift profile distributions with a similar geometric complexity. The activity has been extended to research for a new solution (always a mechanical system), capable to allow inlet valves complete closing and timing and duration variation (system 3).

This paper reports results reachable with the simplest system 1, that gives better perspectives of use for a new two-wheel vehicle engine.
Assistance to Automatic Digitizing System Selection for 3D Part Inspection
Authors: Audfray Nicolas , Mehdi-Souzani Charyar , Lartigue Claire
Published: August 2013

To perform 3D inspection, the most common digitizing system is a coordinate measuring machine (CMM) equipped with a touch trigger probe. Because of their large time consuming, a large number of industrial digitizing systems presenting different characteristics have recently emerged, but collected data quality strongly depends on the sensor technology combined with the associated displacement system. The works presented here focus on a novel approach that help users to select the most appropriate digitizing system in regard of the specification to be verified. This selection is performed in two steps: an ability selection that removes non convenient systems and a performance selection to select the system that provides sufficient data quality in the minimum time. This quality can be noise, trueness, density, depending on the specification to be verified. To store all necessary information, databases that contain intrinsic and qualified information have been developed. An example with GPS specifications is treated.
Robotic Rehabilitation Devices of Human Extremities: Design Concepts and Functional Particularities
Authors: Sargsyan Suren , Arakelian Vigen , Briot Sébastien
Published: August 2013

All over the world, several dozen million people suffer from the effects of post-polio, multiple sclerosis, spinal cord injury, cerebral palsy, etc. and could benefit from the advances in robotic devices for rehabilitation. Thus, for modern society, an important and vital problem of designing systems for rehabilitation of human physical working ability appears. The temporary or permanent loss of human motor functions can be compensated by means of various rehabilitation devices. They can be simple mechanical systems for orthoses, which duplicate the functions of human extremities supplying with rigidity and bearing capacity or more complex mechatronic rehabilitation devices with higher level of control. We attempt to cover all of the major developments in these areas, focusing particularly on the development of the different concepts and their functional characteristics. The robotic devices with several structures are classified, taking into account the actuation systems, the neuromuscular stimulations, and the structural schemes. It is showed that the problems concerning the design of rehabilitation devices are complex and involve many questions in the sphere of biomedicine, mechanics, robot technology, electromechanics and optimal control. This paper provides a design overview of hardware, actuation, sensory, and control systems for most of the devices that have been described in the literature, and it ends with a discussion of the major advances that have been made and should be yet overcome.
A Sensitivity Study on a Hybrid FE/MB Human Middle Ear Model
Authors: Volandri Gaia , Di Puccio Francesca , Forte Paola
Published: August 2013

The human middle ear includes the tympanic membrane and the ossicular chain. The finite element method is capable of representing the complex geometry and the material orthotropy of the tympanic membrane. On the contrary, the ossicles can be considered as rigid bodies and a multi-body approach can be adopted. In the present study a multi-body model of the ossicular chain and other structures (joints, ligaments and muscle tendons) of the middle ear was developed and combined with a finite element model of the tympanic membrane through a feedback control strategy. An optimization procedure was used to calibrate unspecified or uncertain parameters with the aim of reproducing ascertained experimental literature data. The sensitivity of the calibrated models to both tympanic membrane and ossicular chain parameters was investigated. Material, geometrical and inertial parameters were considered, in particular those whose values were most widespread in the literature.
A Functional Approach to Optimal Dimensioning of Automotive Transmission Shafts
Authors: Lanzotti Antonio , Patalano Stanislao , Rufrano Vito
Published: August 2013

The paper deals with a functional approach to optimal dimensioning of automotive transmission shafts. In particular, the paper summarizes the results of a research activity developed on automotive transmission shafts to reduce the unpleasant movement of the transmission lever known as “shift lever movement”. The design problem was faced by focusing the axial clearances of the wheels assembled on the transmission shaft.

First, the functional approach to optimal dimensioning proceeds from the study of different working conditions of the automotive manual transmission and focuses on corresponding geometrical constraints and design parameters. Then, it uses simplified schemes, each of them related to a different working condition, to set a series of functional dimensioning loops for the transmission shaft. Subsequently, the approach introduces an appropriate index to evaluate the Information Content for each dimensioning scheme and it addresses the optimal dimensioning scheme, related to the minimization of the Information Content. After this, the approach foresees worst-case to check the axial clearances of the wheels assembled on the shaft. In a such way the effect of the dimensioning are directly evaluated in terms of performances of the transmission. In fact, the reduction of axial clearances for the wheels assembled on the shaft causes a direct reduction of the “shift lever movement”.

The functional approach to optimal dimensioning is applied to an automotive transmission set and the proposed dimensioning schema of the shaft is compared with different dimensioning schemes including one currently used in an international automotive company. A final discussion of the results, in terms of reduction of axial clearances of the parts assembled on the shaft, is provided.
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.
Prognosis of Component Degradation Under Uncertainty: A Method for Early Stage Design of a Complex Engineering System
Authors: Yu Bo Yang , Honda Tomonori , Zak Gina M. , Mitsos Alexander , Lienhard John , Mistry Karan , Zubair Syed , Sharqawy Mostafa H. , Antar Mohamed , Yang Maria C.
Published: August 2013

This paper proposes a method that dynamically improves a statistical model of system degradation by incorporating uncertainty. The method is illustrated by a case example of fouling, or degradation, in a heat exchanger in a cogeneration desalination plant. The goal of the proposed method is to select the best model from several representative condenser fouling models including linear, falling rate, and asymptotic fouling, and to validate and improve model parameters over the duration of operation. Maximum likelihood estimation (MLE) was applied to obtain a stochastic distribution of condenser fouling. Akaike’s Information Criterion (AIC) and the Bayesian Information Criterion (BIC) were then computed at time intervals to assess the accuracy of the MLE results. The degradation model was further evaluated by estimating future prognoses and then cross-validating with real world fouling data. The results show the accuracy of a prognosis can be improved substantially by continuously updating fouling model parameters. The proposed method is a step toward facilitating prognosis of engineering systems in the early design stages by improving the prediction of future component degradation.
Towards Building a Multiscale Mechanical Model for the Prediction of Acute Subdural Hematomas
Authors: Nierenberger Mathieu , George Daniel , Baumgartner Daniel , Rémond Yves , Ahzi Saïd , Wolfram Renée , Kahn Jean-Luc , Abdel Rahman Rania
Published: August 2013

Acute subdural hematoma (ASDH) is a potentially devastating, yet curable, extra axial fluid collection within the subdural space situated between the skull and the cortex. It is often due to rupture of bridging veins crossing this subdural space, caused by the brain-skull relative motion. To be able to predict ASDH, a numerical model reflecting the mechanical properties of vascular walls is attractive. With this in mind, a suitable approach consists in modeling the material microstructure at different scales. In a former work [1, 2], R. Abdel Rahman studied the mechanical properties of the bridging veins – superior sagittal sinus junction when a human head is submitted to shock. This work showed the apparition of ASDH over a given value of head rotational acceleration. But lacks in the knowledge of microstructure and of the constituents mechanical properties were put forward in understanding the relations between material mechanical behavior and the apparition of ASDH. Therefore we chose to adopt a multiscale approach to model ASDH apparition. In the current work, several experimental observations have been set up to obtain a sufficient knowledge of the vein wall microstructure which was imprecisely documented to date. Stained thin slices of human brain were observed by optical microscopy. In addition, microtomography was used to assess the collagen fibers orientations. These observations allowed the identification of the different scales needed for modeling the microstructure. Many authors [3–6] deal with the mechanical behavior of vascular walls and of their various constituents but none of them consider multiple scales for modeling [7]. The next step of this work consists in improving the predictive capabilities of the existing model by going down the scales and taking microstructure into account. This methodology enabled the introduction of only physical parameters into the model, which is essential for future predictive capabilities. Finally, a failure criterion for the bridging veins taking into account the different scales has been created and is still being improved. It allows the evaluation of specific disease influence like collagen damage due to physiology. Besides it provides a prediction tool for ASDH useable for optimization of various shock absorbers.
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.
A Numerical Approach for the Evaluation of Residual Stresses in the Automated Tape Placement Process
Authors: Poulhaon Fabien , Ghnatios Chady , Bognet Brice , Barasinski Anais , Leygue Adrien , Chinesta Francisco
Published: August 2013

Automated tape placement (ATP) is a process recently developed for the production of large parts (plates, shells) made of thermoplastic composites. In ATP a tape is placed on the previous ply and welded by a local heating and pressure to build up a laminated structure. The numerical modeling of such a process is a challenging issue since the thermal history of each ply is different, depending on its position within the structure. The evaluation of residual stresses is particularly important for determining the deformed shape of the piece at the end of the process. A numerical model based on the Proper Generalized Decomposition is proposed. The solution of the 3D thermal problem is performed first. Thermal contact resistances are in particular introduced in order to model the imperfect heat conduction at the interface of two neighboring plies. The computed temperature field is then introduced in the mechanical model considering a thermo-elastic behavior for the material. An incremental approach is therefore used on a control volume in order to compute the evolution of the stresses within the laminated structure during the process.
Online Monitoring of Drilling-Induced Delamination of Composite Materials by Acoustic Emission
Authors: Karimi Navid Zarif , Heidary Hossein , Najafabadi Mehdi Ahmadi , Kianfar Parnian , Minak Giangiacomo , Zucchelli Andrea
Published: August 2013

Drilling composite materials is one of the primary processes of manufacturing industrial structures. The ultimate goal towards on-line monitoring of composites drilling is in order to produce damage free high quality drilled holes. In the present investigation, the acoustic emission (AE) technique was applied for monitoring the drilling-induced delamination. Delamination is major damage mechanisms in glass fiber reinforced plastic (GFRP) laminates correlated with the thrust force during drilling process. By feature extraction of AE time domain, root mean square (RMS) is selected as the best parameter to monitor thrust force variations. The experimental results show that AE is very sensitive to the response of the drilling conditions.
Measurement and Comparison of Force Effort During Friction Stir Welding in a Parallel Kinematic 5-Axis Milling Machine
Authors: Manogaran Arun Prasath , Racineux Guillaume , Hascoet Jean-Yves
Published: August 2013

Friction stir welding (FSW) is so quite promising that leads it to one of the preferred joining process for a wide range of applications especially for Aluminum. FSW machines are very expensive. The objective is to develop a simple and low cost technique to measure and control the force during FSW in a milling machine. Measurement of forces during welding is a difficult task. Many dynamic measuring devices such as dynamometers are available but each have their own advantages and disadvantages. A new approach to measure force while performing weld is discussed. First, incorporation of FSW in PKM 5-axes milling machine is done. The head of the machine is modified to support higher force levels that are generated during FSW. With the help of the NC-Controller, the force values are retrieved from the axes of the machine while performing weld through actuators. Forces were also measured from load cell and compared to estimate the quality of measurement.
Combined Study of Damage and Damping Phenomenon in Coated Contacts at Ambient Temperature
Authors: Fortes Da Cruz Julien , Lemaire-Caron Isabelle , Inglebert Geneviève , Durand Anne-Marie , Merhej Rafic
Published: August 2013

Fretting damage occurs in mechanisms submitted to vibrations which result in small amplitude oscillatory sliding motion between surfaces. The damage is either crack initiation (fatigue damage) or wear, adhesion, transfer (wear damage) depending on displacement amplitude. Aircraft and helicopters design methods tend to lighten mechanical parts, thus increasing the vibratory levels generated by engines, aerodynamic flow or during taking off and landing phases. Higher displacement amplitude may cause a slip from fatigue oriented damage to wear dominant fretting modes, dramatically decreasing the structures lifespan.
Requirements for Design and Environmental Assessment of Products
Authors: Kota Srinivas , Brissaud Daniel , Zwolinski Peggy
Published: August 2013

Companies can have competitive advantage if their products are developed with the help of users and their practice in mind. Product development needs to include user views in the design [1] as the changes to product proposals in design stage needs less effort and time and has major influence on later stages. User-centered design methods have been proposed and implemented. Virtual reality technology has been developed to support these design methods. Advances in virtual reality technologies help realize virtually not only the products but the environment in which they can be used and the actors who use them. This research aims at investigating the eco-design methods and the technology supporting them. A huge challenge in eco-design is to make clear the environmental potential of products for both the engineer and the user. The paper deals with the use of virtual reality technology to see how it can help both designer and user in design and assessment of product and its use to reduce environmental impact. Different studies are reported in literature [2], [3], and [4] but do not address the environmental properties. The paper reviews the literature to propose the requirements of a user-centered eco-design method and investigates the potential benefits of the holographic technology for this purpose.
Time-Frequency Analyzing of Acoustic Emission Signals in Drilling of Glass/Epoxy Composites
Authors: Heidary Hossein , Karimi Navid Zarif , Najafabadi Mehdi Ahmadi , Minak Giangiacomo , Zucchelli Andrea
Published: August 2013

Drilling is a dynamic process which causes some defects in composite materials such as delamination, fiber pull out and matrix cracking. Because of non-stationary behavior of drilling process, using online method to monitor these damage mechanisms is inevitable. In this paper, acoustic emission signals and wavelet analysis are applied to monitor drilling action from entry to exit. The results show that the selected monitoring indices from the time domain parameters and wavelet packet coefficients are capable of detecting the drilling stages and damage mechanisms during the process effectively.
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.
Indentation of a Functionally Graded Plate by a Rigid Spherical Indenter in the Presence of a Semi-Elliptic Surface Crack
Authors: Nikbakht Ali , Arezoodar Alireza Fallahi , Sadighi Mojtaba , Lari Ali Tale Zadeh
Published: August 2013

Graded materials, also known as functionally graded materials (FGMs), are multiphase composites mainly composed of a ceramic and a metal; thus, they exploit the heat, oxidation and corrosion resistance typical of ceramics, and the strength, ductility and toughness typical of metals. These materials are mainly used as heat barriers. In addition, many of the present and potential applications of FGMs involve contact problems. On the other hand, the production process of FGMs is somewhat complex and leaves some defects in the produced structure. One of the most important defects in such structures is surface cracks. Here, the combination of the contact and crack problems is investigated in a functionally graded rectangular plate containing a semi–elliptic surface crack indented by a frictionless rigid spherical indenter. The plate is simply supported and the crack is located in the middle of the plate surface in the tension part. The crack surface is parallel to one of the plate edges. The gradient of mechanical properties variation is considered through the thickness of the plate and the volume fraction distribution of the constituting phases is modeled by a polynomial function and the Poisson’s ratio is kept constant. The analyzing of the problem is divided into two steps. At the first step, for an uncracked plate the equations of equilibrium are derived in terms of the displacement field and are solved numerically to find the contact rule. As the second step in studying the problem, the contact problem of a cracked plate is modeled by using ABAQUS finite element package. The aim of this step is to find the effect of the presence of the crack on the contact rule. The optimum mesh for the ABAQUS model is found by using the results of the first step. In order to do so, an ABAQUS model is created for the uncracked plate. The analytical results and the obtained results from ABAQUS for specified plate and indenter dimensions and material properties are compared. After finding the optimum mesh, a crack is added to the ABAQUS model of the plate under contact loading. The effects of gradient changes and indenter dimensions on the contact rule and stress distribution at the crack tip are then investigated by using the obtained ABAQUS model. The acquired results show that the influence of the material nonhomogeneity on the stress distribution around the crack tip and in the plate (uncracked and cracked) and contact rule can be quite significant. In general, increasing the overall volume fraction of the metal phase increases the load carrying capacity in an uncracked plate. In a cracked plate, the changes in material distribution as well as the changes of the indenter diameter does not affect the results that much.
Parametric Study of the Behavior of a Mechanical Face Seal Operating in Mixed and TEHD Lubrication Regimes
Authors: Nyemeck André Parfait , Brunetière Noël , Tournerie Bernard
Published: August 2013

In this paper, the behavior of a mechanical face seal is analyzed for different operating conditions and designs. For that, a theoretical model including a multiscale approach of the mixed lubrication regime, heat transfer and deformation of the seal rings is used. It has been possible to clearly identify the three different lubrication regimes of a mechanical seal: the mixed lubrication where the friction coefficient decreases, the rough hydrodynamic regime corresponding to an increasing friction and then the thermo-elasto-hydrodynamic (TEHD) regime for which the coefficient of friction is approximately constant. In this work, the influence of the fluid pressure, the seal roughness height, the balance ratio, the rings materials, the dry friction coefficient and viscosity are respectively examined. Generally speaking, the variation of these parameters affects the location of the optimum value of the friction coefficient in the mixed lubrication regime. In the TEHD regime, the temperature is mainly influenced by the materials and the fluid viscosity, which control the amplitude of deformation and heat transfer. A dimensionless parametric analysis has been carried out in order to perform an overall discussion of the results. It is shown that the mixed and rough hydrodynamic lubrication regimes are controlled by the modified duty parameter, while the TEHD regime is controlled by the sealing parameter.
Design and Optimization of a Master-Slave System for Tele-Echography Application
Authors: Essomba T. , Laribi M. A. , Gazeau J. P. , Poisson G. , Zeghloul S.
Published: August 2013

This paper introduces the research carried out on the design of a robotized teleechography system. Such a system is composed of a master control device and a slave robotic manipulator. Our objective is to contribute to the French Agence National de Recherche (ANR) project PROSIT by designing both devices. To define the kinematic architecture, we had proposed an approach based on the analysis of the expert gesture as a first step of the design process. We have used a motion capture system to study the ultrasound examination gesture and to define the kinematic specifications for the proposed manipulator. A new kind of architecture was selected: the spherical parallel mechanism (SPM). We have chosen it because it reaches the constraint requirements. The kinematic architecture was synthesized by executing a real-coded genetic algorithm (GA). We integrated optimization criteria in the synthesis of the selected architecture. We have fixed a minimum required workspace and we have chosen to optimized the SPM in terms of dexterity and compacity. Another important part of our research was to design a haptic device to provide a very intuitive control of the tele-operated robot. We have opted for a free hand interface that integrates an active force control and feedback. An Inertial Measurement Unit (IMU) has been integrated. The data collected from the IMU that we integrated are processed by a Kalman Filter. But we have modified this predictor-estimator tool from the state of art to adapt its behavior with respect to the type of motion done by the operator. Experimentations via our motion capture system have demonstrated the accuracy of this orientation control strategy. The final step will be the experimental and clinical validation on real patients.