Artículos de revistas sobre el tema "Deformable Parts Model"

In this paper, we introduce the high performance Deformable part models from object detection into human action recognition and localization and propose a unified method to detect action in video sequences. The Deformable part models have attracted intensive attention in the field of object detection. We generalize the approach from 2D still images to 3D spatiotemporal volumes. The human actions are described by 3D histograms of oriented gradients based features. Different poses are presented by mixture of models on different resolutions. The model autonomously selects the most discriminative 3D parts and learns their anchor positions related to the root. Empirical results on several video datasets prove the efficacy of our proposed method on both action recognition and localization.

Traveltime tomography relies on broad ray-angle coverage to constrain the spatial location of velocity anomalies. When ray-angle coverage is narrow, cell or grid tomography can be plagued by smearing artifacts bearing imprints of the raypaths. Multiscale deformable-layer tomography (DLT), which inverts for the geometry of velocity interfaces instead of velocity, can be more effective than grid-based tomography in mitigating such artifacts, especially when velocity values are known for parts of the model. The DLT model consists of geologically sensible layers represented by triangular prisms. In areas of good ray coverage, DLT can be used to invert simultaneously for layer velocities as well as interface geometry. Tests of synthetic models of crosswell refraction, 2D tomostatics, and 3D vertical seismic profiling (VSP) first-arrival data sets show that DLT can produce solutions superior to those produced by cell- or grid-based tomography.

This paper proposes a robot gripper in polymeric material for solid micro-meso parts. The gripper is developed using a light-weight, highly deformable and low cost material, that allows elastic deformations. The proposed solution consists of a simple geometry, incorporating the complexity of the mechanical transmission in the non-linear high deformations of the flexible elements of the device. This choice permits to grip multi-sizes objects. The design approach focuses on Ludwick material model, that describes deformable materials with a nonlinear elastic behavior. The kinematics of the gripper is presented and the results are verified with the finite element analysis. Finally, the gripper was fabricated and validated through a set of experimetal tests. The obtained resulsts confirmed the theoretical and simultion models. The maximum opening and force of the gripping jaws are 1,500 μm and 155 mN, repsectively. Nevetheless further performances may be obtained using different geometrical choices developed in the kinematic analysis.

Movement analysis of infants’ body parts is momentous for the early detection of various movement disorders such as cerebral palsy. Most existing techniques are either marker-based or use wearable sensors to analyze the movement disorders. Such techniques work well for adults, however they are not effective for infants as wearing such sensors or markers may cause discomfort to them, affecting their natural movements. This paper presents a method to help the clinicians for the early detection of movement disorders in infants. The proposed method is marker-less and does not use any wearable sensors which makes it ideal for the analysis of body parts movement in infants. The algorithm is based on the deformable part-based model to detect the body parts and track them in the subsequent frames of the video to encode the motion information. The proposed algorithm learns a model using a set of part filters and spatial relations between the body parts. In particular, it forms a mixture of part-filters for each body part to determine its orientation which is used to detect the parts and analyze their movements by tracking them in the temporal direction. The model is represented using a tree-structured graph and the learning process is carried out using the structured support vector machine. The proposed framework will assist the clinicians and the general practitioners in the early detection of infantile movement disorders. The performance evaluation of the proposed method is carried out on a large dataset and the results compared with the existing techniques demonstrate its effectiveness.

In explicit finite element simulations, a technique called deformable-to-rigid (D2R) switching is used routinely to reduce the computation time. Using the D2R option, the deformable parts in the model can be switched to rigid and reverted back to deformable when needed during the analysis. The time of activation of D2R however influences the overall dynamics of the system being analyzed. In this paper, a theoretical basis for the selection of time of rigid switching based on system energy is established. A floating oscillator problem is investigated for this purpose and closed-form analytical expressions are derived for different phases in rigid switching. The analytical expressions are validated by comparing the theoretical results with numerical computations.

Due to the development of the automotive and aeronautical industries, and the impossibility of pro-typing of the flexible parts because of the large real dimension as well as the behavior of this type of parts during the assembly, the tolerance of the flexible parts become an essential step in aeronautical manufacturing. Therefore the tolerance of plates in the assembly of mechanical systems is one of the key stages in the creation of a product in the automotive and aeronautical industries. This paper deals in the first stage a presentation of the tolerance of deformable mechanisms, through the illustration of the general problem. In order to study in the second stage the model of simulation of the variation of deformable (flexible) mechanisms, using the Influence Coefficient Method taking into account the effects of contact between the surface and including welding distortion. Finally the modeling of a mechanism of this type through an example with a view to an analysis of tolerances.

Because of the drawbacks of standard lumped mass–spring models discussed at the beginning of this paper, a new approach for simplified modeling of frontal impacts appropriate for early phase crashworthiness design is proposed. It is based on a first step, the Geometry Space Model, representing the real location of the structural components with deformable, non-deformable, and gap parts. This is then transformed by a new algorithm into the Deformation Space Model which considers only the available free deformation lengths and can be used to assess the correct deformation modes of complex structural systems. These developments are embedded in a wider research field, already published, where Solution Spaces are established for set-based design of the force–displacement curves for all springs. Together with this Solution Space technology, the proposed new simplified modeling approach for frontal impacts will make early phase development more efficient in the future.

The object of the present study is to investigate the dynamic of plane grinding by the tool with random distribution of abrasive grains, owning random geometric characteristics. The model is based on the consideration of machining system’s dynamical deformable characteristics, which have influence on the workpiece’s displacement under grinding process. The excitation of vibrations has significant effects on precision and surface quality, which is especially important in machining spatial parts, such as turbine blades.

The continuous flexible roll forming process is a novel sheet metal forming technique for effectively manufacture of three-dimensional surface parts. In this study, two types of finite element (FE) models were developed under the ABAQUS/Explicit environment. The difference of the two models is that the rolls are defined as discrete rigid bodies in model No.1 and are deformable in model No.2. An experiment was carried out using the continuous sheet metal forming setup. The comparison of the numerical computation results with the experimental results shows that the model No.2 can be used for the shape prediction of continuous flexible roll forming process well.

Mobility control is one of the most essential parts of planetary rovers’ research and development. The goal of this research is to let the planetary rovers be able to achieve demand of motion from upper level with satisfied control performance under the rough and deformable planetary terrain that often lead to longitudinal slip. The longitudinal slip influences the mobility efficiency obviously, especially on the major deformable slopes. Compared with the past works on normal stiff terrains, properties of soil and interaction between wheels and soil should be considered additionally. Therefore, to achieve the final goal, in this paper, wheel-soil dynamic model for six-wheel planetary rovers while climbing up deformable slopes with longitudinal slip is first built and control based in order to account for slip phenomena. These latter effects are then taken into account within terramechanics theory, relying upon nonlinear control techniques; finally, a robust adaptive fuzzy control strategy with longitudinal slip compensation is developed to reduce the effects induced by slip phenomena and modeling error. Capabilities of this control scheme are demonstrated via full scale simulations carried out with a six-wheel robot moving on sloped deformable terrain, whose real time was computed relying uniquely upon RoSTDyn, a dynamic software.

Vehicle detection plays an important role in safe driving assistance technology. Due to the high accuracy and good efficiency, the deformable part model is widely used in the field of vehicle detection. At present, the problem related to reduction of false positivity rate of partially obscured vehicles is very challenging in vehicle detection technology based on machine vision. In order to address the abovementioned issues, this paper proposes a deep vehicle detection algorithm based on the dual-vehicle deformable part model. The deep learning framework can be used for vehicle detection to solve the problem related to incomplete design and other issues. In this paper, the deep model is used for vehicle detection that consists of feature extraction, deformation processing, occlusion processing, and classifier training using the back propagation (BP) algorithm to enhance the potential synergistic interaction between various parts and to get more comprehensive vehicle characteristics. The experimental results have shown that proposed algorithm is superior to the existing detection algorithms in detection of partially shielded vehicles, and it ensures high detection efficiency while satisfying the real-time requirements of safe driving assistance technology.

Pedestrians are vulnerable road users who are at high risks in a road traffic collision with motor vehicles. A large number are getting killed in traffic accidents each year, the majority of them being children and senior citizens. During impact with an automobile, pedestrians suffer multiple impacts with the bumper, hood and windscreen. Fatality is seen mostly due to the head injuries obtained by the pedestrians. Thus this paper aims to introduce the development and validation of a simplified hybrid vehicle front end profile for the mitigation of head injury. The vehicle model is represented by a multi body windscreen and finite element cowl, hood and bumper. A two step validation procedure is performed, firstly the crash kinematics validation to determine the overall kinematics and fall pattern of the pedestrian during impact. Secondly, the hybrid vehicle model is tested against the pedestrian injury criteria values for pertinent body parts namely the neck, sternum, lumbar, femur and tibia. The hybrid vehicle model is made to impact an adult human dummy model obtained from TNO (TASS Netherlands). The injury criterias are reprensented through the Head Injury Criteria (HIC), neck compression force, sternum and tibia accelerations and lumbar and femur bending moments. The simulation results were compared to the experimental values and a good correlation was achieved.

Detection of instrument tip in retinal microsurgery videos is extremely challenging due to rapid motion, illumination changes, the cluttered background, and the deformable shape of the instrument. For the same reason, frequent failures in tracking add the overhead of reinitialization of the tracking. In this work, a new method is proposed to localize not only the instrument center point but also its tips and orientation without the need of manual reinitialization. Our approach models the instrument as a Conditional Random Field (CRF) where each part of the instrument is detected separately. The relations between these parts are modeled to capture the translation, rotation, and the scale changes of the instrument. The tracking is done via separate detection of instrument parts and evaluation of confidence via the modeled dependence functions. In case of low confidence feedback an automatic recovery process is performed. The algorithm is evaluated on in vivo ophthalmic surgery datasets and its performance is comparable to the state-of-the-art methods with the advantage that no manual reinitialization is needed.

In this paper, a finite element model of a two-dimensional orthogonal metal cutting process is used to simulate the chip formation, cutting forces, stress, strain and temperature distributions. Two deformable parts are involved in this model: the workpiece and the cutting tool. To make the results of the simulation agree the orthogonal cutting test better, the separation surface between the chip and the machined surface is not predefined in this simulation. The chip-separation criterion is based on the Johnson and Cook law. This work will help as a reference to tackle more complex cutting processes such as oblique and discontinuous cutting.

Technological advances in solid organ tissue engineering that rely on the assembly of small tissue-building parts require a novel transport method suited for soft, deformable, living objects of submillimeter- to centimeter-length scale. We describe a technology that utilizes membrane flow through a gripper to generate optimized pressure differentials across the top and bottom surfaces of microtissue so that the part may be gripped and lifted. The flow and geometry parameters are developed for automation by analyzing the fluid mechanics framework by which a gripper can lift tissue parts off solid and porous surfaces. For the axisymmetric part and gripper geometries, we examine the lift force on the part as a function of various parameters related to the gripper design, its operation, and the tissue parts and environments with which it operates. We believe our bio-gripping model can be used in various applications in high-throughput tissue engineering.

This paper introduces a complex multi-body dynamics model which is established to simulate the dynamic behaviors of a multi-stage hybrid planetary gearing based on the finite element method and the software ADAMS. The finite element method is used to introduce deformable ring-gears and sun-gears by using 3D brick units. A whole multi-body dynamics model is established in the software ADAMS. Mesh stiffness variation excitation and gear tooth contact loss are intrinsically considered. A rich spectrum of dynamic phenomena is shown in the multi-stage hybrid planetary gearing. The results show that the static strength of main parts of the gearing is strong enough and the main vibration and noises are excited by the dynamic mesh forces acting on the tooth of planet-gears and ring-gears.

A model is presented which enables the simulation of the three-dimensional static and dynamic behavior of planetary/epicyclic spur and helical gears with deformable parts. The contributions of the deflections of the ring gear and the carrier are introduced via substructures derived from 3D finite element models. Based on a modal condensation technique, internal gear elements are defined by connecting the ring-gear substructure and a planet lumped parameter model via elastic foundations which account for tooth contacts. Discrete mesh stiffness and equivalent normal deviations are introduced along the contact lines, and their values are recalculated as the mating flank positions vary with time. A constraint mode substructuring technique is used to simulate the planet carrier as a superelement which is connected to the planet center. Planetary/epicyclic gear models are completed by assembling lumped parameter sun gear/planet elements along with shaft elements, lumped stiffness, masses and inertias. The corresponding equations of motion are solved by combining a time-step integration scheme and a contact algorithm for all simultaneous meshes. Several quasistatic and dynamic results are given which illustrate the potential of the proposed hybrid model and the interest of taking into account ring gear and carrier deflections.

Within the framework of Newtonian kinematics the local vorticity vector is introduced and averaged with respect to global earth geometry, namely the ellipsoid of revolution. For a deformable body like the earth the global vorticity vector is defined as the earth rotation. A decomposition of the Lagrangean displacement and of the Lagrangean vorticity vector into vector spherical harmonics, namely into spheroidal and toroidal parts, proves that the global vorticity vector only contains toroidal coefficients of degree and order one (polar motion) and toroidal coefficients of degree one and order zero (length of the day) in the case of an ellipsoidal earth. Once we assume an earth model of type ellipsoid of revolution the earth rotation is also slightly dependent on the ellipsoidal flattening and the radial derivative of the spheroidal coefficients of degree two and order one.

In our present days numerical simulation became an important tool of engineering. Numerical simulation methods allow quantitative examination of the complex processes and phenomena in the general area of physics and also provide an insight in their dynamic evolution and even can become important tools for the discovery of new phenomena. In essence, the numerical simulation transfer important aspect of physical reality in discrete forms of mathematical description recreates and solves the problems on computer and finally, highlights issues that the analyst required. This modern numerical method approach, attacks the original problems in all their details on a much larger platform with a much smaller number of assumptions and approximations, in comparison to traditional methods. Transposition of the physics problems in the virtual space, governed by the force of computers, numerical simulation - as scientific approach - is becoming increasingly interesting for many fields of research. Basically, by means of numerical simulation are addressed fields such as mechanics deformable solids, fluid mechanics, aerodynamics, biomechanics, astrophysics. Numerical simulations follow a similar procedure to all the scientific approach, which consists in going through several stages, as follows: the phenomenon, the physical model, mathematical model, discrete model, and coding, numerical solution. In the plastic deformation of metals are involved, besides the mechanical properties and some thermal properties because even if the process is applied in the initial state to a cold material, along the process changes occur because of friction between materials and tools and transformation of plastic mechanical work into heat. Basic mechanical properties of the materials are underline through characteristic diagrams of materials obtained in simple tests of traction and compression. These tests were carried out in the Polytechnic University of Bucharest, Romanian Research & Development Institute for Gas Turbines COMOTI, Institute for Calculating and Testing Aero-Astronautic Structures STRAERO, SC UPS PILOT ARM Ltd, and Asachi Technical University of Iasi. To achieve the major objectives of the numerical simulation of the technological process of cold plastic deformation, are incorporated into the physical model three types of surfaces: cylindrical, conical and profiled. The sizes of the initial geometry were established in accordance with the basic dimensions of processed products by this method. For delimiting surfaces to be machined, the addition of grip (the tail) has a reduced diameter. Geometric models provide strength and rigidity needed for safely and accurately processing technology of cold plastic deformation. Geometric models and specimens which had been subjected to tensile tests, compression and hardness were made in the Glass Factory, Chisinau, Moldova.

In this survey we present a complete landscape of joint object detection and pose estimation methods that use monocular vision. Descriptions of traditional approaches that involve descriptors or models and various estimation methods have been provided. These descriptors or models include chordiograms, shape-aware deformable parts model, bag of boundaries, distance transform templates, natural 3D markers and facet features whereas the estimation methods include iterative clustering estimation, probabilistic networks and iterative genetic matching. Hybrid approaches that use handcrafted feature extraction followed by estimation by deep learning methods have been outlined. We have investigated and compared, wherever possible, pure deep learning based approaches (single stage and multi stage) for this problem. Comprehensive details of the various accuracy measures and metrics have been illustrated. For the purpose of giving a clear overview, the characteristics of relevant datasets are discussed. The trends that prevailed from the infancy of this problem until now have also been highlighted.

The article defines and compares the obtained sediments based on the results of applying the current regulatory methodology of the set of rules 22.13330.2016 "Foundations of buildings and structures" and numerical calculations using various models of the soil base implemented in the SCAD office software package, using the example of a frame-monolithic building of the residential complex which is called "Novaya zhizn" in Belgorod. A brief overview of methods for joint calculation of the foundation and aboveground parts using various models of the ground base: Pasternak with two bed coefficients, variable area bed coefficients in the sattilite CROSS program and the model of linear deformable half – space implemented in SP 22.13330.2016. Analytical calculation of the sediment value for set of rules 22.13330.2016 is performed "manually" by the method of layer-by-layer summation. The numerical calculation of the frame-monolithic building is performed as a single system "building-foundation – base". The values of sediments and bed coefficients C1 and C2 based on the results of numerical calculation are presented in the form of graphical isofields of displacements and bed coefficients. Based on the results of analytical and numerical calculations, the main conclusions are made and recommendations were presented on the applicability of each of the considered models of soil bases

Visual-based vehicle detection has been studied extensively, however there are great challenges in certain settings. To solve this problem, this paper proposes a probabilistic framework combining a scene model with a pattern recognition method for vehicle detection by a stationary camera. A semisupervised viewpoint inference method is proposed in which five viewpoints are defined. For a specific monitoring scene, the vehicle motion pattern corresponding to road structures is obtained by using trajectory clustering through an offline procedure. Then, the possible vehicle location and the probability distribution around the viewpoint in a fixed location are calculated. For each viewpoint, the vehicle model described by a deformable part model (DPM) and a conditional random field (CRF) is learned. Scores of root and parts and their spatial configuration generated by the DPM are used to learn the CRF model. The occlusion states of vehicles are defined based on the visibility of their parts and considered as latent variables in the CRF. In the online procedure, the output of the CRF, which is considered as an adjusted vehicle detection result compared with the DPM, is combined with the probability of the apparent viewpoint in a location to give the final vehicle detection result. Quantitative experiments under a variety of traffic conditions have been contrasted to test our method. The experimental results illustrate that our method performs well and is able to deal with various vehicle viewpoints and shapes effectively. In particular, our approach performs well in complex traffic conditions with vehicle occlusion.

In electronic manufacturing systems, the design of the robotic hand is important for successful accomplishment of the assembly task, and also for human and robot coworker coordinated assembly. Due to the restrictions on the architecture of traditional robotic hands, the status of assembly parts, such as position and rotation during the assembly process cannot be detected effectively. In this research, an intelligent robotic hand – i-Hand, equipped with multiple small sensors – is designed and built for this purpose. Mating connectors by robot, as an experimental case in this paper, is studied to evaluate i-Hand performance. A new model that converts the traditional time-zone-driven model to an event-driven model is proposed to describe the process ofmating connectors, within which, most importantly, the distance between the connector and deformable Printed Circuit Board (PCB) is detected by i-Hand. The generated curve has provided more robust parameters than our previously studied Fault Detection and Diagnosis (FDD) classifier. Various possible situations during assembly are considered and handled based on this event-driven work flow. The effectiveness of our proposed model and algorithm is proven in experiments.

This paper presents a technology of making coupled simulations of weakly deformable bodies moving in elastoplastic environment and defining its mode of deformation. Calculation of penetration of a projectile is made by EGAK methods on a fixed calculating mesh implying that the projectile is rigid and its inner structure is unimportant. Fluid flow is calculated in a noninertial base that is connected with the stationary projectile (using BODY-3D method). Mode of deformation of the projectile is calculated on a Lagrangian mesh using software package LOGOS. Finite-element model of the projectile with the required degree of detail is used with real elastoplastic material properties of its structural parts. Loading of the projectile is implemented with an assignment of force boundary condition on its outer surface. Methods of coupling calculations and test results are provided. In this paper, it is shown that test results obtained by this developed technology are in a good agreement with direct modeling on a fixed calculating mesh. As an example of using this technology, calculation results of a penetrator-probe MoonLITE intruding into a soft soil barrier are presented. This penetrator is developed within the scope of MoonLITE mission of studying the Moon and can deepen into moon soil. Results of numerical simulations are in a good agreement with the experimental data, maximum difference for average slow-down rate of the penetrator is 10–15%.

In this study, the energy absorption capacity of a front body of a bus during a frontal crash was investigated. The strength of the bus structure was examined by considering the ECE-R29 European regulation requirements. The nonlinear explicit finite element code LS-DYNA was used for the crash analyses. First, the baseline bus structures without any improvements were analyzed and the weak parts of the front end structure of the bus body were examined. Experimental tests are conducted to validate the finite element model. In the second stage, the bus structure was redesigned in order to strengthen the frontal body. Finally, the redesigned bus structure was compared with the baseline model to meet the requirements for ECE-R29. In addition to the redesign performed on the body, energy absorption capacity was increased by additional energy absorbers employed in the front of bus structure. This study experimentally and numerically investigated the energy absorption characteristics of a steering wheel armature in contact with a deformable mannequin during a crash. Variations in the location of impact on the armature, armature orientation, and mannequin were investigated to determine the effects of the energy absorption characteristics of the two contacting entities.

Knowledge of the different properties of thermoset composite materials is of great importance for the manufacturing of high quality composite parts. The resin bulk modulus is one of them and is essential to define the composite parts compressive behaviour under uniform compression. The evolution of this property with temperature and conversion degree of reaction is a challenging task and has been tentatively measured with a home-made apparatus, named PVTα, on which temperature, volume change and degree of cure are simultaneously recorded. But as the sample is contained in a non-reactive and deformable capsule, which mechanical behaviour may interfere with the measurement, a validation is required. The aim of this work is to develop a finite element model of the problem in order to simulate the thermal mechanical behaviour of the sample and the capsule, and so to validate the measurement process. The multiphysical numerical model accounts for phase change kinetics and non-linear thermal properties as well as thermo-dependent elastic properties, all problems being solved through a strong iterative coupling scheme. Mechanical contact problems between the capsule and the resin sample are handled through a penalization method contact algorithm which enables to capture the effects of chemical and thermal shrinkage in the sample and the capsule. The heterogeneous stress state generated by the material transformation is assumed to induce heterogeneous strain states which may lead to misinterpretations of macroscopic measurements. This model is a first approach and will be improved using a more sophisticated rheological model. Nevertheless, results show that the usual experimental analysis method can be used as long as the gel point is not reached. After a certain conversion degree, the measured bulk modulus is different from the effective one so corrections have to be brought.

We propose and evaluate an automatic segmentation method for extracting striatal brain structures (caudate, putamen, and ventral striatum) from parametricC11-raclopride positron emission tomography (PET) brain images. We focus on the images acquired using a novel brain dedicated high-resolution (HRRT) PET scanner. The segmentation method first extracts the striatum using a deformable surface model and then divides the striatum into its substructures based on a graph partitioning algorithm. The weighted kernelk-means algorithm is used to partition the graph describing the voxel affinities within the striatum into the desired number of clusters. The method was experimentally validated with synthetic and real image data. The experiments showed that our method was able to automatically extract caudate, ventral striatum, and putamen from the images. Moreover, the putamen could be subdivided into anterior and posterior parts. An automatic method for the extraction of striatal structures from high-resolution PET images allows for inexpensive and reproducible extraction of the quantitative information from these images necessary in brain research and drug development.

In this article, the task is to consider the effect of the piston bending in an axial- piston pump under the action of hydraulic force on the kinematics of the pump. The change in kinematics due to the elastic deformation of the piston is estimated by the axial displacement of the piston face. The study takes into account the bias of the plunger in the gap, the elastic bending deformation of the plunger, the contact deformation of the plunger and the cylinder block. The task is considered on three models: a rigid piston in a rigid cylinder block; deformable piston in a rigid cylinder block; deformable piston, block, shoe, and disk. The values of the displacement of the piston, caused by elastic forces and misalignment in the gap depending on its position were obtained for the first time as a result of the analysis. The problem is solved both analytically and numerically using the finite element method. In the analytical solution of the problem, the piston is represented as a beam supported by pin and roller at the points of contact of the piston with the walls of the cylinder block. The three-dimensional model of the pump is applied to solve the problem by the finite element method, the contact deformation of the piston and the block is considered. According to the simulation results, the displacement of the piston is obtained depending on the position of the piston. The results of modeling an analytical model are presented in the form of a smooth function, and the results of numerical simulation using the finite-element method obtained for several points are interpolated by a smooth function. The conclusions suggest that the greatest deformations are achieved in the piston located at the bottom dead center, and the gap between the piston and the sleeve and the overall stiffness of the contact parts have the greatest effect. The results of the work can be used to correct the geometrical parameters of a heavily loaded aviation axial-plunger pump to reduce flow and pressure pulsations caused by the kinematics of the pump.

We aimed to study the static deformation of geometrically nonlinear shell-type structures on the basis of micromorphic theory. Employing the most comprehensive model in the micro-continuum field, shells in low-dimensions and made of inhomogeneous materials are precisely investigated. The seven-parameter two-dimensional (2D) kinematic model is used which satisfies three-dimensional (3D) constitutive relations and represents the macro-deformation components in mid-surface area of the shell. Also, in the framework of micromorphic continua with three deformable director vectors, nine micro-deformation degrees of freedom, including micro-scale rotations, shears and stretches, are taken into account. Utilizing the energy approach in the convected curvilinear coordinate system leads to the general derivation of the variational formulations in Lagrangian description. High-order stress–strain relations are obtained via introducing the size-dependent as well as size-independent elasticity tensors for the isotropic micromorphic solid. Finally, an equivalent matrix–vector form of representation is proposed to facilitate the solution procedure of the extracted tensor-based formulation. Determining the kinetic and kinematic fields in terms of 16 macro and micro-deformation components, provides the opportunity to directly implement the interpolation-based solution methodologies, such as the finite element isogeometric analysis presented in Part II of this study. Two parts of the article, that are organized to be independent, contribute to the literature respectively from theoretical and computational perspectives.

Abstract. Dry-snow slab avalanche release is preceded by a fracture process within the snowpack. Recognizing weak-layer collapse as an integral part of the fracture process is crucial and explains phenomena such as whumpf sounds and remote triggering of avalanches from low-angle terrain. In this two-part work we propose a novel closed-form analytical model for a snowpack under skier loading and a mixed-mode failure criterion for the nucleation of weak-layer failure. In the first part of this two-part series we introduce a closed-form analytical model of a snowpack accounting for the deformable layer. Despite the importance of persistent weak layers for slab avalanche release, no simple analytical model considering weak-layer deformations is available. The proposed model provides deformations of the snow slab, weak-layer stresses and energy release rates of cracks within the weak layer. It generally applies to skier-loaded slopes as well as stability tests such as the propagation saw test. A validation with a numerical reference model shows very good agreement of the stress and energy release rate results in several parametric studies including analyses of the bridging effect and slope angle dependence. The proposed model is used to analyze 93 propagation saw tests. Computed weak-layer fracture toughness values are physically meaningful and in excellent agreement with finite element analyses. In the second part of the series (Rosendahl and Weißgraeber, 2020) we make use of the present mechanical model to establish a novel failure criterion crack nucleation in weak layers. The code used for the analyses in both parts is publicly available under https://github.com/2phi/weac (last access: 6 January 2020) (2phi, 2020).

Most existing facial landmark detection algorithms regard the manually annotated landmarks as precise hard labels, therefore, the accurate annotated landmarks are essential to the training of these algorithms. However, in many cases, there exist deviations in manual annotations, and the landmarks marked for facial parts with occlusion and large poses are not always accurate, which means that the “ground truth” landmarks are usually not annotated precisely. In such case, it is more reasonable to use soft labels rather than explicit hard labels. Therefore, this paper proposes to associate a bivariate label distribution (BLD) to each landmark of an image. A BLD covers the neighboring pixels around the original manually annotated point, alleviating the problem of inaccurate landmarks. After generating a BLD for each landmark, the proposed method firstly learns the mappings from an image patch to the BLD of each landmark, and then the predicted BLDs are used in a deformable model fitting process to obtain the final facial shape for the image. Experimental results show that the proposed method performs better than the compared state-of-the-art facial landmark detection algorithms. Furthermore, the proposed method appears to be much more robust against the landmark noise in the training set than other compared baselines.

Despite significant recent progress, machine vision systems lag considerably behind their biological counterparts in performance, scalability, and robustness. A distinctive hallmark of the brain is its ability to automatically discover and model objects, at multiscale resolutions, from repeated exposures to unlabeled contextual data and then to be able to robustly detect the learned objects under various nonideal circumstances, such as partial occlusion and different view angles. Replication of such capabilities in a machine would require three key ingredients: (i) access to large-scale perceptual data of the kind that humans experience, (ii) flexible representations of objects, and (iii) an efficient unsupervised learning algorithm. The Internet fortunately provides unprecedented access to vast amounts of visual data. This paper leverages the availability of such data to develop a scalable framework for unsupervised learning of object prototypes—brain-inspired flexible, scale, and shift invariant representations of deformable objects (e.g., humans, motorcycles, cars, airplanes) comprised of parts, their different configurations and views, and their spatial relationships. Computationally, the object prototypes are represented as geometric associative networks using probabilistic constructs such as Markov random fields. We apply our framework to various datasets and show that our approach is computationally scalable and can construct accurate and operational part-aware object models much more efficiently than in much of the recent computer vision literature. We also present efficient algorithms for detection and localization in new scenes of objects and their partial views.

Blood cell interaction with vascular endothelium is important in microcirculation, where rolling adhesion of circulating leukocytes along the surface of endothelial cells is a prerequisite for leukocyte emigration under flow conditions. HL-60 cell rolling adhesion to surface-immobilized P-selectin in shear flow was investigated using a side-view flow chamber, which permitted measurements of cell deformation and cell-substrate contact length as well as cell rolling velocity. A two-dimensional model was developed based on the assumption that fluid energy input to a rolling cell was essentially distributed into two parts: cytoplasmic viscous dissipation, and energy needed to break adhesion bonds between the rolling cell and its substrate. The flow fields of extracellular fluid and intracellular cytoplasm were solved using finite element methods with a deformable cell membrane represented by an elastic ring. The adhesion energy loss was calculated based on receptor-ligand kinetics equations. It was found that, as a result of shear-flow-induced cell deformation, cell-substrate contact area under high wall shear stresses (20 dyn/cm2) could be as much as twice of that under low stresses (0.5 dyn/cm2). An increase in contact area may cause more energy dissipation to both adhesion bonds and viscous cytoplasm, whereas the fluid energy input may decrease due to the flattened cell shape. Our model predicts that leukocyte rolling velocity will reach a plateau as shear stress increases, which agrees with both in vivo and in vitro experimental observations.

Purpose The purpose of this paper is to investigate the problem of optimizing geometrical and physical parameters of a stepped shell that maximize its rigidity and strength for given overall shell dimensions and fixed weight equal to the weight of a shell of constant thickness. Design/methodology/approach A mathematical model of the construction’s stress-strain state is described by solving a system of differential equations for each of the constituent parts of the shell, conjugation conditions on the division lines and boundary conditions. The stated optimization problem is reduced to a nonlinear programming problem, which is solved by the deformable polyhedron method in combination with the method of direct search and using the parallel computing package in the Wolfram Mathematica software application. Findings As follows from the results of the calculation, optimizing the shell parameters allows for a substantial increase in rigidity (decrease of the greatest deflection) and strength (increase of the load-carrying capacity) of the shell of constant stepwise thickness, as opposed to a shell of constant thickness, with constant weight and dimensions. Originality/value A problem of optimal design of a cylindrical composite panel of piecewise constant thickness is solved in the presented work. Numerical examples demonstrate that a substantial increase in rigidity and strength of a stepped composite shell can be achieved by the optimal choice of its geometrical and physical parameters.

All animals use mechanosensors to help them move in complex and changing environments. With few exceptions, these sensors are embedded in soft tissues that deform in normal use such that sensory feedback results from the interaction of an animal with its environment. Useful information about the environment is expected to be embedded in the mechanical responses of the tissues during movements. To explore how such sensory information can be used to control movements, we have developed a soft-bodied crawling robot inspired by a highly tractable animal model, the tobacco hornworm Manduca sexta . This robot uses deformations of its body to detect changes in friction force on a substrate. This information is used to provide local sensory feedback for coupled oscillators that control the robot's locomotion. The validity of the control strategy is demonstrated with both simulation and a highly deformable three-dimensionally printed soft robot. The results show that very simple oscillators are able to generate propagating waves and crawling/inching locomotion through the interplay of deformation in different body parts in a fully decentralized manner. Additionally, we confirmed numerically and experimentally that the gait pattern can switch depending on the surface contact points. These results are expected to help in the design of adaptable, robust locomotion control systems for soft robots and also suggest testable hypotheses about how soft animals use sensory feedback.

The paper presents a new refined-modified solution of the fundamental two-dimensional problem of the elasticity theory on the perpendicular application to the boundary of the half-plane of a concentrated-linear constant load. In contrast to the similar classical Fleman problem, which is a special case of a simple radial stress state, all three stress components, two normal and one tangent, as well as an additional geometric parameter characterizing the width of the site of the external local force’s actual distribution have been taken into consideration. In addition, on the basis of the classical interpretation of plane deformation, the known contradictions are eliminated that are associated with the uncertainty of the angular displacement at the boundary of the half-space and with the constancy of the second kinematic component in the pursuit of the infinity coordinates of an arbitrary point of the base material. In the course of the research, it is proved that there are cylindrical surfaces where equal tensile stresses act which trajectories have the shape of circles. In a simplified Fleman solution of such curves- isobars are Boussinesq circles with constant the principal compressive stresses. The derived analytical dependences are presented in a rectangular frame of reference, which allows to quantify the following with a high accuracy: 1) stresses in the depth of the base in horizontal and vertical sections; 2) contact pressure and draft of the soil elastic surface under the sole of a rigid long foundation when the base, within the generally accepted assumptions, is assumed to be linearly deformable, homogeneous, isotropic, solid, experiencing a one-time load. The results of the developed generalized physical and mathematical model can serve as a conceptual basis used in solving special fundamental and applied problems of mechanics directly related to the refined calculation of the bearing capacity of various parts and structures, widely used in modern engineering and construction such as bearings, cylindrical rollers, gears, foundations strip foundations, pavements in their steel compaction rolls, etc.

Abstract Scissor bridges are characterized by high mobility and modular structure. A single module-span consists of two spanning parts of the bridge; two main trucks and the support structure. Pin joints are used between modules of the single bridge span. Some aspects of the experimental test and numerical analysis of the scissor-AVLB type bridge operation are presented in this paper. Numerical analyses, presented here, were carried out for the scissors-type BLG bridge with treadways extended as compared to the classical bridge operated up to the present in the Armed Forces of the Republic of Poland. A structural modification of this kind considerably affects any changes in the effort of the force transmitting structure of the bridge. These changes may prove to be disadvantageous to the whole structure because of torsional moments that additionally load the treadways. Giving careful consideration to such operational instances has been highly appreciated because of the possibility of using this kind of bridges while organizing the crossing for vehicles featured with various wheel/track spaces (different from those used previously). The BLG bridge was numerically analysed to assess displacements and distributions of stresses throughout the bridge structure in different loading modes. Because of the complexity of the structure in question and simplifications assumed at the stage of constructing geometric and discrete models, the deformable 3D model of the scissors-type bridge needs verification. Verification of the reliability of models was performed by comparing deflections obtained in the different load modes that corresponded with tests performed on the test stand. It has been shown that the examined changes in conditions of loading the treadways of the bridge are of the greatest effect to the effort of the area of the joint which is attached to the girder bottom. Stress concentrations determined in the analysis are not hazardous to safe operation of the structure

This work involves an analysis of high-chromium high-temperature deformable wieldable nickel alloys for use in GTE repair assemblies. It is shown that the alloys EP868 (VZh98) and Haynes 230 can be used in welded assemblies with an operating temperature of 800-1100 °C. The alloys Nimonic 81, Nimonic 91, IN 935, IN 939, and Nicrotan 2100 GT also have a high potential for use in welded assemblies. They are characterized by a combination of good weldability, high-temperature strength, and resistance to scaling. There have been conducted studies on high-temperature salt corrosion of model nickel alloys. They allowed establishing the patterns of the impact of base metal alloying with chromium, aluminum, titanium, cobalt, tungsten, molybdenum, niobium, tantalum and rare earth metals on the critical temperature of the start of salt corrosion Tcor and the alloy mass loss. It has been established that alloys with a moderate concentration (13-16%) of chromium can possess satisfactory hightemperature corrosion resistance (HTC resistance) under the operating conditions of ship GTE. The HTC resistance of CrAl-Ti alloys improves upon reaching the ratio Ti/Al ˃ 1. Meanwhile, the ratio Ti/Al ˂ 1 promotes the formation of corrosion products with low protective properties. The positive effect of tantalum on the HTC resistance of alloys is manifested at higher test temperatures than that of titanium, and the total content of molybdenum and tungsten in alloys is limited by the condition 8Mo2 – 2W2 = 89. The presence of refractory elements stabilizes the strengthening phase and prevents formation of the ɳ-phase. However, their excess promotes formation of the embrittling topologically close packed (TCP) phases and boundary carbides of an unfavorable morphology. Based on the studies of the HTC resistance, there has been identified a class of model high-temperature corrosionresistant nickel alloys with a moderate or high chromium content (30%), Ti/Al ˃ 1, and a balanced content of refractory and rare-earth elements.

Abstract To evaluate ground deformation resulting from large (~10 m) coseismic strike-slip displacements, we focus on deformation of the Kekerengu fault during the November 2016 Mw 7.8 Kaikōura earthquake in New Zealand. Combining post-earthquake field observations with analysis of high-resolution aerial photography and topographic models, we describe the structural geology and geomorphology of the rupture zone. During the earthquake, fissured pressure bulges (“mole tracks”) initiated at stepovers between synthetic Riedel (R) faults. As slip accumulated, near-surface “rafts” of cohesive clay-rich sediment, bounded by R faults and capped by grassy turf, rotated about a vertical axis and were internally shortened, thus amplifying the bulges. The bulges are flanked by low-angle contractional faults that emplace the shortened mass of detached sediment outward over less-deformed ground. As slip accrued, turf rafts fragmented into blocks bounded by short secondary fractures striking at a high angle to the main fault trace that we interpret to have originated as antithetic Riedel (R′) faults. Eventually these blocks were dispersed into strongly sheared earth and variably rotated. Along the fault, clockwise rotation of these turf rafts within the rupture zone averaged ~20°–30°, accommodating a finite shear strain of 1.0–1.5 and a distributed strike slip of ~3–4 m. On strike-slip parts of the fault, internal shortening of the rafts averaged 1–2 m parallel to the R faults and ~1 m perpendicular to the main fault trace. Driven by distortional rotation, this contraction of the rafts exceeds the magnitude of fault heave. Turf rafts on slightly transtensional segments of the fault were also bulged and shortened—relationships that can be explained by a kinematic model involving “deformable slats.” In a paleoseismic trench cut perpendicular the fault, one would observe fissures, low-angle thrusts, and steeply dipping strike-slip faults—some cross-cutting one another—yet all may have formed during a single earthquake featuring a large strike-slip displacement.

The article develops processes of increase the durability of parts operating under repeated loads, by justifying the parameters of surface plastic deformation (SPD) and cold gas-dynamic coating. The influence on the depth of the reinforced surface layer, the nature of the distribution of the stress-strain state of the material and residual compressive stresses, as well as the value of the used plasticity of the metal, the parameters of the SPD process. The hypothesis is substantiated that the main factor in the formation of residual compressive stresses during SPD is the decrease in metal density, which is associated with the use of the plasticity resource. The model of definition of the used resource of plasticity of metals at SPD is developed, that allows to provide qualitative characteristics of a surface layer of details. Methods for shifting the layer with maximum hardening and residual compressive stresses to the surface of the part by using a deformable tool of smaller dimensions in subsequent passes and gas-dynamic coating before SPD. The vast majority of traditional gas-thermal coating methods occur at significant temperature effects on the surface of the part, which is unacceptable for the surface treated by SPD methods. Cold gas-dynamic spraying provides an allowable temperature regime for the creation of special auxiliary coatings while maintaining the properties of the surface treated by SPD methods. The technology of gas-dynamic coating includes heating the compressed gas (air), feeding it into the nozzle and forming a supersonic air stream in this nozzle, introducing a powder material into this stream, accelerating this material in the nozzle by a supersonic air flow and directing it to the surface of the workpiece. As a result, a special auxiliary coating is formed on the surface of the product, which provides optimal parameters of the SPD process.

In recent years, the economic factor has played an increasingly important role in the selection of technologies for manufacturing machine parts with specified values of normalized parameters of geometric accuracy and quality of working surfaces. As applied to surface plastic deformation processes, this is noticeably manifested in the search for effective friction control methods in the “tool – workpiece” pair, which ultimately determines the distribution pattern and the magnitude of stresses and strains in the workpiece and the tool. It is not possible to obtain a rigorous analytical solution to the problem of establishing a connection between surface conditions, friction, and the stress-strain state of the contacted bodies. In this regard, the construction of mathematical models comes to the fore, the solution of which is possible by numerical methods. The paper presents the results of a numerical study (computational experiment) of a finite-element model of workpiece deformation under various conditions of contact interaction and friction by one of the methods of surface plastic deformation – surface mandrel drilling. The friction coefficient has been chosen as the criterion for assessing the conditions of contact interaction and friction. It is shown that a change in the friction coefficient in the process of surface mandrel has no noticeable effect on the formation of a stress field in the deformable workpiece both in the axial, and in the radial and circumferential directions. At the same time, with an increase in the value of the friction coefficient in the “tool – workpiece” pair and with the associated increase in the force of mechanical resistance to deformation of the workpiece, their growth is observed. A computational experiment has confirmed the presence of non-contact deformations of the workpiece and tool during surface mandrel drilling, as well as as a decrease in the value of residual deformations in the workpiece with a decrease in the coefficient of friction. Balance assessment of contact surface displacements in the workpiece (the inner surface of the hole to be machined) and the tool (mandrel) has shown that the deformations of the tool in the elastic region can lead to a significant decrease in the real tightness of surface mandrel drilling.

It is difficult to introduce highly versatile automation using robots to handling deformable objects such as thread, cloth, wire, long beams, and thin plates in plant production processes, compared to the handling of rigid objects. Office equipment handles deformable objects such as paper and plastic. Problems unique to these objects is caused by speeding up such equipment and demand for upgrading its accuracy. In agriculture and medical care, automatic, intelligent handling of deformable objects such as fruit and animals has long been desired and practical systems sought. Deformable objects whose handling should be versatiley and accurately automated are classified into two groups based on handling: (A) Flexible, mostly thin, fine objects capable of elastic deformation (B) Soft objects easily crushed, such as soft fruits or animals The problem in handling the first group is controlling object deformation of an infinite degree of freedom with a finite number of manipulated variables. In contrast, a significant problem in handling the second group is often how to handle them without exerting excessive stress and how to handle them safely and reliably. The handling of these two groups differ greatly in mechanics and control theory, and this special issue focuses on the first group — flexible objects — mechanical collection and transport studies, control, and software. Recent studies on their handling are classified into four groups for convenience based on handled objects and types of handling task: (a) Control of deformation, internal force, and vibration or path planning of flexible objects (mainly thin plates and beams) using single or multiple manipulators. (b) Task understanding in insertion of elastic into rigid parts and vice versa, and the study of human skills to help robots accomplish these task. (c) Approaches on improved accuracy, intelligent control, and vibration damping in handling and transfer of sheets and strings with low flexural rigidity, represented by paper or wire. (d) Strategies for grasping and unfolding sheets such as cloth whose flexural rigidity is almost nil. For (a), studies are active on deformation control by two robot hands attempting to grasp cloth. 1-3) In the automobile industry, so-called flexible fixtureless assembly systems are advancing in which two robots process or assemble parts in mid-air without a fixed table to reduce lead time and cost. These systems are mostly developed assuming handled parts are rigid. Nguyen et al. work assuming parts such as sheet metal whose deformation must be taken into consideration.1) Nakagaki et al. propose form estimation that considers even plastic deformation in wire handling by robots, in connection with the development of robots for electric wire installation.4) Many studies cover flexible wire as elastic beams,3-9) but comparatively few focus on bending deformation of thin plates. This special edition includes a paper by Kosuge et al. on thin-plate deformation control. Vibration control of grasped objects becomes important as speed increases. Matsuno kindly contributed his paper on optimum path planning in elastic plate handling. In controlling the deformation of elastic bodies, the mechanics of objects handled is often unknown. This special issue features a paper by Kojima et al. on an approach to this problem by adaptive feed-forward control. For (b), we consider three cases: (1) A cylindrical rigid body inserted into a hole on an elastic plate. (2) An elastic bar inserted into a hole on a rigid body. (3) A tubular elastic body put on a cylindrical rigid body. This special issue carries papers on these problems by Brata et al., Matsuno et al., and Hirai. For (2), a paper by Nakagaki et al.10) covers electric wire installation. For (3), the paper by Shima et al.11) covers insertion of a rigid axis into an elastic hose. Robot skill acquisition is an important issue in robotics in general, and the above papers should prove highly interesting and information because they treat studies by comparing robot and human skills in accomplishing work and acquiring concrete skills knowledge. For (c), attempts are made to theoretically analyze sheet handling mechanisms and control developed based on trial and error, and to structure design theory based on such analysis. These attempts are related to the increased accuracy and speed and enhanced intelligence of sheet-handling office automation equipment such as printers, facsimile machines, copiers, and automated teller machines. Yoshida et al. conducted a series of studies on the effects of guides forming paper feed paths and of inertia force of paper by approximating sheets with a chain of discrete masses and springs.12-14) This special edition also features a study on sheet sticking and jamming. Okuna et al. handles a system of similar nature, mechanical studying the form of paper guides.15) Introducing mechanisms to control the positioning of sheets is effective in raising sheet transfer accuracy. Feedback control that regulates feed roller skew angle as a manipulated variable is proposed.16) Increased reliability in separating single sheets from stacked effectively reduces the malfunction rate in sheet-handling equipment. Ways of optimizing the form of sheet-separation rollers17) and estimating frictional force between separation gates and sheets 18) are also proposed. This special issue contains a proposal by Nakazawa et al. of a mechanism that uses reactive sheet buckling force, made in connection with development of a newspaper page turner for the disabled as technology for separating single sheets. Dry frictional force is most widely used for transporting sheets, but is not stable and may even act as an obstacle to improving accuracy. Niino et al. propose a sheet transfer mechanism that uses electrostatic force.19) For improving the accuracy of flexible wire transmission, this special issue carries a study on transporting flexible thin wire through tension control at multiple points, from a study by Morimitsu et al. on optical fiber installation. The thickness of wire used in equipment is becoming increasingly slim and flexible, along with the equipment it is used in. Tension control in the production process is an important factor in the manufacture of such thin wire. Production efficiency constantly calls for increased transfer speed. It has thus become important to estimate air resistance and inertia and to measure and control the tension of running wire. Studies20,21) by Batra, Fraser, et al. which deal the motion of string in the spinning process provide good examples for learning analytical techniques for air drag and inertia. In string vibration where inertia dominates, attempts are made to control vibration by boundary shaking22,23) and feed-forward/back control.24) For (d), highly versatile robots for handling cloth are being developed, and the software technology for automatic cloth selection and unfolding by robot hands is a popular topic.25-27) Ono et al. comment on the nature of problems in developing intelligent systems for handling cloth and similar objects whose bending rigidity is low and which readily fold and overlap—a paper that will prove a good reference in basic approaches in this field. Mechanical analyses are indispensable to studies on (a) through (c). In contrast, information technology such as characteristic variable measurement, image processing, and discrimination, rather than mechanical analyses, play an important roles in studies on (d). This special issue features a study by Hamashima, Uraya et al. on cloth unfolding as an example of such studies. Studies up to now largely assumed that properties of grasped objects did not change environmental influences such as temperature and humidity. Such influence is often, however, a major factor in handling fiber thread and cloth. This special issue has a paper contributed by Taylor, who studies handling method to prevent influence by such environmental factors. The objective of this special issue will have been achieved if it aids those studying the handling of flexible objects by providing approaches and methodologies of researchers whose target objects differ and if it aids those planning to take up study in this field by providing a general view of this field. References: 1) Nguyen, W. and Mills, J., ""Multi-Robot Control For Plexible Fixtureless Assembly of Flexible Sheet Metal Auto Body Parts,"" Proceedings of the 1996 IEEE International Conference on Robotics and Automation, 2340-2345, (1996). 2) Sun, D. and Shi, X. and Liu, Y., ""Modeling and Cooperation of Two-Arm Robotic System Manipulating a Deformable Object,"" Proceedings of the 1996 IEEE International Conference on Robotics and Automation, 2346-2351, (1996). 3) Kosuge, K., Sakaki, M., Kanitani, K., Yoshida, H. and Fukuda, T., ""Manipulation of a Flexible Object by Dual Manipulators,"" IEEE International Conference on Robotics and Automation, 318-323, (1995). 4) Nakagaki, H., Kitagaki, K., Ogasawara, T. and Tukune H., ""Handling of a Flexible Wire -Detecting a Deformed Shape of the Wire by Vision and a Force Sensor,"" Annual Conference on Robotics and Mechatronics (ROBOMEC'96), 207-210, (1996). 5) Wakamatsu, H., Hirai, S. and Iwata, K., ""Static Analysis of Deformable Object Grasping Based on Bounded Force Closure,"" Trans. of JSML, 84-618 (C), 508-515, (1998). 6) Katoh, R. and Fujmoto, T., ""Study on Deformation of Elastic Object By Manipulator -Path Planning of End -Effector-,"" J. of the Robotics Society of Japan, 13-1, 157-160, (1995). 7) Yukawa, T., Uohiyama, M. and Inooka, M., ""Stability of Control System in Handling a Flexible Object by Rigid Arm Robots,"" JSME Annual Conference on Robotics and Mechatronics (ROBOMEC'95), 169-172, (1995). 8) Yukawa, T., Uohiyama, M. and Cbinata, G., ""Handling of a Vibrating Flexible Structure by a Robot,"" Trans. JSME, 61-583, 938-943, (1995). 9) Sun, D. and Liu, Y., ""Modeling and Impedance Control of a Two-Manipulator System Handling a Flexible Beam,"" Trans. of the ASME, 119, 736-742, (1997). 10) Nakagaki, H., Kitagaki, K. and Tukune, H., ""Contact Motion in Inserting a Flexible Wire into a Hole,"" Annual Conference on Robotics and Mechatronics (ROBOMEC'95), 175-178, (1995). 11) Shimaji, S., Brata, A. and Hattori, H., ""Robot Skill in Assembling a Cylinder into an Elastic Hose,"" Annual Conference on Robotics and Mechatronics (ROBOMEC'95), 752-755, (1995). 12) Yoshida, K. and Kawauchi, M., ""The Analysis of Deformation and Behavior of Flexible Materials (1st Reprt, Study of Spring-Mass Beam Model of the Sheet,"" Trans. of JSME, 58-552, 1474-1480, (1992). 13) Yoshida, K., ""Analysis of Deformation and Behavior of Flexible Materials (2nd Report, Static Analysis for Deformation of the Sheet in the Space Formed by Guide Plates),"" Trans. JSME, 60-570, 501-507, (1994). 14) Yoshida, K., ""Dynamic Analysis of Sheet Defofmation Using Spring-Mass-Beam Model,"" Trans. JSME, 63-615, 3926-3932 (1997). 15) Okuna, K., Nishigaito, T. and Shina, Y., ""Analysis of Paper Deformation Considering Guide Friction (Improvement of Paper Path for Paper-Feeding Mechanism),"" Trans. JSME, 60-575, 2279-2284, (1994). 16) Fujimura, H. and Ono, K., ""Analysis of Paper Motion Driven by Skew-Roll Paper Feeding System,"" Trans. JSME, 62-596, 1354-1360, (1996). 17) Shima, Y., Hattori, S., Kobayashi, Y. and Ukai, M., ""Optimum of Gate-Roller Shape in Paper Isolating Methods,"" Conference of Information, Intelligence and Precision Equipment (IIP'96), 61-62, (1996). 18) Suzuki, Y, Hattori, S., Shima, Y. and Ukai, M., ""Contact Analysis of Paper in Gate-Roller Handling Method"", Conference on Information, Intelligence and Precision Equipment (IIP'95), 19-20, (1995). 19) Niino, T., Egawa, S. and Higuchi, T., ""An Electrostatic Paper Feeder,"" J. of the Japan Society for Precision Engineering, 60-12,1761-1765, (1994). 20) Batra, S., Ghosh, T. and Zeidman, M., ""An Integrated Approach to Dynamic Analysis of the Ring Spinning Process , PartII: With Air Drag,"" Textile Research Journal, 59, 416-424, (1989). 21) Fraser, W., Ghosh, T. and Batra, S., ""On Unwinding Yarn from a Cylindrical Package,"" Proceedings of Royal Society of London, A, 436, 479-438, (1992). 22) Jacob, S., ""Control of Vibrating String Using Impedance Matching,"" Proceedings of the American Control Conference (San Francisco),468-472, (1993). 23) Lee, S. and Mote, C., ""Vibration Control of an Axially Moving String by Boundary Control,"" Trans. of the ASME, J. of Dynamic Systems, Measurement, and Control, 118, 66-74, (1996). 24) Ying, S. and Tan, C., ""Active Vibration Control of the Axially Moving String Using Space Feedforward and Feedback Controllers,"" Trans. ASME, J. of Vibration and Acoustics, 118, 306-312, (1996). 25) Ono, E., Ichijo, H. and Aisaka, N., ""Flexible Robotic Hand for Handling Fabric Pieces in Garment Manufacture,"" International Journal of Clothing Science and Technology, 4-5,18-23, (1992). 26) Paraschidis, K., Fahantidis, N, Petridis, V., Doulgeri, Z., Petrou, L. and Hasapis, G, ""A Robotic System for Handling Textile and Non Rigid Flat Materials,"" Computers in Industry, 26, 303-313, (1995). 27) Fahantidis, N., Paraschidis, K, Petridis, V., Doulgeri, Z., Petrou, L. and Hasapis, G., ""Robot Handling of Flat Textile Materials,"" IEEE Robotics & Automation Magazine, 4-1, 34-41, (1997).

In sheet metal assembly, joints are designed to facilitate welding the parts. The three basic joints used in sheet metal assemblies are lap (slip) joints, butt joints, and butt-lap (corner) joints. Each joint configuration has its own variation characteristics. However, the currently available variation analysis methods, such as worst case analysis, root sum squares, etc., are not applicable to deformable sheet metal because they are based on rigid bodies. This paper analyzes the variation characteristics of simple assemblies constructed from the three basic joints, using Mechanistic Variation Simulation. Mechanistic Variation Simulation combines engineering structural models with statistical analysis in predicting deformable sheet metal assembly variation. Furthermore, the variation characteristics of the boxes constructed from the three basic joints are also evaluated. The developed models and analysis provide an improved understanding of sheet metal product design and process design.

To understand flow-induced vibrations of deformable objects, we numerically investigate dynamics of a pressurized elastic ring pinned at one point within a uniform flow by using an immersed-boundary algorithm. The boundary of the ring consists of a fibre with no bending stiffness, which can be modelled as a linear spring with spring constant k and zero unstretched length. The vibration of the ring is decomposed into two parts: a pitching motion that includes a rigid-body rotation and a flexible bending motion in the transverse direction, and a tapping motion in the longitudinal direction. The pitching motion is dominated by the frequency of vortex shedding, whereas the primary frequency of the tapping motion is twice the frequency of vortex shedding. At the Reynolds number of 100, resonance is observed when k ~ 0.2 (k is normalized by the diameter of the undeformed ring, the speed of the upcoming flow and the fluid density). Across the resonance region, abrupt jumps in terms of the motion amplitudes as well as the hydrodynamic loads are recorded. Within the resonance region, the lift force demonstrates a beating phenomenon reminiscent of findings through reduced models and low-degree-of-freedom systems.

Air and blood flow in a set of deformable conduits. Nowadays, computational models of biofluid flow are based on zoomed domains reconstructed from medical image processing. Such modeling is already very useful in medical practice. However it splits the domain of interest from the remaining parts of the network. Most often, crude boundary conditions are used (stress free outlet BCs). Moreover, the living system corresponds to a frosen state, although physiological flows interact with cell lining the interface between fluid and solid. Therefore, computational models of flow in normal and damaged bioconduits require couplings. The talk will illustrate cases for which the nanoscale must be incorporate for future research.

Traditional variation analysis methods, such as Root Sum Square method and Monte Carlo simulation, are not applicable to sheet metal assemblies because of possible part deformation during the assembly process. This paper proposes the use of finite element methods (FEM) in developing mechanistic variation simulation models for deformable sheet metal parts with complex two or three dimensional free form surfaces. Mechanistic variation simulation provides improved analysis by combining engineering structure models and statistical analysis in predicting the assembly variation. Direct Monte Carlo simulation in FEM is very time consuming, because hundreds or thousands of FEM runs are required to obtain a realistic assembly distribution. An alternative method, based on the Method of Influence Coefficients, is developed to improve the computational efficiency, producing improvements by several orders of magnitude. Simulations from both methods yield almost identical results. An example illustrates the developed methods used for evaluating sheet metal assembly variation. The new approaches provide an improved understanding of sheet metal assembly processes.