Approaches for the Simulation of Deformable Objects in Manufacturing Systems

The validation of control software using methods of Virtual Commissioning (VC), with its origin in the field of machine tools, gains more and more importance in other application areas like process engineering or material-flow-intensive production systems. Especially because of the increasing complexity of technical systems the validation of the control software quality is a major challenge in production technology. To reduce the efforts of modeling and to increase the value of simulation results, a so-called physically model is integrated in the VC. Currently the physically based Virtual Commissioning is restricted to rigid body simulation objects. In this publication new methods for the simulation of deformable objects are shown and validated in an industrial context. Therefore the hybridization of existing simulation methods from computer science using so called physic engines is introduced as a method that simplifies the description of complex simulation objects by adapting well known simulation models. The new approach is comparable to a mixture of a multi body simulation and a real-time finite element simulation

Looking beyond appearances: a multi-analytical approach on the prehistoric clay weights

AbstractIn this paper we analyzed a batch of 64 clay weights from three archaeological sites located in Romania (Gumelniţa, Măgura-Jilava, and Sultana) that belong to Kodjadermen-Gumelniţa-Karanovo VI cultural complex (4600–3900 cal. BC). Our approach includes an interdisciplinary investigation based on technological analysis, experimental archaeology, and X-ray CT scans coupled with statistical analysis. This investigation has a high potential to reveal relevant information regarding the technological background (e.g., inclusion, voids, temper, etc.), manufacturing stages (e.g., modeling, shaping, kneading, etc.), or transformation processes (e.g., drying and firing vs. weight and size modification) in order to identify, explain and understand thechaîne operatoirefor this type of artefacts. Moreover, correlation of the results with the experimental archaeology could offer an integrative interpretation about the material culture of past humans and its multiple meanings, but also critical information about the multiple dimensions of manufacture for these objects (e.g., time, effort, physical–chemical processes, etc.). The multi-analytical approach proposed here also includes a comparative study of technological aspects of these clay weights across the three archaeological sites investigated, as well as the experimental replicas

A continues multi-material toolpath planning for tissue scaffolds with hollowed features

This paper presents a new multi-material based toolpath planning methodology for porous tissue scaffolds with multiple hollowed features. Ruled surface with hollowed features generated in our earlier work is used to develop toolpath planning. Ruling lines are reoriented to enable continuous and uniform size multi-material printing through them in two steps. Firstly, all ruling lines are matched and connected to eliminate start and stops during printing. Then, regions with high number of ruling lines are relaxed using a relaxation technique to eliminate over deposition. A novel layer-by-layer deposition process is progressed in two consecutive layers: The first layer with hollow shape based zigzag pattern and the next layer with spiral pattern deposition. Heterogeneous material properties are mapped based on the parametric distances from the hollow features

SFF-Oriented Modeling and Process Planning of Functionally Graded Materials Using a Novel Equal Distance Offset Approach

This paper deals with the modeling and process planning of solid freeform fabrication (SFF) of 3D functionally graded materials (FGMs). A novel approach of representation and process planning of FGMs, termed as equal distance offset (EDO), is developed. In EDO, a neutral arbitrary 3D CAD model is adaptively sliced into a series of 2D layers. Within each layer, 2D material gradients are designed and represented via dividing the 2D shape into several sub-regions enclosed by iso-composition contours. If needed, the material composition gradient within each of sub-regions can be further determined by applying the equal distance offset algorithm to each sub-region. Using this approach, an arbitrary-shaped 3D FGM object with linear or non-linear composition gradients can be represented and fabricated via suitable SFF machines.Mechanical Engineerin

Optimized normal and distance matching for heterogeneous object modeling

This paper presents a new optimization methodology of material blending for heterogeneous object modeling by matching the material governing features for designing a heterogeneous object. The proposed method establishes point-to-point correspondence represented by a set of connecting lines between two material directrices. To blend the material features between the directrices, a heuristic optimization method developed with the objective is to maximize the sum of the inner products of the unit normals at the end points of the connecting lines and minimize the sum of the lengths of connecting lines. The geometric features with material information are matched to generate non-self-intersecting and non-twisted connecting surfaces. By subdividing the connecting lines into equal number of segments, a series of intermediate piecewise curves are generated to represent the material metamorphosis between the governing material features. Alternatively, a dynamic programming approach developed in our earlier work is presented for comparison purposes. Result and computational efficiency of the proposed heuristic method is also compared with earlier techniques in the literature. Computer interface implementation and illustrative examples are also presented in this paper

From 3D Models to 3D Prints: an Overview of the Processing Pipeline

Due to the wide diffusion of 3D printing technologies, geometric algorithms for Additive Manufacturing are being invented at an impressive speed. Each single step, in particular along the Process Planning pipeline, can now count on dozens of methods that prepare the 3D model for fabrication, while analysing and optimizing geometry and machine instructions for various objectives. This report provides a classification of this huge state of the art, and elicits the relation between each single algorithm and a list of desirable objectives during Process Planning. The objectives themselves are listed and discussed, along with possible needs for tradeoffs. Additive Manufacturing technologies are broadly categorized to explicitly relate classes of devices and supported features. Finally, this report offers an analysis of the state of the art while discussing open and challenging problems from both an academic and an industrial perspective.Comment: European Union (EU); Horizon 2020; H2020-FoF-2015; RIA - Research and Innovation action; Grant agreement N. 68044

Multi-Object Tracking with Interacting Vehicles and Road Map Information

In many applications, tracking of multiple objects is crucial for a perception of the current environment. Most of the present multi-object tracking algorithms assume that objects move independently regarding other dynamic objects as well as the static environment. Since in many traffic situations objects interact with each other and in addition there are restrictions due to drivable areas, the assumption of an independent object motion is not fulfilled. This paper proposes an approach adapting a multi-object tracking system to model interaction between vehicles, and the current road geometry. Therefore, the prediction step of a Labeled Multi-Bernoulli filter is extended to facilitate modeling interaction between objects using the Intelligent Driver Model. Furthermore, to consider road map information, an approximation of a highly precise road map is used. The results show that in scenarios where the assumption of a standard motion model is violated, the tracking system adapted with the proposed method achieves higher accuracy and robustness in its track estimations