Applied Mechanics and Materials Vol. 657

Abstract: The article presents a reflection on the definition of the feature, which enabled the development of feature-based method for modeling of composite structural components. The need for defining feature is a direct result of the ambiguity of statements or narrow definitions and their applications. So far are well developed feature, which are used in process design (CAD) - geometric feature, design feature and in the process of manufacturing (CAM) - Technology feature, and also focused on functionality (CAE - motion simulation) functional feature. The feature representation of a fully functioning feature-based system that does the aggregation of information about the structure of a construction object made from layered composites.. This approach is based on a single, independent feature representation that can be used for design, finite element analysis, technology process planning. The paper describes the main approach to the engineering analysis with the use of FEM and a convenient method of simplifying the geometry of the model and the composition of the composite. Also discussed are possible extensions to features to enhance the finite element meshing process.

Abstract: To re-create a 3D parametrical environment it was used a CAD software which permits to define complex models. First, there were defined the main bone components as femur, tibia and pelvis by using the CT images. The contours of the CT images were transferred to CAD environment where, step by step, and section by section, the virtual bones were defined. The model of the pelvis and of the lower limbs during a virtual walking was recomposed by using kinematic parameters determined by filming the human subject. In this case the entire behavior of each bone component was determined, including that of the tibia. The variations of force and torque which auctioned over the tibia were determined and applied to the fractured tibia with the new models of nails.

Abstract: Expansion joints are used in installations where axial or angular significant changes occur due to operating conditions: differences temperature, arching, vibration etc. Expansion compensation will take over the pipe stresses, preventing so their destruction. Lenticular compensators take pipe thermal expansions; metal compensators are use for take axial, lateral or angular displacement. This paper presents information regarding the lenticular compensators and calculation procedure of their geometrical characteristics, mainly the number of elements that composed them. An automatic calculation program ”CCRT - Comp Lent” (computing pipeline heating systems – lenticular compensation) was developed based on fundamental concepts in mechanical calculation of pipes and lenticular compensators. The algorithm of this program is based on determining the pipeline expansion, the total deformation and the number of the compensation required.

Abstract: The subject of this paper permits the cooperation between many researchers which activate in different fields, which have the capacity to develop informational methods and technologies to solve difficult problems given by the complexity of the scientifically target. Using computer-aided design (CAD) and dynamic simulation programs was developed a virtual model of the cervical human spine that includes the main muscle groups simulated by springs with dynamic parameters, nonlinear and variable. Were studied the main types of movements (displacements) lateral bending (left-right) and flexion-extension movements.

Abstract: Checking the symmetry of a Formula One (F1) car nose requires the measurement and inspection of complex surfaces and raises a number of challenges both in terms of the equipment used and the measurement strategy. Verifying the symmetry allows the identification of the asymmetrical areas regarding the critical aerodynamic elements of F1 car nose. This paper presents three methods to check the symmetry of a F1 car nose and to determine the deviation using symmetry points (by points measuring) in plane using 2D scanned profiles and 3D laser scanned surfaces. In order to acquire the symmetry points, and to scan the profiles and the surfaces, a state of the art multi-sensor CMM (Coordinated Measuring Machine) has been used and the data has been processed in CATIA V5.

Abstract: Nowadays the world is facing an increasingly traffic, especially in the road. In order to short the distances and cross various road areas, road tunnels are built frequently and longest as possible. One of the greatest emergency situations that can occur in road tunnels, is represented by fire, involving all conditions relating to the nature and density of combustible materials existing, smoke, toxic gases and the combustion debris from fire fighting and action in order to minimize the negative consequences of it. Also, road tunnels represent semi-closed and closed spaces, with high fire risk, so no easy fire safety management opportunities can be used. Road tunnels can be framed in the category above mentioned, being exposed to a high traffic, because most of them are 20-30 years old and were built for the traffic estimated of those times. A simulation using Pyrosim software is based on the physical model in which one electrical fault accident involving a car appear. The accident, consisting in a fire event at one stationary car, is modeled at 1.5 m height. Considering an electrical fault followed by a fire, temperature and smoke spreading depending on time in this tunnel were obtained. Also, sprinklers have been used in the simulation time, in order to give an accurate firefighting simulation. There were obtained important values which allow us to realize an appropriate impact on the event in aim of minimizing the time for a promptly intervention and to limit the damages.

Abstract: The current work demonstrates a feasibility study on the generation of a copy, having a highly complex geometry, of a Greek paleontological find utilising reverse engineering and low-cost rapid prototyping techniques. A part of the jaw bone of a cave bear (Ursus spelaeus) that lived during the Pleistocene and became extinct about 10,000 years ago was digitized using a three-dimensional laser scanner. The resulting point-cloud of the scans was treated with a series of advanced software for the creation of surfaces and ultimately for a digital model. The generated model was three-dimensionally built by the aid of a Fused Deposition Modeling (FDM) apparatus. An analytical methodology is presented revealing the step by step approach from the scanning to the prototyping. It is believed that a variety of interested parties could benefit from such an analytical approach, including, production engineers, three-dimensional CAD users and designers, paleontologists and museum curators.

Abstract: In this paper a method that allows the generation of complex trajectories using a RRTRRR robotic system (with five rotation modules and a translation module) is presented. The method is based on the decoupling between the positioning function and the orientation function of the tool frame (O_Tx_Ty_Tz_T) attached to the robot gripper. The method permits to determine all the solutions corresponding to the robot coordinates that allow obtaining the movement of the tool frame with imposed position and orientation parameters. Finally, some simulation results are presented in the case when O_T is moving along a parabolic trajectory with an imposed orientation of the tool frame.

Abstract: Real-time information feed describing the state of production system is the key to successful management of any company, because up-to-date information is necessary basis for decision making in company operating on globalised market. Data describing the state of the production system should be collected in the manufacturing system, pre-processed, interpreted, filtered, archived and finally, either used in IT systems supporting company management (MES, ERP), or directly presented to crew and managers responsible for specific areas of interest. Possibility of data acquisition in companies strongly depends on specific of branch of industry, technological processes automation level, number of operations performed manually, type of production, etc. Acquisition of data on state of the production system should be carried-on automatically, without involvement of workers. This paper presents overall description of issues of data acquisition in company, proposed Manufacturing Information Acquisition System (MIAS) and the case study of data acquisition in company leading continuous, automated production processes Central Wastewater Treatment Plant (WWTP) in Gliwice, Poland.

Abstract: Conception of certain mechanical systems used in medical robotics is limited due to the ranges of allowed values for different design factors: weight, volume, quality, safety, and cost. It was identified the need to design these products and to simplify/optimize the concept, so that, with minimal changes, can be created families like products with the same functions but with different technical characteristics. Still, there are ways to use modern instruments parametrization design, finite element analysis of dynamic behavior of a poly-articulated miniature robotic arm. The research consists in the development of a methodology applied to result concrete data relating to the design of the poly-articulated mechanical system, simulation and validation of geometric patterns models predetermined of a FEM analysis. Also, the obtained information during tests will be used to determine the final configuration of the optimized concept.