1,721,089 research outputs found
A Knowledge Based Approach to Flexible Part Design
No full textVirtual prototyping (VP) of complex machines requires the realistic representation of components to perform robust analyses and simulations. In many cases, machines are an assembly of rigid and flexible components. Although modern three-dimensional CAD systems can be considered powerful tools for modelling solids or surfaces representing rigid bodies, they are not adequate to model soft material components, especially a realistic visualisation of physical behaviour. This drawback motivated the present research work. In particular, this paper describes an approach and the related knowledge-based software system (FlexSim) developed to create virtual prototypes facilitating product development in cases of flexible parts like cables, pipes and wires. The resulting VP tool integrates the CAD technology and the dedicated structural simulation methods to automatically model and validate three-dimensional functional sub-groups having flexible parts. The system application is shown on metallic reinforced elastomer hoses used for hydraulic power transmissions. For this purpose, a finite-element approach has been implemented to find hose configurations for given boundary conditions determined by mounting positions. Pipe fittings are selected and automatically assembled and the optimal hose length and its ideal spatial disposition are calculated. Simulations of behaviour allow the rapid optimisation of a solution. The system has been tested on agricultural harvest machines and mining equipment, which widely employ hydraulic transmissions for moving groups of components. As a result, the number of physical prototypes, the lead-time due to the trial-and-error activities and the product development costs can be significantly reduced
Knowledge Based Plants Layout Configuration and Piping Routing
No full textThe design of industrial plants requires managing many geometrical and non geometrical data to reach a satisfactory solution in terms of costs, performance and quality. An approach is presented to support designers in the elicitation and formalization phase of the required knowledge. Then an integral prototypal software application accomplishes layout configuration tasks through a customized graphic wizard. A routing algorithm is presented to automate calculation and modelling of piping and electrical cables respecting design constraints. Cogeneration plant powered by micro gas-turbines has been chosen as test case to evaluate the proposed design method and tool
Context dependent automatic view planning: the inspection of mechanical components
Full text linkLiterature shows how 3D CAD product models can be used as reference in order to manage the verification process by 3D optical scanning systems and the computation of the optimal viewpoints. However, in the mechanical field, a variety of inspection tasks is experienced by engineers involved in the quality control process: GD&T verification, production phases control such as sheet metal cutting, evaluation of aesthetic appearance of parts, global shape deformation measurement and specific point deviations assessment. This leads to the necessity of flexible view planning approaches which adapt to the specificity of the required inspection task. The present work targets the development of a comprehensive view planning approach in which several algorithmic options are triggered by the product features to be inspected. Algorithms have been implemented in a prototypal software system which has been experimented as an off-line application to provide inputs to a multi-axis Degree of Freedom (DoF) robot arm mounting an optical 3D scanner. Two test cases from die casting and automotive fields are presented. They show the computation of acquisition poses in a suitable sequence and efficiency in the obtained results
How Product Designer Can Manage the Quality Control Process
No full textThe right prescription of the GD&T tolerances has a meaningful impact on the whole product development process. The designer has to be able to take rapid decisions in order to minimize cost and maximize quality. The decision-making process has to be supported by proper data usually generated by the design department. The aim of this research work is the centralization of product development phases into design stage. In particular an approach is proposed in order to transfer the whole tolerancing activities from manufacturing shop floor to product design department. The approach is concretized in a set of software and hardware tools able to: simulate and plan the GD&T quality control, manage the measurement systems, analyze the acquired data and improve the tolerance prescriptions. A set of metrics has been identified in order to evaluate advantages and limitations of proposed approach
Direct fabrication through electron beam melting technology of custom cranial implants designed in a phantom based haptic
Full text linkRepairing critical human skull injuries requires the production and use of customized cranial implants and involves the integration of computer aided design and manufacturing (CAD and CAM). The main causes for large cranial defects are trauma, cranial tumors, infected craniotomy bone flaps and external neurosurgical decompression. The success of reconstructive cranial surgery depends upon: the preoperative evaluation of the defect, the design and manufacturing of the implant, and the skill of the operating surgeon. Cranial implant design is usually carried out manually using CAD although this process is very time-consuming and the quality of the end product depends wholly upon the skill of the operator. This paper presents an alternative automated method for the design of custom-made cranial plates in a PHANToM ®-based haptic environment, and their direct fabrication in biocompatible metal using electron beam melting (EBM) technology
Improving the link between computer assisted design and configuration tools for the design of mechanical products
No full textThe competitive market forces companies to offer tailored products to meet specific customer needs. To avoid wasting time, design efforts generally address the configuration of existing solutions, without producing substantial design modifications. Configuration tools are used to achieve customized products starting from a common platform.
Many approaches have been successfully proposed in literature to configure products. However, in the mechanical field they need further investigation in order to be efficiently linked to Computer-Aided Design technologies. Research is focused on tools and methods to automatically produce geometrical models and improve the flexibility of the continuous product updating process.
In this context, this paper aims to combine product configuration approaches with design automation techniques in order to support design activities of products to fulfil specific requirements. The approach is based on entities called Configurable Virtual Prototypes (CVP). Three different domains are managed and connected via CVP: Product Specifications, Geometrical Data and Product Knowledge. In particular, geometry recognition rules are used to identify the parameterization of parts and the assembly mating constraints.
The approach is exemplified through an industrial case study where a tool has been developed on the basis of the described method. Advantages of the system are shown in terms of achieved product configuration efficiency
Innovative Technologies to Support Positioning of Corrective Appliances in Orthodontic Treatments
No full textTime Compression Technologies (TCT) are strongly widening their application fields, particularly in not traditional sectors, such as archaeology, jewellery, architecture and so on. The biomedical domain, especially orthodontics, is one of the most interesting. The design and positioning processes of corrective dental appliances consist of phases which can strongly benefit from Reverse Engineering (RE) and Rapid Prototyping (RP) techniques in terms of quality and time reduction. In these last years new systems have been developed to support the operator work but, unfortunately these technologies are still not largely used in orthodontic laboratories. In this context, the present paper, facing the problem of critical activities identification in corrective treatments orthodontic practice, proposes a low cost and easy to use technical solution in order to support orthodontists for a rapid and accurate positioning of vestibular and lingual brackets. In particular a new CAD (Computer Aided Design) software system to support the dental appliances design process has been implemented
A Finite Element Method to support the materials selection phase during the insole design process
No full textPurpose: The paper aims to define a method to support the materials selection phase during the insole design process. The proposed scientific approach is pursued adopting a finite element method to simulate the mechanical behaviour for combinations of materials to create customized insoles. The paper presents also two processes, one to design the custom made insole and the other to select the insole materials combinations with the aim to uniform the foot plantar pressure.
Method: The insole design and the materials selection processes are based on the use of software tools to manage the materials properties, in order to make them as scientific as possible. A Finite Element Method is used to calculate the stress-strain relationships of a custom combination of multiple layers of materials. The contextualization of this method into the insole design process allows the proposed idea to be successfully implemented.
Result: The error committed by the Materials Combinations Simulator has been verified with a large set of materials (EVA, PU and rubber). Experimental tests have been performed to evaluate the deviation with the results of the simulation model, highlighting an error less than 10%.
Discussion & Conclusion: This work is a step toward a more scientific design process for custom made insoles. The possibility to simulate the mechanical behaviour of a combination of multiple materials lead to the elimination of the physical tests. The integration of the proposed Materials Combinations Simulator system with an Insole Design software tool will represents a further innovation respect the state of the ar
Multi-Level Representation for Supporting the Conceptual Design Phase of Modular Products
No full textDesigning a new product, in most cases, means a modification of an existing one. Both adopting known solutions in different products, that inserting new technological processes into a consolidated context, the most design effort must be dedicated to the early evaluation of the impact of needed engineering changes to achieve the final result, in terms of cost, quality and time. Such activity is particularly strategic in the modular product development. The aim of our research work is to develop a method and the related tools that enable designers to easily represent the product platform, to structure the relations between modules defined at different levels of detail and, hence, to simulate, analyze and evaluate the modifications impact during the new product variant definition phase. A multi-level product structure able to represent the product informative content at different levels of detail is presented
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