Community Research and Development Information Service - CORDIS

Final Report Summary - PRO-STONE (Eco-efficient and high productive stone processing by Multifunctional Materials)

The 'Eco-efficient and high productive stone processing by multifunctional materials' (PRO-STONE) project aimed at creating new knowledge in the area of 'Shape memory alloys' (SMA) technology and integrates it in a knowledge management infrastructure to facilitate and support design and validation of new machinery concepts by the large and scattered European community of stone SMEs. It also aimed at grouping a large number of European IAGs leaded by the European Federation of stone industries with the major goal of solving specific needs, improving the technological status of the stone SMEs and transforming this rather traditional and regionalised sector into a modern, competitive and high added value industry.

Figures on world stone trade show that the market share of the EU countries has been decreasing over the last few years in favour of relatively new Far East and Southern American countries. The main reasons for this is that the sector has not made any significant technological progress and operations are faced by low productivity and efficiency, fluctuation in the quality, huge quantities of waste, high energy consumption and critical safety for the workers. The development of environmentally friendlier technologies is indeed an issue, considering that stone is a non-renewable resource. Furthermore the European equipment manufacturers have been made more aware of safety and health (noise, dust, etc.) of the operators through recent stringent regulations that requires for alternative technologies. To address these issues scattered attempts have been registered in Europe to apply knowledge-based multifunctional materials in stone tools and equipment. The most promising are based on the application of SMAs. Several concepts have been developed by our core group SMEs based on this novel material. However, the available results show that macro-scale SMA elements have a lower level of reliability and performance reproducibility with respect to micro-scale SMA devices so far applied in the medical sector.

The overall technological objectives of the PRO-STONE project were:
- to fully characterise at least ten ornamental stone types - such as granite, gabbro, quartzite, marble, and limestone - to correlate parameters as stone macro hardness, stone Young's modulus, fracture toughness, critical stress intensity factor, fracture strength, statistical distribution and stone abrasiveness to equipment parameters such as the generated forces, the energy consumption and the tool wear ratio as well as to model the quasi-static propagation of cracks and fractures in stone blocks and the stone-tool interaction under dynamic processing conditions;
- to scientifically characterise the fatigue behaviour (fatigue strength and cycles) of four SMA families like Ni-Ti, Ni-Ti-Cu, Cu-Zn-Al, and Ni-Mn-Ga (this latter ferromagnetic, FSMAs) alloys, and at least ten different geometries as well as different representative dimensions thereof, subject to multiaxial monotonic or cyclic loading as well as large forces as the ones experienced in bulky applications like stone extraction and processing in order to be able to guarantee repeatable and reliable performances as well as a predictable lifetime for multifunctional components to be widely integrated into novel high performance machinery and tools;
- to extensively analyse and characterise ten different joint designs and methods and other connections and bonds both in the case SMA-SMA and SMA-stainless steel connections and their mechanical and fatigue behaviour;
- to develop numerical models able to describe the large forces and displacements that can be generated due to the shape memory effect of the selected representative SMA types and SMA component geometries as well as complex arrays of elementary geometries to be used as actuators on the basis of the performed testing campaigns;
- to model the superelastic behaviour in large diameter wires or other mechanical components subject to cyclic loading over at least 1000 cycles for Ni-Ti, Ni-Ti-Cu and Cu-Zn-Al families, by integrating constitutive models able to simulate the strain energy absorption mechanism;
- to analyse different types of actuation mechanisms which are case by case applicable to different SMA types and geometries in order to fully understand and characterise the actuation-related non-homogeneous deformations that occur in specimens of different geometries and dimensions, thus to model deformations and find out relations that allow optimising actuation forces or displacements versus applied actuation energy and modes. Performance degradation phenomena will be investigated as well in order to guarantee the proper reliability of the SMA-based component. Stress sensing properties will be as well characterised in order to evaluate the potential of developing integrated SMA-based sensoractuator smart components or self-diagnostic features to the machines;
- to develop an e-learning module dealing with SMAs knowledge, basic principles and applications to stimulate the take up of knowledge on SMAs by SMEs. The e-learning module will be developed with the objective to transfer basic principles of SMA technology as well as to give examples of applications in the stone sector to SMEs, so as to stimulate the generation of new SMA-based ideas and applications within the stone processing industry. For this purpose, the e-learning module will avail itself of an interactive e-training environment to identify the user knowledge needs and lead him to the different training modules;
- to develop a design support system to assist SMEs in the development and validation of new SMA-based concepts. The design support system will be made available through a knowledge web platform and will guide users in the validation and preliminary design of SMA-based concepts, through the use of the knowledge available in different knowledge based repositories, and specifically the machines knowledge based repository, the SMAs knowledge based repository, the stones knowledge based repository, as well as through the use of numerical models. Repositories will contain technical data on SMA materials/components, stone mechanics and stone quarrying and processing machinery/tools to be made available to the user through guided and focused queries to the design support system.

The work packages that structured the project and their objectives were:

WP 1: Critical analysis of stone machinery, equipments and opportunities
Objectives: Critical review of machines and tools for stone quarrying and processing, analysis of the working principles of the machines/tools and identification of representative and recurrent mechanical component geometries and identification of potential application opportunities.

WP 2: Stone characterisation, study of fracture behaviour and stone-tool interaction
Objectives: Extensive characterisation of ornamental stones to assess the material's characteristics that allow the evaluation of stone mechanical properties and fracture behaviour, evaluation and modelling of quasi-static propagation of cracks in stone blocks (fracture process) and evaluation and modelling of stone-tool interactions under dynamic processing conditions

WP 3: SMA components: joining and actuation strategies
Objectives: Setting up of a technical information system on SMAs through an extensive literature review. Definition of representative testing conditions and setup of experimental equipment for SMA components: testing, joining modes characterisation and actuation modes testing. Characterisation and modelling of generated forces and displacements for the selected representative SMA component geometries and complex arrays of elementary geometries to be used as actuators. Identification and characterisation of SMA-SMA or SMA-stainless steel joining modes and testing of fatigue failure thereof. Identification of all applicable actuation strategies, testing of actuation modes, characterisation and FE modelling of actuation-related non-homogeneous deformations; identification of SMA strain sensing properties.

WP 4: Development of the knowledge web portal and design support system
Objectives: Design and setup of knowledge web portal architecture and common services, development of an e-training section for demonstration and training aimed at stimulation of SMA applications in stone machinery, construction of the knowledge based repositories and development of the design support system through the integration of models.

WP 5: Validation of the design support system
Objectives: Prototyping of demonstrators according to the identified application opportunities, testing of the identified application opportunities and validation of the design support system.

WP 6: Exploitation and dissemination activities
Objectives: Development of an effective securing of knowledge generated in the project, development of an effective dissemination and exploitation of the project results among and beyond the project partners.

WP 7: Training activities
Objectives: Development of appropriate and effective courseware, training material and training methodology to ensure an effective transfer of knowledge to SMEs belonging to the stone sector.

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