Mechanical Engineering

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Research Topic Summary.

Adaptive composite structures represent a significant advancement in engineering, holding the potential to create more efficient, sustainable, and safer systems across various industries. By incorporating smart materials, sensors, and actuators, these structures can dynamically respond to environmental changes, optimizing performance while minimizing energy consumption and reducing maintenance requirements. The scientific problems at the core of this topic lie in selecting suitable smart materials, modelling their performance under different conditions, integrating them into composite structures, and ensuring their long-term durability, responsiveness, and efficiency in real-world applications.

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Research Topic Summary.

Drawing inspiration from nature, specifically biological systems, offers a promising approach to developing biomedical systems that interact effectively with the human body and can perform tasks such as monitoring and stimulation. The primary focus of the current research is to create an active microhydraulic-actuated system with an integrated sensing function. This is accomplished by combining a flexible microhydraulic element with a piezo-polymer, resulting in a functional component capable of flexural movements and integrated sensing, along with a theoretical framework for its design.

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Research Topic Summary.

This research topic is intended for the amenities and technologies conditioning the further development of hybrid natural fiber-based biocomposites for lightweight body panels in automotive applications, flexible sensors, advanced electronic devices, solar cells and etc. It is planned to develop natural fiber reinforced bio matrix-based hybrid composites in the presence of nanoparticles (bio-based) based on the rule of hybridization concept. To acquire superior mechanical properties, hybrid composites are fabricated by joining two or more different natural fibers with similar chemical composition and mechanical properties under the same matrix material, evaluating its, mechanical, morphological, wettability, chemical, and dynamic properties. Results of this research will be substantial for the expansion of a new generation of eco-friendly hybrid composites.

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Research Topic Summary.

One of the modern metal products industries is the welding of metal parts. In addition to traditional welds used in the past: electric arc, plasma gas flow, conventional spot welding and many other welds, new, progressive welding methods are increasingly being used: laser, friction welding. Welding using these methods can be done more precisely, more efficiently, it is possible to weld materials that are difficult or even impossible to weld in traditional ways. The most important welding parameter is the seam reliability. The thread must meet the operational design requirements. It is affected by the metal composition, welding method and mode. When welding with conventional technology, good weldability is considered when the joint strength obtained is equal to the strength of the base metal. The purpose of the study is to make experimental investigation and numerical simulation of Friction Stir Welding (FSW) process of dissimilar materials and their alloys.

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Research Topic Summary.

Surface engineering plays a critical role in improving the physical, chemical, and functional properties of materials to meet the needs of a variety of applications, from industrial machinery to biological implants. Modification of surface characteristics can significantly improve performance in harsh environments, such as increased wear resistance, corrosion protection, and greater biocompatibility. This study will explore various surface modification techniques, with a particular focus on coating methods (e.g., thermal spraying, PVD, CVD) and surface texturing techniques (e.g., laser surface texturing, micromachining).

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Research Topic Summary.

The structural integrity of components of environmentally hazardous enterprises must be ensured under normal operating conditions and in hazardous conditions. Nuclear power plants, thermal power plants, chemical industry companies, oil industry companies, gas pipelines, heating networks, etc. can be classified as hazardous. Metal structures and pipelines in the above-mentioned companies may cause metal degradation due to higher temperature, more aggressive working environment exposure, and thus their integrity will be vulnerable. One of the main mechanisms of degradation is metal fatigue, which may lead to structural fracture. The purpose of the research is to investigate the fatigue and its cyclic properties of metals used in energetic objects by applying multiaxial loads and determining the relationships between these types of load deformation and fracture properties.

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Research Topic Summary.

Development of multi-material FDM for 3D printing of piezoelectric and conductive materials is a key driver of several emerging disruptive fields such as 4D printing of sensory structures, additively manufactured mechatronics components with structure-embedded strain sensors and energy harvesters (for load sensing and damage detection (SHM)). Efficient multi-material FDM workflows are needed for the single-process (all-in-one) 3D printing of sensory composite components with diverse functional layers (piezoelectric, conductive, dielectric, etc.). To achieve scalability and environmental sustainability, thermoplastic composites should be fabricated in a solvent-free workflow by using melt extrusion of the composite filaments containing piezoelectric or conductive fillers. The durability of the sensory composites is imperative in performance-critical applications such as lightweight air-/spacecraft or medtech components where SHM is important. The FDM workflow should be integrated with auxiliary thermal and/or electrical processing operations (e.g. applying electrical field) to enhance the electromechanical sensitivity or harvested power output. The implemented hybrid additive manufacturing (HAM) workflow should provide more design freedom to enable more cost-effective small-batch fabrication of highly customizable and resilient multifunctional components with structure-embedded sensing and energy harvesting properties. The aim of the PhD project is to implement a multi-material HAM workflow to print sensory structures by using custom-made electroactive composite filaments. A PhD student will mainly work on: i) extrusion and characterization of composite filaments with tailored electroactive properties; ii) integration of multi-material FDM with performance-enhancing thermal and/or electrical processing operations; iii) simulation-based design, prototyping and performance testing of 3D printed electroactive composites and sensory structures.

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Research Topic Summary.

The efficiency of methods and technologies of Industrial Maintenance 4.0/5.0 depends on the ability to integrate knowledge from different fields of science and technology to develop solutions than can be easily adapted in different companies. The aim of this research is to create a multi-parametric optimization method that integrates technical diagnostics, big data analytics and expert decision support tools, enabling the optimization of technical maintenance activities in various business sectors.

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Research Topic Summary.

Scientific research on this topic can be carried out not only by masters of mechanical engineering, but also by masters of mechatronics, automation, electrical or informatics engineering. The idea of the proposed topic: to design a mechatronic device - a controlled shoulder joint trainer. The novelty and originality of the idea and experience in the field of the research is that is offered the solution to develop and test a shoulder joint trainer that is user-friendly, easily adaptively controlled using an electromyography (EMG) model. EMG is a diagnostic procedure that aims to assess the condition of nerves, muscles and the nerve cells that control them (motor neurons). EMG will be used to assess the electrical activity of the muscles (i.e., the total action potential) on the skin surface, both when the muscles are relaxed and when they tightened at different intensities. Upon detection of movement from the processed EMG signal, a control signal will be generated, which will be transmitted to the executing components of the trainer so that the corresponding movement of the trainer can be performed together with the movement of the shoulder joint.

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Research Topic Summary.

Complex geometric shapes and details of various purpose objects and figures are rapidly increasing nowadays in various fields of industry and everyday life. Despite the fact, that modern computer hardware and software greatly facilitates the creation of such objects/shapes during the design phase, the actual production of such objects is very complicated and expensive. For this reason, the incremental forming of sheets, mainly made from metals, is being investigated and used nowadays. This machining method allows a significant reduction in time and cost. Among other things, the incremental sheet forming allows the production of objects/shapes of extremely complex geometric shape which would be very difficult or even impossible to produce by traditional methods. The aim of doctoral research is to develop and investigate a hybrid additive manufacturing technology based on 3D printing and robotised incremental sheet forming (ISF) of multi-material/functional structures (i.e. biocompatible, antibacterial, aesthetically personalized, static-dissipative, electrically or thermally conductive, etc.), which will be designed via AI-assisted workflow for applications in health devices (e.g. cranial implants, personal protective equipment (shields, etc.) and transport vehicles (e.g. protective or aerodynamic components, etc.).

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Research Topic Summary.

Monitoring and assessing the structural integrity of composite materials is essential for economic and safety reasons. The research would aim to improve structural health monitoring (SHM) techniques for composite structures by integrating the concept of a Digital Twin. The developed system intent to analyze the mechanical response of the physical structure and assess the health of the structure. The main objective is to develop a system in which Digital Twins, together with integrated sensors and data analysis techniques, allow the monitoring and prediction of the health of composite structures. The research would involve the development of validated finite element model of a selected composite structure, including material characterisation and calibration of the material model, in the laboratory. The finite element model will allow to accurately predict the elastic behaviour of the composite material and the effect of damage on the mechanical response of the structure. Ful field displacement and strain measurements from a 3D digital image correlation system will be utilised to calibrate and validate the numerical models. The same measurements would be adopted to test the developed structural health monitoring system. The different damage patterns (different positions, sizes and shapes) generated in the finite element model of the composite structure will be used to create a virtual database of mechanical response and used to train the surrogate mathematical model. The surrogate deformation maps of the digital twins under different loading conditions and damage will be aplied for damage diagnosis and condition monitoring of the composite structure.

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Research Topic Summary.

More sustainable manufacturing of next-generation functional/smart composite materials based on nature-derived polymers is a prerequisite for development of environmentally safe (multi)functional components, which will be increasingly used within the emerging fields of green or degradable/transient (bio)electronics and (bio)mechatronics. In particular, thermoplastic bio-based smart composites (e.g. bacteria-derived biopolymers with eco-friendly fillers) are needed for extrusion-based additive manufacturing of various smart eco-structures/devices. They should have negligible negative impact on ecosystems/health and should possess advanced functional/smart properties such as electrical conductivity, sensing, energy harvesting, etc. Applications are diverse and include limited-lifespan electronic devices (e.g. disposable sensors for environmental monitoring), sensorized compostable consumer products, diagnostic/therapeutic healthtech devices, resorbable implants/scaffolds, etc. To ensure cost-effectiveness and environmental sustainability it is important to further develop and validate melt-based manufacturing processes for more eco-friendly (e.g. solvent-free), more efficient and industrially scalable production of extrudable bio-based composites. The main aim of the PhD project is to manufacture a biopolymer-based functional/smart composite material using hot melt extrusion and to demonstrate the use of extruded filaments/granules in 3D printing a multifunctional eco-device (e.g. limited-lifespan disposable sensor). A PhD student will work at KTU Institute of Mechatronics on: i) demonstration and validation of filament extrusion process for a specific type of bio-based functional/smart composite; ii) characterization of mechanical, physicochemical and relevant functional properties of extruded and printed samples; iii) simulation-driven design, rapid prototyping and performance testing of printed prototypes of a multifunctional eco-device.

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Research Topic Summary.

Additive manufacturing (AM) known as 3D printing is a digital manufacturing process dedicated for the production of complex geometry parts. Growing interest in AM is related to the main benefits of technology: reduction of waste, design flexibility, minimization of product delivery time and better process performance. Another important point is that the variety of materials is also constantly increasing and opening new possibilities for applications. Materials, starting from polymers, metals, ceramics, and composites are widely used in AM technologies, however sustainability aspect should be considered too, especially when talking about composites. This research will focus on the development of the AM process for production of composites reinforced with natural fibers. The main benefit of natural fibers is environmental friendliness due to material renewability and biodegradability. The combination of natural fibers and biopolymers will allow to produce structural parts with predictable mechanical performance and behavior. Moreover, AM of natural composites will help to minimize process impact on environment and reduce CO2 level.