This chapter presents the cellular materials and their composites in general and then mostly concentrates on the particularities of advanced pore morphology (APM) foam. Single metallic APM spheres and their mechanical properties are characterized with experimental testing and computational simulations, providing the basic properties and knowledge for an efficient design of composite APM foam structures. The chapter also presents APM foam elements molded with epoxy matrix, resulting in composite structures of different morphology types. One of the most important areas for the future application of cellular materials is in the automotive industry, where their high impact energy absorption through deformation is of crucial importance for increasing the passive safety of vehicles. Results of experimental testing of single APM foam elements are given for quasi-static and dynamic loading conditions.
B.04 Guest lecture
COBISS.SI-ID: 17291030Dr. Polona Dobnik Dubrovski was a member of the scientific committee of the international conference ICETT 2014 Jalandhar. This is evident from the organiser's website.
D.03 Membership in foreign/international boards/committees
vabljeno predavbanje na 49th meeting of the Committee on High-energy-rate forming, JSTP, at the Kumamoto University, Institute of Pulsed Power Science, Japan, Friday 27th June 2014.
B.04 Guest lecture
COBISS.SI-ID: 18114070The fatigue analysis of working rolls in hot strip mills is presented in this doctoral thesis. Besides the determination of the high cycle fatigue, a lot of other experimental work was performed. Chemical composition with microstructure before and after special heat treatment is given. Also hardness distribution in depth through the whole working layer is presented. Monotonic tensile and compressive tests were done at different temperatures of the specimens, which correspond to the real situation in the rolling gap. Besides tensile and compressive tests, also bending and Charpy impact toughness tests were done. Fracture mechanics parameters and fatigue crack growth analysis was experimentally determined and moreover, a complete fracture investigation was performed by using scanning electron microscope. At the end of the thesis a result of wear is shown, where special testing device was developed for this purpose.
D.09 Tutoring for postgraduate students
COBISS.SI-ID: 18008598Award: special award - 12th Trimo research award for year 2014, Trimo Trebnje A significant part of manual work is still done using hand-tools. Therefore, an ergonomic design of a tool-handle might be crucial for preventing upper-extremity musculoskeletal disorders. Current design methods consider cylindrical handles and provide guidelines for determining optimal diameters to increase performance, comfort and thus minimizing the risk of acute and cumulative traumatic disorders. However, the shape of the handle and the handle's materials have not been investigated in detail yet, which could additionally improve the handles' ergonomics. In order to overcome the limitations of correct shape determination, we have developed an anatomically accurate static virtual human-hand model in its optimal power grasp posture for direct tool-handle modelling based on interdisciplinary methods using medical imaging. To overcome the limitations regarding the correct tool-handle material determination, we have utilized a finite-element method for simulating human fingertip whilst grasping different tool-handle materials. The results have shown that the tool-handle based on the developed virtual human-hand model provides significantly higher contact area and comfort rating compared to the cylindrical handles. With higher contact area and anatomical shape of the handle, extensive deformation of the soft tissue can be avoided, thus preventing excessive load on the hand. Numerical tests have shown that conventional tool-handle materials do not lower the contact pressure. The proposed hyper-elastic foam materials, which take into account the non-linear mechanical behavior of fingertip, can lower the contact pressure significantly whilst maintaining sufficient rate of stability. Results thus support the thesis that correct shape and material determination of a tool-handle can increase the performance and comfort and thus lower the risk of acute and cumulative trauma disorders.
E.01 National awards
COBISS.SI-ID: 17845526