The aim of this paper is to study the quasi-static and dynamic compressive crush performance of newly developed in-situ foam-filled tubes (FFTs) made of light aluminium alloys prepared by powder compact foaming technique. By this method, the aluminium alloy empty tube is filled with an aluminium alloy foam during its formation. The axial mechanical crushing behaviour and the failure mechanisms were assessed by uniaxial compression tests coupled with infrared thermography. Results confirm that the in-situ FFTs have a more stable axial crush performance. The results also demonstrate that heat treated aluminium alloy structures ensure high ductility and very good crashworthiness since they deform without formation of cracks during compression, which is a pre-requisite for good and reliable crashworthiness behaviour.
COBISS.SI-ID: 18369814
The manuscript discusses mechanical properties and microstructure of copper before and after the explosive treatment. For this purpose testing of tensile copper specimens before and after explosive treatment has been performed. The experimental measurements have been supported by the 3D optical deformation measurement system (ARAMIS) and infrared thermography. The study shows that the explosive treatment significantly influences the global response of copper throughout the complete loading range. The uniform distribution of principle strain in untreated specimens is replaced by strain localization which appears just after the start of the loading resulting in much lower failure strain.
COBISS.SI-ID: 18561558
The paper reports findings of investigating optimal interface material parameters of product handle to improve its ergonomics by increasing the user performance, comfort, and lower the risk of cumulative trauma disorder development. Optimisation methods in combination with the finite element computer simulations of a human fingertip whilst grasping a handle were used to determine an interface foam material with optimal material properties for best mechanical behaviour of the system. A single objective function was defined to determine best material parameters of the interface foam material, which has to remain firm during low grasping forces to provide stability of the product grasp and appropriately deforms when a critical contact pressure is reached to provide higher contact area. This increases comfort and lowers the contact pressure on the hand and thereby the risk of injury development. The optimisation process yielded the optimised foam thickness and its stress-strain relationship for simulated contact of fingertip model grasping a product handle.
COBISS.SI-ID: 18906646
This paper aims to evaluate the potential use of closed-cell aluminium alloy integral-skin foams as stiffening elements for aluminium alloy thin-walled structures that are main basic components in the concept and design of automotive body parts. Foam specimens were prepared using the powder metallurgical route, inserted into empty thin-walled tubes and subjected to quasi-static and dynamic bending loading conditions. The effect of introducing foam into tubes was evaluated using the infrared thermography during the three-point bending tests. The foam-filled tubes, empty tubes and foams are compared in terms of the maximum load carrying capacity, crash energy absorption, specific energy absorption and deformation modes. Results showed that the foam filling leads due to interaction between the tube wall and foam filler, causing an increased bending response of the filled tubes which exceeds the sum of the bending response for the individual components. Their deformation mode is a combination between the modes of the individual components.
COBISS.SI-ID: 17349398
E-materials and various e-learning systems have become regular features in lower secondary schools in Slovenia and around the world. Many different systems and materials have been created for students, but only a few offer the same amount of individualisation that is present in traditional one to one teaching (one teacher to one student). The paper demonstrates the design and evaluation of an adaptive, intelligent and individualised intelligent tutoring system (ITS) based on the cognitive characteristics of the individual learner. The TECH8 model presented is designed modularly, based on a system for collecting a range of metadata and variables that are vital for the teaching process. Prepared in such a way, the proposed system supports individualization and differentiation; because of this, it can be adapted to each individual's level of knowledge and understanding of the subject matter. The TECH8 system was evaluated in a real learning environment. The results indicate that appropriately created TECH8 e-learning material yields results that are better than those from traditional teaching but not better than one to one teaching.
COBISS.SI-ID: 21042696