The research presents experimental and numerical identification of the effect of dynamic effects on the sheet-metal blanking process. A novel laboratory blanking apparatus has been presented, offering a wide range of experiments with great repeatibility and controlled variation of process parameters. From the blanking experiment, yield and ultimate stresses in the out-of-plane direction are identified, and from the partial and sequential experiments, material damage, modelled by the Lemaitre damage model. Effect of material anisotropy in the in-plane direction on the out-of-plane characteristics is assesed. A numerical code, based on the extended finite element method and explicit central difference method, for two-dimensional modelling of elasto-plastic contact problems is presented, using damage accumulation up to fracture and crack propagation through the critically damaged area.
D.09 Tutoring for postgraduate students
COBISS.SI-ID: 14039579This study theoretically and experimentally compares a group of spectral moment methods, used to estimate the probability density of cycle amplitudes of the random uniaxial stress. Methods are compared on spectra, typical in the field of structural dynamics. A group of multiaxial criteria, used to reduce the multiaxial stress state to a uniaxial one, is also compared experimentally. Sample failure is achieved by taking advantage of its resonant response to broadband vibrations. An approach to vibration fatigue analysis using modal decomposition is presented.
D.09 Tutoring for postgraduate students
COBISS.SI-ID: 14956827This is a Proceedings of an International Conference on Engineering Vibration, held from 7.-10.9.2015 in Ljubljana. Over 200 delegates attended the conference form 30 countries worldwide.
B.02 Presiding over the programming board of a conference
COBISS.SI-ID: 14168859Vibration testing of components in automotive industry requires long testing times. To accelerate the vibration testing times without the loss of reliability of testing, a damage-based approach with the consideration of parameters defining vibration testing techniques is adopted. With special attention to excitation types sweep-sine and random, the damage based approach is applied. The vibration fatigue damage is researched from frequency domain point of view, considering the relationship between the time and the frequency domains. The Palmgren-Miner cumulative rule is applied to calculate the fatigue life. The application of the method is shown on two case studies. The results show that theoretical predictions can be used to compare different testing techniques, but are not so accurate when predicting actual times to failure.
D.09 Tutoring for postgraduate students
COBISS.SI-ID: 14221339Dynamic analysis of an alternator rectifier was conducted, both on numerical as well as at experimental level, aimed at increasing the fatigue life of the rectifier. Valid numerical model of rectifier was created, validated with experimental comparison. Design changes were proposed that lead to increased fatigue life. This was confirmed at electromagnetic shaker.
F.07 Improvements to an existing product
COBISS.SI-ID: 15526171