Speaker:

Dr. Drazan Kozak（professor）

https://sfsb.unisb.hr/zavod-za-strojarske-konstrukcije/drazan-kozak-cv/

Title1:

Additive manufacturing (AM) / 3D printing in general

Abstract1:

What is 3D Printing? How is the technology being used? Application of the AM in a real practice.Most commonly used materials in AM. Seven basic AM techniques depending on layer deposition and materials used for the process. The influence of additive process parameters on the mechanical properties of printed components, component resolution and surface regularity. Process of attaining a complex model or assembly includes. CAD modelling of complex part or assembly, tessellation of CAD model (conversion to STL format), slicing STL model in layers using Slicer software, generation of printing paths (G-code), printing on a printing machine, post-processing of a model (if needed). The most important advantages and disadvantages of the AM. What are the challenges with 3D Printing?

Title 2:

Mechanical properties of printed porous materials

Abstract2:

What present porous structures and what is their engineering purpose? Types of porous structures according to the geometry. Lattice and gyroid structures – formulation and mechanical benefits. The influence of different shapes and different volume ratios of open-porous structures on the mechanical properties. Case studies:

(1) Study of sound absorption properties of 3D-printed open-porous ABS material structures

(2) Setup for natural frequency investigation of the FDM printed porous specimens

(3) Compression testing of the ABS porous material

(4) Tensile and bending test properties of the ABS lattice structure

(5) Eigen frequency measurement carried out on the metallic porous material (Inconel 718).

9:00-10:00

Speaker :

Dr. Petar Dimitrov

https://www.linkedin.com/in/dipetar/

Title 1:

Flight dynamics modeling and flight simulation- - Introduction and software used

Abstract 1:

The open source projects “FlightGear” and “JSBSim” along with “Datcom+pro” combined and used together provided a compact position for building a model and producing a simulation, i.e. modelling and flight model simulation, using low-cost or free software. Essential configuration files were constructed in “JSBSim” and combined at the end with “FlightGear” in order to model the Cranfield Jetstream J31 aircraft (a small twin-engine aircraft with a pressurised fuselage).

Title 2:

Flight dynamics modeling and flight simulation - Modeling and dynamics

Abstract 2:

The outcomes of the project introduced in lecture 1 were a “JSBSim” flight dynamics files importable in “FlightGear”, model developed with the use of “Datcom+pro” and a three-dimensional graphical model for the Cranfield Jetstream 31 aircraft.

10:00-11:00

Spearker:drRenata Troian

https://www.insa-rouen.fr/renata-troian

Title 1:

Bio-inspired design in structural mechanics

Abstract 1:

Introduce fundamental concepts of Bio-Inspired Mechanical Design, an approach that seeks solutions to human challenges within the natural world. Methods and solutions from structural mechanics will be studied.

Goal

∙ Look out of the box of traditional mechanics

∙ Overview of non-conventional mechanical approaches to structural mechanical design in nature

∙ Implementation of bio-inspired concepts

Focus

∙ Concentrate on physical part (structure, mechanisms) of organisms

Learning Objectives

After completion of this course students will be able to:

1. Describe methods for creative design

2. Identify mechanical working principles in biological structures:

3. Apply methods of structural design inspired by natural evolution.

Title 2:

Biological materials, structural principles

Abstract 2:

Methods and solutions from the mechanics of materials will be studied.

Goal

∙ Look out of the box of traditional materials

∙ Overview of non-conventional mechanical approaches for material design in nature

Learning Objectives

After completion of this course students will be able to:

1. Describe methods for creative design

2. Identify materials working principles in biological structures:

∙ Explain their design with a known mechanical theory

11:00-12:00

Speaker:

Dr. PEDRO Ribeiro

https://paginas.fe.up.pt/~pmleal/

Title1:

Non-linear dynamics of damagedthin-walled structures

Abstract1:

The mechanical properties of thin-walled structures can be significantly reduced bydamage, which can have diverse natures.Changes introduced in a structure result in changes in its dynamic behavior, leading to vibration structural health monitoring (VSHM) methods. Cracks, delamination and debonding are damages that have in common the fact that two surfaces disconnect. When these surfaces experience intermittent contact,the system is non-linear.This lecture addresses the analysis of the vibratory response of structures with the aforementioned types of damage. The followingmonitoring signalswill be employed: time-histories, phase-space trajectories, Poincare sections, and frequency spectra. Two case studies are analysed in detail. The first is abeam with a breathing crack, where the bilinear behaviour due to the crack closing and opening is considered. The equations of motion are obtained via ap-version finite element method, with shape functions proposed specifically for problems with abrupt localised variations. To analyse the dynamics of cracked beams, the equations of motion are solved in the time domain, via Newmark’s method, and the ensuing displacements, velocities and accelerations are examined. The second case study is astiffened composite laminated plate. Now, the analysis is carried out in Abaqus finite element software. The stiffened panel is part of a wing representative structure, investigated in the framework of COST action CA18203. Numerical and experimental analysis indicate that debonding between the composite plate and the stiffener is prone to occur. Therefore, damage of this type is here considered, at critical areas found in static analyses. The structure undergoes harmonic loading and contact restrictions between damaged surfaces are imposed. In both case studies, it is found that non-linear dynamics based tools can be employed to detect damage.

Title2:

Vibrations of variable stiffness composite laminated panels

Abstract2:

This lecture addresses vibrations of variable stiffness composite laminated (VSCL) plates and shells, where the reinforcement fibers are curvilinear. After an introduction to this type of composites, their constitutive relations are addressed. Unlike what occurs in straight fiber composites, these constitutive relations change in the panel’s domain. To account for moderately large displacements, which lead to geometrical non-linearity, von Kármán’s stress-strain relations are adopted. The ordinary differential equations of motion of VSCL panels are obtained by the principle of virtual work in conjunction with thep-version finite element, with hierarchic basis functions. Thin, first-order shear deformation and third-order shear deformation theories are overviewed. Considering first linear oscillations, the natural frequencies and mode shapes of different VSCL panels are computed and compared with the ones of constant stiffness laminates. Then, the non-linear modes of vibration are studied. Finally, the response to external forces is analyzed. It is verified that the curvilinear fibers can lead to significant differences both in the modes of vibration and in the response to external forces.

12:00-13:00

Spearker:

Prof. Valentina Golubovic-Bugarski

http://mf.unibl.org/nastavnici/valentina-golubovic-bugarski/

Title1:

Theoretical and experimental approach to structural testing

Abstract1：

A clear understanding of structural dynamics is essential to the design and development of new structures, and to solving noise and vibration problems on existing structures. This lecture gives a short introduction to modal analysis as a theoretical approach and to modal testing as an experimental approach in solving structural dynamics problems. Modal analysis is an efficient tool for describing, understanding, and modeling structural behavior. A distinction has been made between analytical and experimental approaches, with the focus on the experimental techniques. Emphasis has been placed on the broadband testing technique realized by use of dual-channel FFT analyzers. Modal analysis of the data obtained from modal testing of the structure results in modal model, which represents a definitive description of the structure’s response and can be evaluated against design specifications.

Title2:

Investigation of dynamic behaviour of one complex steel structure

Abstract2：

This paper deals with dynamic analysis of a steel structure, constructed by steel beams and pillars which are connected by bolts. This structure is designed to serve as an acoustic barrier to one rotating machine which generates an air borne and structure borne sound and vibrations on certain frequencies. This excitation energy is transmitted to the steel structure and might cause the oscillations of the structure. Depending on the frequency of the source of excitation, oscillations of the structure may occur at one of its natural frequencies, which depends on the physical characteristics of the structure - shape, dimensions, materials, grounding conditions, as well as other structural parameters. If it happens that excitation frequencies and the natural frequencies of the structure coincide to each other, a resonant oscillation of the structure will occur. To avoid the resonant oscillation of the structure, it is necessary the structure be designed such a way that its natural frequencies are not in the operating frequency range of the source of vibration. The investigated steel structure is subjected to mass and stiffness changes due to inserting some additional elements. The change of these physical characteristics of the structure can lead to change of its natural frequencies. To investigate dynamic behavior of overall structure, a numerical model was set by FEM analysis and experimental analysis was done using modal test and bump test.

13:00-13:30

Spearker:

PhD Trisovic Zaga

https://www.linkedin.com/in/zaga-trisovic-1a078a137/?originalSubdomain=rs

Title:

Water purifying from the wells of the lower water aquifers.

Abstract:

Purification of drinking water plays an important role in maintaining public health, because water is the most essential element to life and the main agent for basic hygiene. Given the importance, the parameters of the chemical and bacteriological quality of water are defined with the regulation from 1998 which identifies the maximum allowable concentrations of chemical substances and bacteria in drinking-water.

13:30-14:00

Speaker:

Prof. Trisovic Tomislav

https://www.itn.sanu.ac.rs/tomislavtrisovic_eng.html

Title:

Electrochemical disinfection of water by means of the in-situ of obtaining hypochlorite from dilute chloride solutions in a flowing electrochemical cell with spiral electrodes.

Abstract:

Disinfection is the basic and obligatory treatment of drinking water. There are several compounds that are used as disinfectants: chlorine gas, sodium hypochlorite, chlorine dioxide, dichlorocyanourate, hydrogen peroxide, potassium permanganate and others. The latest devices currently in use in the world are devices that produce disinfectants in situ at the point of need.

14:00-15:00

Speaker:

Prof. Natasa Trisovic

https://www.mas.bg.ac.rs/fakultet/nastavnici/211

Title1:

Wavelets-An overview of vibration-Related applications

Abstract1:

In this presentation an overview of wavelets vibration-related applications for evolutionary spectrum estimation, random field simulation, system identification, damage detection, and material characterization is given. Wavelet-based approaches are significant tools for joint time-frequency analysis of problems related to vibrations of mechanical and structural systems. This applies to the characterization of the system excitation, the system identification, and system response determination. Several examples exist in the nature of stochastic phenomena with a time-dependent frequency content.

Title2:

Uncertainty quantification and simulation in dynamic optimization procedures.

Abstract2:

Most numerical simulations of physical systems are rife with sources of uncertainty. Uncertainty in simulations stems from the stochastic nature of geometric and physical parameters, indeterminate nature of initial/boundary conditions, and inadequacy of physical models coupled with discretization errors. The presentation deals with the problem of improving dynamic characteristics of some structures. New dynamic modification procedure is given as the distribution of potential and kinetic energy in every finite element is used for analysis. In addition, the paper will discuss the introduction of a probabilistic treatment of important problem parameters.