COMPETENCES
The activities of the Department for Mechanical Design (DMD) include the complete analysis during development and design of the product: structure design by using CAD tools, calculation and analysis of structures by using analytic expressions and numeric methods (Finite element method) with structure optimisation and development of different methods for evaluation of single design solution, experimental analysis of finished products and models through planning of experiments. Scientific-research work of the Department and the cooperation with the economy are the basis for improving the education process.
The members of the Department are involved in solving numerous problems that occur in the process of design, production and exploitation in different production companies. The Department offers the following services:
- revision of calculations and projects,
- expertise of design and different fractures testing,
- redesign of products and development of products,
- structural integrity assessment,
- functional analysis of product,
- analytical and numerical computation of product,
- thermography,
- tensiometry,
- dynamical measuring,
- design and optimisation of new and existing products,
- eco-design,
- product life cycle monitoring,
- product modelling by CAD systems,
- implementation of evaluation methods for selection optimal design solution.
DMD consists of two chairs: Chair for Mechanics and Strength and Chair for Machine parts and Design. The Department has 12 staff members (2 full professors tenure, 2 associate professors, 2 assistant professors, 2 postdoctoral researchers and 4 assistants. DMD is currently involved in 4 national scientific research projects financed by Ministry of Science, Education and Sports of Republic of Croatia. Also DMD is involved in several bilateral international projects and projects related to cooperation with the economy.
Laboratories:
DMD has 6 laboratories that are used for education, scientific and research activities, as well as cooperation with the economy:
Laboratory for Mechanical Design
This laboratory is used for classic measuring: deformation, stress, force, displacement, velocity, acceleration, pressure, etc. The measuring can be static or variable. The testing can be done in the laboratory on real models, as well as on the work site on real objects: machines, vehicles, plants, steel structures, etc. Laboratory is also used in the education process.
Laboratory for Mechanical Testing
This laboratory is used for analysis of crack propagation. For this purpose stereomicroscope is used for measuring of parameters in fracture mechanics, for recording of crack propagation on the samples, the structure of sample surface, etc.
Laboratory for Engines and Motor Vehicles
This laboratory deals with testing of small engines, in order to monitor ecologically sensitive parameters. The testing can be done in laboratory conditions, as well as on the work site. Laboratory testing includes: characteristic Diesel engines in agricultural machinery. The testing of engines can be done in the working conditions with simultaneous monitoring of Diesel engines. Laboratory is also used in the education process.
Computer Classroom ĐĐ
This classroom (with 21 seats) is equipped with state of the art IT equipment (Lenovo computers) and it is used for educating students. It can be used for different programme systems: drawing, modelling, design, etc. Classroom is also used for training activities for companies from the field of 3D modelling.
Laboratory for Product Development (LECAD) Slavonski Brod
LECAD Slavonski Brod is the member of the LECAD Group which consists of: LECAD Ljubljana, LECAD Zenica, LECAD Novi Sad and LECAD Belgrade. Aims and action of LECAD Slavonski Brod: development of design theory and design process, product and systems development, education and life cycle education, product and systems design, publishing, development of PDM/PLM systems, industrial design, eco-design, education in a international environment with possibility to use modern laboratories out of Croatia, etc. Chair for LECAD Slavonski Brod: Professor Milan Kljajin (Milan.Kljajin@unisb.hr).
APPLICATIONS
DMD is currently involved in 4 national scientific research projects, funded by the Ministry of Science, Education and Sports of the Republic of Croatia:
Project title: Analysis and Fracture Assessment of Structures of Anisotropic Materials
Project coordinator: Professor Dražan Kozak (Drazan.Kozak@unisb.hr)
Project title: Products Properties for a Global Product Realization by Rapid Production
Project coordinator: Professor Milan Kljajin (Milan.Kljajin@unisb.hr)
Project title: Numerical Modelling of Convection-Diffusion Phase Change Problems
Project coordinator: Professor Marija Živić (Marija.Zivic@unisb.hr)
Project title: Research of the IC Engine Combustion Control and management
Project coordinator: Professor Marinko Stojkov (Marinko.Stojkov@unisb.hr)
RESULTS OBTAINED
The results of the project Analysis and Fracture Assessment of Structures of Anisotropic Materials in years 2010/2011:
Investigation related to structural integrity assessment of heterogeneous structures was successfully completed. Previously known investigations included only structural assessment of homogeneous structures or structures with one level of material mismatch, and existing structural integrity assessment methods where limited in their applications to such structures, making it impossible to assess heterogeneous structures with two levels of material mismatch. A compendium of yield load solutions is generated for I butt welded repaired welded joint in context of three point bend specimen. Such work included systematic investigation of influence of geometry parameters and mechanical properties of present materials in weld, primarily using finite element method and statistical methods to derive mathematical expressions needed for compendia generations. Failure criterion for yield load solutions was load value causing yield zone to spread across the whole net-section of investigated specimen. This compendium was implemented in SINTAP procedure (Structural INTegrity Assessment Procedure), with some adaptations in order to generate a module for assessment of heterogeneous structures.
Furthermore, this extensive investigation gives insight in complex interaction between geometrical parameters and mechanical properties of weld materials with fracture resistance of heterogeneous welded joints.
As a result of this investigation, a PhD thesis ″Analysis of weld geometry and mechanical properties of weld materials on fracture behaviour of repaired welded joints″ was successfully finished by Pejo Konjatić, a young researcher on this project.
Therefore, it is the project with most publications in the scientific area of mechanical engineering with 43 publications in journals and 38 publications at international conference.
The results of the project Products Properties for a Global Product Realization by Rapid Production in years 2010/2011:
Input lists generation model for new products was finished and tested. The input lists generation model is a general model, faced with all necessary know-how to ensure the development of MFF (Matrix of Function and Functionality). The input list is a list where all input data that are to be used for calculations and bindings between functions and functionalities are defined and specified. Since in this case we are dealing with bindings between functions and functionalities within MFF, two input lists should be defined-the functions list and the functionalities list.
Input list of functions reflect market needs, representing simultaneously input functional requirements, ideas and engineering goals. These requirements are the first information on a possible new product.
In accordance with the MFF model, all defined functional requirements are specified by means of Names Suggestor, which takes care of credibility and correctness of a new entry. Input lists of functionality describe functions holders of a particular functionality. They materialize through the execution by means of particular processing, manufacturing, working, assembly, transport and application technologies. The functionality list can be specified according to a personal opinion or decisions or the relevant choice is left to the automated suggestion by the software package for the generation of input lists. Following the algorithm, it examines matches with existing solutions in the database and suggests a solution-functionality-on the basis of percentage match. Well-described data in the database are the basis for quality definitions of functionalities. During the description and descriptions generation, the Names Suggestor takes care of it.
The results of the project Numerical Modelling of Convection-Diffusion Phase Change Problems in years 2010/2011:
Generation of the algorithm for the calculation of velocity field, pressure and temperature field involves development of the mathematical model, development and implementation of the appropriate method for the simultaneous solving of the equations in the liquid and solid phase with prescribing the condition on the time dependent phase boundary. In the first phase of the project, the mathematical model for the simulation of a phase change process of the pure substances based on the enthalpy method is developed and a comparison of this model with the previously developed mathematical model, in which latent heat is considered through the source term of the energy equation, is performed.
In the second phase, the numerical model is created and the new algorithm based on the enthalpy method and computer program are developed for the computation of phase change problem. The research area also was based on the development of the mathematical model and computer program for the simulation of heat and mass transfer process in the binary mixture. The testing of the program is done and the comparison of the time dependent velocity and temperature field with results computed with commercial software and analysis of the natural convection driven by the temperature and concentration differences in the binary mixture are performed.
The results of the project Research of the IC Engine Combustion Control and management in years 2010/2011:
Investigation was focused on the thermodynamic process inside the cylinder of internal combusting engine. It is necessary to optimize the IC engine combustion process to ensure optimal parameters during the conversion of heat energy into mechanical work inside the engine. Using simulations, the possibility of controlling the optimization process by using the required amount of fuel in the process of injecting the fuel into the cylinder was investigated. Three models were tested: prof. Woschni Model, Lotus Model and prof. Medica Model.
The Woschni Model, based on the classical Wiebe function (which is used to predict the burn function and burn rate in internal combusting engines), shows relatively few variable parameters and requires complex computer support. Therefore, it is extremely complicating to improve this model.
The Lotus Model is commercial model with excellent characteristics and possibilities, but a special license is needed for its use. The price is extremely high and therefore not within our modest budget.
The Medica Model (also researched in this project) can encompass all the needs of the project concerning the applied research and optimization of combusting process. It requires special training, as well as very demanding computer memory. This will be the basis for research in the next period.
INDUSTRIAL SECTORS OF APPLICATION
- Design and product development
- Optimisation
- Heavy industry
- Processing industry
- Light industry
ACCOMPLISHED INDUSTRIAL APPLICATIONS
Project title: Numerical analysis of structures
Project coordinator: Professor Dražan Kozak
Project ordered/funded by: ĐĐ Termoenergetska postrojenja d.o.o. Slavonski Brod
Short description: Technical report includes results of numerical investigation of elastic-plastic behaviour of pipelines between overheater-overheater chamber, using finite element method.
Collaborator on project: assistant Josip Sertić.
Project title: Measuring of vibrations on a tank
Project coordinator: Professor Todor Ergić
Project ordered/funded by: ĐĐ Specijalna vozila d.d. Slavonski Brod
Short description: Measuring of vibrations on a tank was done in order to determine their intensity. These results were used to reduce the intensity of vibrations.
Project title: Determining the factors that caused the accident of crane DEMAG HC 240
Project coordinator: Professor Franjo Matejiček
Project ordered/funded by: Općinski sud u Slavonskom Brodu
Short description: Mechanical-hydraulic elements were tested and analysed in order to determine the cause of the crane accident.
Project title: Technical and technological documentation for the adaptation of sunflower harvest
Project coordinators: Professor Dražan Kozak and Professor Željko Ivandić
Project ordered/funded by: Same Deutz-Fahr Žetelice d.o.o. Županja
Short description: Technical and technological documentation for AS 5,4m; 6,3m and 7,2m for the adaptation of sunflower harvest. Documentation was made in Unigraphics NX 3.0.
Collaborators on project: dr.sc. Pejo Konjatić and dr.sc. Mirko Karakašić.
Project title: Determining the capacity of the glass panel carrier by the Finite element method
Project coordinators: Professor Dražan Kozak and Professor Željko Ivandić
Project ordered/funded by: TUV Croatia d.o.o Slavonski Brod
Short description: According to the technical documentation, technical report is made. The report contains analysis of stresses, strains and safety factors.
Collaborators on project: dr.sc. Pejo Konjatić and dr.sc. Mirko Karakašić.
Project title: Determination of capacity of two-layer oil tank 60 m3
Project coordinators: Professor Dražan Kozak and Professor Ivan Samardžić
Short description: Project task includes preparation of technical report, which includes assessment of capacity for crude oil tank of 60 m3 volume. According to the technical documentation, oil tank has two chambers (30 + 30 m3). One chamber is loaded with testing pressure of 2 bar.
Project title:Report of the measurement of forces in the clewlines on the tower St. Juraj, Biokovo Mountain
Project coordinator: Professor Todor Ergić
Project ordered/funded by: ĐĐ Inžinjering d.d.
Short description: These measurements where performed for the reconstruction of TV tower, whose capacity is needed to increase. Details of this project are available on: http://bib.irb.hr/prikazi-rad?&rad=560189.
Collaborators on project: assistant Darko Damjanović and assistant Tomislav Baškarić
Project title: Determination of cracks initiation causes at the tanks of UACNS wagons
Project coordinator: Professor Franjo Matejiček
Project ordered/funded by: ĐĐ Specijalna vozila d.d. Slavonski Brod
Short description: details of this project are available on: http://bib.irb.hr/prikazi-rad?&rad=348622. Collaborators on project: dr.sc. Pejo Konjatić and dr.sc. Mirko Karakašić.
Project title: Static calculation of strength and stiffness of boiler membrane wall – Boiler Bamberg
Project coordinator: Professor Dražan Kozak
Project ordered/funded by: ĐĐ Termoenergetska postrojenja d.o.o. Slavonski Brod
Short description: On set of incineration plant boilers, cracks on membrane walls were appeared. In this report the calculations of strength and stiffness of sideward membrane wall in zone of critical supports were presented. Done calculation determined a mistake in support design.
Collaborators on project: assistant Josip Sertić and assistant Mato Kokanović.
Project title: Numerical investigation of elastic-plastic behavior of pipelines between heat chamber and steam overheater
Project coordinator: Professor Dražan Kozak
Project ordered/funded by: ĐĐ Termoenergetska postrojenja d.o.o. Slavonski Brod
Short description: details of this project are available on: http://bib.irb.hr/prikazi-rad?&rad=384377. Collaborator on project: assistant Josip Sertić
Project title: Analysis of weld defect caused by lack of penetration in circumferential weld on the joint between pipe and elbow
Project coordinator: Professor Dražan Kozak
Project ordered/funded by: ĐĐ Termoenergetska postrojenja d.o.o. Slavonski Brod
Short description: Technical report contains research results of weld defect influence, type lack of fusion and lack of penetration, on strength of but weld joint of pipe. Analysis took in to consideration a static and dynamic influence of load. The problem of creep at increased temperature was considered.
Collaborator on project: assistant Josip Sertić, assistant Darko Damjanović and assistant Mato Kokanović.
Project title: Static calculation – Boiler Bolzano
Project coordinator: Professor Dražan Kozak
Project ordered/funded by: Planum d.o.o. Slavonski Brod
Short description: Technical report contains calculation of reactions in boiler supports and also the calculation of strength and stiffness of membrane walls and buckstays system. Existing calculation methods were improved and new procedures were developed. Besides analytic methods for determination of stress state, the finite elements method was also used on boiler.
Collaborator on project: assistant Josip Sertić, assistant Darko Damjanović and assistant Mato Kokanović.
POTENTIAL INDUSTRIAL APPLICATIONS
Potential industrial application is possible to see from the competences of the Department for Mechanical Design (DMD).
TRAINING ACTIVITIES FOR COMPANIES
- Training course from modelling by means of commercial CAD systems
- Training course from the numerical methods, prior Finite Element Method
- Design and optimisation of new and existing products
- Dynamical measuring
- Expertise of design and different fractures testing
- Structural integrity assessment
AVAILABLE INSTRUMENTATION
- 3 Workstations HP Z600
- 1 Workstation HP XW8200
- 1 Mobile Workstation HP Elite Workbook
- Measuring amplifier HBM-MGC plus (displacement receiver, acceleration reciever, software for data processing)
- The device for vibration measuring and balancing Roto Balance
- Ultrasonic device for measuring thickness DM 5E DL
- Laser vibration measuring device VibroMetTM 500V
- Microscope for monitoring propagation of cracks LEICA MZ 12-5
- Thermo graphic camera VarioCAMHiRes research 640
- Kimo Kiray 300 Infrared Thermometer
- FMX-003 Electrostatic Fieldmeter
- Kimo SL200 Solarimeter
- Hydraulic pump for testing pressure vessels
- NX software
- Solid Edge software
- Teamcenter software
- Tecnomatix software
- FEMAP software
- 3DS Max software
- Ansys software
- Computer classroom equipped with 21 computer and plotter HP Designjet 510
- Hydraulic Testing Machine Carl Schenck AG-Darmstadt, machine for static and dynamic analyzing, 1000 kN, possible tensile and pressure loads
RESEARCH GROUP
Department for Mechanical Design
Mechanical Engineering Faculty in Slavonski Brod
Trg I. Brlić-Mažuranić 2
HR-35000 Slavonski Brod
Contact person: Associate Professor, Pejo Konjatić, Head of Department (Pejo.Konjatic@unisb.hr)
Chair for Mechanics and Strength
Contact person: Assistant Professor, Marko Katinić, Head of Chair (Marko.Katinic@unisb.hr)
Chair for Machine parts and Design
Contact person: Associate Professor, Mirko Karakašić, Head of Chair (Mirko.Karakasic@unisb.hr)