A Comparative Evaluation of Predictive Models of the Flat Rolling Process

The predictive abilities of several mathematical models of the cold, flat rolling process are tested by comparing their predictions to experimental measurements. The models include an empirical model, a one-dimensional model, a finite element model and an upper bound model. The coefficient of friction and the friction factor are first determined by the inverse approach, using the model deemed to be the most comprehensive. The effects of including or excluding an account of roll flattening, using elastic-plastic or rigid-plastic strips, and constant or velocity dependent coefficients of friction or friction factors are examined

17. Simpozij „Materijali i metalurgija“ – dopuna „Zbornik sažetaka”

In Metalurgija 63 (2024) 2,303-320 published „ Book of Abstracts “ (224). Deadline for received of Abstracts was November, 30,2023 y. Many authors have request new deadline by March, 25, 2024 y. Organizing committee have accept new deadline. Now it published supplements of 103 Abstracts.U Metalurgiji 63 (2024) 2,303-320 objavljen je Zbornik sažetaka (224). Rok za primitak sažetke je bio 30. studeni 2023. god. Mnogi autori zatražili novi rok do 25.03.2024. Organizacijski odbor Simpozija je prihvatio novi termin. Objavljuje se sada dodatnih još 160 sažetaka

A numerical study for prediction of forming load and experimental verification of bimetallic disc upsetting

U ovom je istraživanju postupkom sabijanja ispitivano nastajanje pločastih uzoraka sastavljenih od aluminija i bakra. Razvijen je pristup za predviđanje opterećenja koje dovodi do deformacije u postupku sabijanja. U radu se kombinira model metode konačnih elemenata, neuronske mreže i metode gornje granice (upper bound) u svrhu simuliranja i predviđanja opterećenja koje dovodi do deformacije u postupku sabijanja bimetalnih materijala. Rezultati metode konačnih elemenata (FEM) dobiveni su softverom DEFORM-3D te su uspoređeni i provjereni na eksperimentima uzimajući u obzir stvoreno opterećenje. Primijenio se i model Umjetne Neuronske Mreže (Artificial Neural Network - ANN) za analizu i predviđanje nastalog opterećenja kod različitih parametara postupka. Za procjenu nastalog opterećenja predložen je i Upper Bound (UB) model, a rezultati su eksperimentalno uspoređivani. Ustanovilo se da su dobiveni rezultati u skladu s eksperimentalnima u sabijanju bimetalnih šupljih diskova. Prema tome, predloženi ANN, FEM i UB modeli pružaju dragocjen uvid u parametre koji utječu na stvaranje opterećenja i može ih se smatrati korisnim alatima za predviđanje stvaranja opterećenja bez potrebe bilo kakvih eksperimenata.Forming of disc samples composed from aluminium and copper in performed study was examined with upsetting procedure. An approach for prediction deformation load of upsetting processes is developed. This study combines the finite element method model, neural network model and upper bound method to simulate and predict the deformation load in upsetting of bimetallic materials. The Finite Element Method (FEM) results were obtained from DEFORM-3D software and they were compared and validated with experiments by taking forming load into consideration. Also, Artificial Neural Network (ANN) model was used to analyze and predict the forming load for different process parameters. The Upper Bound (UB) model was also proposed to estimate the forming load and the results were compared with experiments. It was understood that calculated results were in concordance with experimental results in upsetting of bimetallic hollow discs. Thus, proposed ANN, FEM and UB models provide a valuable insight into the parameters affecting forming load and can be named as useful tools to predict the forming load without the need of any experiments

Ultrasound for Material Characterization and Processing

Ultrasonic waves are nowadays used for multiple purposes including both low-intensity/high frequency and high-intensity/low-frequency ultrasound. Low-intensity ultrasound transmits energy through the medium in order to obtain information about the medium or to convey information through the medium. It is successfully used in non-destructive inspection, ultrasonic dynamic analysis, ultrasonic rheology, ultrasonic spectroscopy of materials, process monitoring, applications in civil engineering, aerospace and geological materials and structures, and in the characterization of biological media. Nowadays, it is an essential tool for assessing metals, plastics, aerospace composites, wood, concrete, and cement. High-intensity ultrasound deliberately affects the propagation medium through the high local temperatures and pressures generated. It is used in industrial processes such as welding, cleaning, emulsification, atomization, etc.; chemical reactions and reactor induced by ultrasonic waves; synthesis of organic and inorganic materials; microstructural effects; heat generation; accelerated material characterization by ultrasonic fatigue testing; food processing; and environmental protection. This book collects eleven papers, one review, and ten research papers with the aim to present recent advances in ultrasonic wave propagation applied for the characterization or the processing of materials. Both fundamental science and applications of ultrasound in the field of material characterization and material processing have been gathered