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

Abstract

Original scientific paper 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. Keywords: artificial neural network (ANN); bimetallic materials; DEFORM-3D; finite element method (FEM); load analysis; upper bound method (UB); upsetting Numerička analiza za predviđanje nastalog opterećenja i eksperimentalna provjera sabijanja bimetalnog diskaIzvorni znanstveni članak 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. Ključne

Determination of the Change in Electrical Conductivity of Single, Bimetallic and Trimetallic Cylindrical Billets with Plastic Deformation Induced by Upsetting Process

“…This value was converted to a resistance value, then this resistance value, thus the pressure value, was provided to the software as input value. Before the experiments, samples and flat molds were oiled, sanded and cleaned with alcohol using a special lubricant named MoS2 [8][9][10]. Fixing the system to the hydraulic press just before the test is shown in Fig.…”

“…Some models have small gaps between layers after 30% reduction. It has been observed that the interior materials especially the meridian cross section flow very rapidly and a barrel profile is different from a normal barrel spring [10][11][12]. Since the outer materials generally trap the inner cylindrical metal, especially the interfaces close to the die cannot move easily.…”

“…The hydraulic press is equipped with a pressure-current transducer to measure the upsetting load and save it to the computer. The load or pressure value can be read by an I/O card of the personal computer during the upsetting experiment.Before the experiments, samples and flat molds were oiled, sanded and cleaned with alcohol using a special lubricant named MoS2[8][9][10]. Fixing the system to the hydraulic press just before the test is shown in Fig.4.…”