TY - CHAP AU - Lukács, Zsolt ED - Koncsik, Zsuzsanna ED - Lukács, János TI - Visszarugózásra kompenzált lemezalakító szerszámok tervezési gyakorlata AutoForm programrendszer alkalmazásával T2 - Kutatási eredmények a Miskolci Egyetem Gépészmérnöki és Informatikai Karának Anyagszerkezettani és Anyagtechnológiai Intézetében PB - Miskolci Egyetem, Gépészmérnöki és Informatikai Kar, Anyagszerkezettani és Anyagtechnológiai Intézet CY - Miskolc SN - 9789633583074 PY - 2023 SP - 29 EP - 36 PG - 8 UR - https://m2.mtmt.hu/api/publication/34444853 ID - 34444853 LA - Hungarian DB - MTMT ER - TY - CHAP AU - Lukács, Zsolt AU - Gál, Gaszton György AU - Dessie, Jemal Ebrahim ED - Koncsik, Zsuzsanna ED - Lukács, János TI - AA6082 nagyszilárdságú alumíniumlemez visszarugózási anyagparaméterei változásának fizikai és numerikus vizsgálata T2 - Kutatási eredmények a Miskolci Egyetem Gépészmérnöki és Informatikai Karának Anyagszerkezettani és Anyagtechnológiai Intézetében PB - Miskolci Egyetem, Gépészmérnöki és Informatikai Kar, Anyagszerkezettani és Anyagtechnológiai Intézet CY - Miskolc SN - 9789633583074 PY - 2023 SP - 19 EP - 28 PG - 10 UR - https://m2.mtmt.hu/api/publication/34444850 ID - 34444850 LA - Hungarian DB - MTMT ER - TY - JOUR AU - Béres, Gábor József AU - Weltsch, Zoltán AU - Borbély, Richárd AU - Kölüs, Martin László AU - Lukács, Zsolt AU - Tisza, Miklós TI - An extended stress-based forming limit diagram focusing on the wrinkling phenomenon and the effect of the normal pressure on clamped surfaces JF - JOURNAL OF MATERIALS PROCESSING TECHNOLOGY J2 - J MATER PROCESS TECH VL - 322 PY - 2023 PG - 20 SN - 0924-0136 DO - 10.1016/j.jmatprotec.2023.118196 UR - https://m2.mtmt.hu/api/publication/34225918 ID - 34225918 AB - A novel wrinkling limit representation following the pattern of the conventional forming limit curves (FLCs) and the stress-based forming limit curves (SFLCs) as well as the application of the assumed criterion in finite element modelling are discussed in this manuscript. FLCs can partially refer to the wrinkling potential in the area left to the uniaxial tension line, but just like the SFLCs, cannot characterize the limits of the material behavior in a deeper sense, if negative in-plane stress and normal pressure act together on the sheet. This study predicts the wrinkling risk of clamped surfaces with a stress-based criterion through solving the analytical equations of the critical compressive stress causing wrinkling, and the corresponding blank holder pressure. The critical values were calculated based on the Wang and Cao’s theory using Hill48 anisotropic yield function coupled with the Swift hardening law. The results draw a novel wrinkling limit curve representation methodology, in which the minor stress responsible for wrinkling and its ratio to the major stress are distinguished in the function of the applied blank holder pressure. The applicability of the calculated curves was investigated using finite element simulations, which showed that this method provides the opportunity to quantitatively interpret how close a component is to the wrinkling limit. The calculated wrinkling tendencies were verified by standard cup drawing tests supplemented by round shape error measurements on three different automotive steel sheets. It can be stated that the obtained numerical conditions of wrinkling were fitted to the experiments fairly well. LA - English DB - MTMT ER - TY - JOUR AU - Dessie, Jemal Ebrahim AU - Lukács, Zsolt TI - Experimental investigation of the effect of W-temper forming process parameters on springback JF - IOP CONFERENCE SERIES: MATERIALS SCIENCE AND ENGINEERING J2 - IOP CONF SER MATER SCI ENG VL - 1284 PY - 2023 PG - 10 SN - 1757-8981 DO - 10.1088/1757-899X/1284/1/012066 UR - https://m2.mtmt.hu/api/publication/34084534 ID - 34084534 AB - High strength aluminium alloys have drawn a lot of attention because of the expanding demand for lightweight vehicle design in the automotive sector. Due to poor formability at room temperature warm and hot forming have been advised. However, warm and hot forming methods need more steps in the production process and an advanced tooling system. In contrast, since ordinary tools can be used, forming sheets at room temperature in the W-temper condition is advantageous. However, a significant problem that must be resolved during the use of this technique is the springback of supersaturated sheets and their thinning. In this study, the high strength aluminium alloy was solution heat treated, and a U-shaped bending test was carried out at different time periods between W-temper heat treatment and forming operation. As a result, it is noted that the springback is highly dependent on the time between W-temper heat treatment and forming operations, and the change in shape increases with increasing time. The change in shape after forming was also evaluated using numerical simulation aiming to validate the experimental result. To determine the material parameters of the kinematic hardening model for numerical simulation, uniaxial tension-unload tests were performed under different ageing conditions. LA - English DB - MTMT ER - TY - JOUR AU - de Carvalho, Lucas Alexandre AU - Lukács, Zsolt TI - Experimental investigation of the effect of lubricant change on automotive component JF - IOP CONFERENCE SERIES: MATERIALS SCIENCE AND ENGINEERING J2 - IOP CONF SER MATER SCI ENG VL - 1284 PY - 2023 PG - 9 SN - 1757-8981 DO - 10.1088/1757-899X/1284/1/012088 UR - https://m2.mtmt.hu/api/publication/34084521 ID - 34084521 AB - Manufacturing problems resulting from lubricant supplier changes are relatively common in automotive press shops. Simulations using computer-aided design (process and tool) detect a significant proportion of manufacturing problems before tools are physically produced. In modern forming codes, an enhanced Coulomb model is used to numerically model the friction phenomena associated with lubrication. In the laboratory condition, determining model parameters through physical measurement is challenging. As a result, it became necessary to design a device that could be utilized in industrial environments. In this study, we present the prediction of a manufacturing problem resulting from a change in the lubricant of an industrial sheet metal part. The measuring device has been developed based on the parameters of the friction model of the lubricant materials. The developed measuring device may be used to determine the pressure and velocity dependent friction model parameters. The measuring device can only measure a limited range of pressures and velocities, so the results are extended to a wider range using a mathematical method. The results are used to demonstrate the effect of lubricant material changes on the forming process using the AutoForm code. LA - English DB - MTMT ER - TY - JOUR AU - Meknassi, Raid AU - Béres, Gábor József AU - Lukács, Zsolt TI - Prediction of strain distribution during the plane strain tensile test based on artificial neural networks JF - DESIGN OF MACHINES AND STRUCTURES J2 - DESIGN MACHINES STRUCTURES VL - 13 PY - 2023 IS - 1 SP - 74 EP - 83 PG - 10 SN - 1785-6892 DO - 10.32972/dms.2023.006 UR - https://m2.mtmt.hu/api/publication/34032485 ID - 34032485 AB - In this study, finite element method was used to study the effects of various notch geometries on the strain field distributions during the plane strain tensile test for cold-rolled steel (DC01). The artificial neural network approach (ANN) and the response surface methodology (RSM) were adopted to develop the mathematical prediction models applied in the optimization procedure. The strain state was expressed by self-defined metrics, namely, the Plane Strain State Index (PSSI) and the Homogeneity Index (HI) were predicted by changing the notch angle (X degree), notch width (d mm), and notch length (c mm). The Quadratic mathematical models obtained by the RSM, and ANN presented the evolution of PSSI, and HI based on (X, d, and c). The results show that the ANN method provides more precise results compared to those of the RSM approach. LA - English DB - MTMT ER - TY - JOUR AU - Dessie, Jemal Ebrahim AU - Lukács, Zsolt TI - Determination of Influential Springback Parameters in U-Bending Test JF - POLLACK PERIODICA: AN INTERNATIONAL JOURNAL FOR ENGINEERING AND INFORMATION SCIENCES J2 - POLLACK PERIODICA VL - 18 PY - 2023 IS - 2 SP - 17 EP - 22 PG - 6 SN - 1788-1994 DO - 10.1556/606.2023.00799 UR - https://m2.mtmt.hu/api/publication/33926283 ID - 33926283 AB - U-bending tests are the most common method to predict springback and are influenced by the process and geometrical variables in addition to material behaviour. It needs a numerical study at a high level with many variables to reduce try-out time and loop. In this study, the U-bending test of DC01 steel has been researched numerically and experimentally to govern the influential parameters. The numerical analysis was conducted using AutoForm-Sigma code. The die radius has an excessive influence on the change of flange angle tha the punch radius, but the punch radius has the greatest influence on the variation of the sidewall angle. The coefficient of friction played a great impact on both flange and sidewall angle deviation and its influence grows stronger as the blank holding force increases. LA - English DB - MTMT ER - TY - JOUR AU - Gál, Viktor AU - Lukács, Zsolt AU - Kovács, Péter Zoltán TI - Nagyszilárdságú acéllemezek törési határ alakváltozásának vizsgálati módszerei JF - ANYAGVIZSGÁLÓK LAPJA J2 - ANYAGVIZSGÁLÓK LAPJA VL - 2022 PY - 2022 IS - 2 SP - 41 EP - 47 PG - 7 SN - 1215-8410 UR - https://m2.mtmt.hu/api/publication/33695832 ID - 33695832 LA - Hungarian DB - MTMT ER - TY - CHAP AU - Meknassi, Raid AU - Béres, Gábor József AU - Lukács, Zsolt ED - Ahmat, Kazankaya ED - Mevlüde, Alev Ates TI - A COMPARATIVE STUDY ON PERFORMANCE OF NOTCHED TENSILE TEST SPECIMEN UNDER PLANE STRAIN CONDITION T2 - 2. Ahi Evran International Conference on Scientific Research PB - Kırşehir Ahi Evran University CY - Kırşehir SN - 9786258246643 PY - 2022 SP - 675 EP - 681 PG - 7 UR - https://m2.mtmt.hu/api/publication/33678728 ID - 33678728 LA - English DB - MTMT ER - TY - CHAP AU - Dessie, Jemal Ebrahim AU - Lukács, Zsolt ED - Homolya, Márton ED - Mankovits, Tamás TI - A NUMERICAL STUDY ON SPRINGBACK PREDICTION WITH SYSTEMATIC PROCESS IMPROVEMENT T2 - 8th International Scientific Conference on Advances in Mechanical Engineering (ISCAME 2022) PB - Department of Mechanical Engineering, Faculty of Engineering, University of Debrecen CY - Debrecen SN - 9789634904489 PY - 2022 SP - 31 EP - 32 PG - 2 UR - https://m2.mtmt.hu/api/publication/33575291 ID - 33575291 LA - English DB - MTMT ER -