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 - Jónás, Szabolcs AU - Tisza, Miklós AU - Kovács, Péter Zoltán TI - Investigation of aluminium clinched joints by FEA JF - IOP CONFERENCE SERIES: MATERIALS SCIENCE AND ENGINEERING J2 - IOP CONF SER MATER SCI ENG VL - 1246 PY - 2022 PG - 7 SN - 1757-8981 DO - 10.1088/1757-899X/1246/1/012003 UR - https://m2.mtmt.hu/api/publication/33069397 ID - 33069397 AB - The aim of the present paper is to compare the results of clinch joining simulations of two finite element software. The comparison is taken in between the resultant force-displacement curves, and in between the most important geometrical parameters of the joints, as the undercut (C) and neck thickness (t N ). The joining process was performed between two AA6082 sheets in two different heat treatment conditions by a TOX clinching tool. For the simulations the flow curves of material have determined by the so-called Watts-Ford compression test for both conditions. The applied FE software packages were the MSC.Marc&Mentat 2019 and the DEFORM2D 10.2. LA - English DB - MTMT ER - TY - JOUR AU - Béres, Gábor József AU - Tisza, Miklós TI - Analysis of the strength difference effect on tailor welded blanks’ springback JF - IOP CONFERENCE SERIES: MATERIALS SCIENCE AND ENGINEERING J2 - IOP CONF SER MATER SCI ENG VL - 1246 PY - 2022 SN - 1757-8981 DO - 10.1088/1757-899X/1246/1/012031 UR - https://m2.mtmt.hu/api/publication/33062219 ID - 33062219 AB - Tailor welded blanks (TWBs) are becoming widespread in the automotive industry due to their advantages, such as the possibility of weight reduction or the material usage optimising, resulting from the application. However, their main disadvantage is that the construction design and the simulation of the mechanical processes (like weld line movement, sheet springback, etc) are more complex. Predicting the mechanical response can only be done by accurately estimating the weld properties, which greatly increases the material testing requirements. Moreover, it often does not coincide with the matter of the field of material forming. In this study we focus on the simplified description of the springback of TWBs, to reveal which parameters have the primary influence on this process. Three kinds of DP steels with different strengths were welded to a mild steel grade one by one. Using these pairs we have varied both the strength difference between each sides and the average strength of the blanks, too. Uniaxial tensile tests were performed for the mechanical characterisation of each material, as well as right-angled bends perpendicular to the weld line were carried out to monitor the springback tendency of the samples. Our results show that a transition zone develops near to the weld line, independently from the strength difference between the TWB’s components. This zone is well-defined by linear functions, in which, the parameters are consistent with the physical content of the springback phenomenon. LA - English DB - MTMT ER - TY - JOUR AU - Béres, Gábor József AU - Lukács, Zsolt AU - Tisza, Miklós TI - Material parameters sensitivity on springback modelling of simple bending process JF - KEY ENGINEERING MATERIALS J2 - KEY ENG MATER VL - 926 PY - 2022 SP - 992 EP - 999 PG - 8 SN - 1013-9826 DO - 10.4028/p-41cjie UR - https://m2.mtmt.hu/api/publication/33060513 ID - 33060513 AB - Springback is one of the major defects that continuously concerns the sheet metal experts’ community. It is has long been known that the sheet thickness, the bending angle and the yield stress of the material primarily affect the angle change after the tools’ release. Besides, the consideration of the kinematic hardening ( KH ) model has powerful influence on the modelling results, too. In this study, we overviewed several possible factors on the springback with finite element modeling of a simple V-die bending operation, highlighting the effect of the material variables on the final shape. AutoForm® R7 software and the built-in theory of kinematic hardening were used for the material characterization, coupled with the Hockett-Sherby isotropic hardening rule as well as the Yld89 yield criterion. The material data for modeling kinematic hardening behavior were obtained by cyclic tension-compression tests, whilst the isotropic hardening and the yield surface parameters were acquired by simple uniaxial tension tests. The simulation results were compared to the experimental springback observations obtained by a CNC bending machine, without using springback compensation. A detailed parametric study was also carried out to highlight the level of criticality of the applied material variables on the final angle change. LA - English DB - MTMT ER - TY - CHAP AU - Jónás, Szabolcs AU - Tisza, Miklós AU - Kovács, Péter Zoltán ED - Szabó, Péter János ED - Kónya, Ildikó ED - Szakáts, Gergely TI - Alumínium lemezek klincs kötéseinek vizsgálata T2 - XIII. Országos Anyagtudományi Konferencia PB - [s.n.] CY - [s. l.] SN - 9786155270642 PY - 2021 SP - 49 UR - https://m2.mtmt.hu/api/publication/32541554 ID - 32541554 LA - Hungarian DB - MTMT ER - TY - CHAP AU - Jónás, Szabolcs AU - Tisza, Miklós AU - Kovács, Péter Zoltán TI - Klincs kötések vizsgálatának egyszerűsített modellezési lehetőségei T2 - VI. Gépészeti Szakmakultúra Konferencia PB - Gépipari Tudományos Egyesület (GTE) CY - Budapest SN - 9789639058446 PY - 2021 SP - 1 EP - 6 PG - 6 UR - https://m2.mtmt.hu/api/publication/32541540 ID - 32541540 LA - Hungarian DB - MTMT ER - TY - JOUR AU - Tisza, Miklós TI - Korszerű, nagy szilárdságú autóipari acélok fejlesztése JF - ACTA MATERIALIA TRANSYLVANICA (HU) J2 - ACTA MATER TRANSYLV (HU) VL - 4 PY - 2021 IS - 1 SP - 9 EP - 17 PG - 9 SN - 2601-1883 DO - 10.33923/amt-2021-01-02 UR - https://m2.mtmt.hu/api/publication/32195354 ID - 32195354 LA - Hungarian DB - MTMT ER - TY - JOUR AU - Jónás, Szabolcs AU - Tisza, Miklós TI - Klincselt kötések egyszerűsített modellezése JF - MULTIDISZCIPLINÁRIS TUDOMÁNYOK: A MISKOLCI EGYETEM KÖZLEMÉNYE J2 - MULTIDISZCIPLINÁRIS TUDOMÁNYOK VL - 11 PY - 2021 IS - 4 SP - 309 EP - 317 PG - 9 SN - 2062-9737 DO - 10.35925/j.multi.2021.4.35 UR - https://m2.mtmt.hu/api/publication/32095999 ID - 32095999 LA - Hungarian DB - MTMT ER - TY - JOUR AU - Meknassi, Raid AU - Kumar, Baibhaw AU - Tisza, Miklós TI - Comparison Study between TBF and Q&P Steels in Sheet Metal Forming: An Overview JF - INTERNATIONAL RESEARCH JOURNAL OF ENGINEERING AND TECHNOLOGY J2 - IRJET VL - 8 PY - 2021 IS - 3 SP - 3131 EP - 3134 PG - 4 SN - 2395-0072 UR - https://m2.mtmt.hu/api/publication/31945121 ID - 31945121 AB - The modern automobile industry reached a high level of development of steel grades with extraordinary strength and formability, through different new production processes and new processing strategies. The third generation of advanced high strength steel is a new concept that have been developed lately and have already been incorporated in the modern car body structures. The main objective of this work is to review some recent third-generation advanced high strength steel grades applied in sheet metal forming processes mainly from the viewpoint of automotive industry. LA - English DB - MTMT ER - TY - JOUR AU - Meknassi, Raid AU - Tisza, Miklós TI - Third generation of advanced high strength sheet steels for the automotive sector. A literature review TS - A literature review JF - MULTIDISZCIPLINÁRIS TUDOMÁNYOK: A MISKOLCI EGYETEM KÖZLEMÉNYE J2 - MULTIDISZCIPLINÁRIS TUDOMÁNYOK VL - 11 PY - 2021 IS - 4 SP - 241 EP - 247 PG - 7 SN - 2062-9737 DO - 10.35925/j.multi.2021.4.28 UR - https://m2.mtmt.hu/api/publication/31945076 ID - 31945076 AB - The modern vehicles demand a better fuel economy, decrease in ozone harming substance outflows, and superior safety requirements led to new developments of steel grades with higher strength and good formability. Third generation of advanced high strength steels are the next stage for the automotive companies in steel sheets development. The principal concept of third generation of AHSS is to reap the mechanical properties benefits from first and second generation of AHSS at cost neither too high nor too low. This literature review summarizes the results achieved in a previous paper of the Third Generation of Advanced High Strength Sheet steels literature published by D. Krizan et al. Where we intend to focus on, the recent developments and future trends of the third generation of advanced high strength sheet steels (3-GEN AHSSs) including quenching and partitioning (Q&P), TRIP bainitic ferrite (TBF), medium manganese, density reduced TRIP (δ-TRIP) and nano steels for the modern automotive industry, with emphasis on their main characteristics, processing, and applications LA - English DB - MTMT ER -