The Experts below are selected from a list of 37533 Experts worldwide ranked by ideXlab platform
Marion Merklein - One of the best experts on this subject based on the ideXlab platform.
-
influence of specimen size and Sheet Thickness on the material behavior of az31b under uniaxial tension
2016Co-Authors: Sebastian Suttner, Marion MerkleinAbstract:Concerning a low specific density, magnesium alloys offer a great potential to reduce the part weight. Due to the conditional formability of magnesium alloys at room temperature, forming processes are mostly realized at elevated temperatures. Within this contribution, uniaxial tensile tests for two different specimen geometries with a gauge length of 50 mm and 2 mm and a cross section of 12.5×1 mm2 and 2×1 mm2 are carried out for the magnesium alloy AZ31B at an elevated temperature of 200 °C. Since the specimen size is reduced, the influence of the Sheet Thickness needs to be analyzed. The analysis of the Sheet Thickness results in a change of the determined flow curve above a strain level of 0.1 and a much earlier failure of specimen with an initial Sheet Thickness of 1.5 mm. The changed material behavior can be explained by a different microstructure, e.g. the influence of the grain size. In summary, a characterization of the magnesium alloy AZ31B at elevated temperatures can be realized with a miniaturized test setup.
-
flexible rolling of process adapted semi finished parts and its application in a Sheet bulk metal forming process
2015Co-Authors: Philipp Hildenbrand, Thomas Schneider, Marion MerkleinAbstract:By applying bulk forming processes on Sheet metals, thin-walled functional components with locally restricted wall Thickness variations can be manufactured by forming operations. Using tailored blanks with a modified Sheet Thickness gradient instead of conventional blanks, an efficient controlling of the material flow can be achieved. One possible process to manufacture these semi-finished parts is a flexible rolling process. Based on an established process strategy new results for steels of differing strength and work-hardening behavior are presented in this paper. The influences of each material on the resulting process forces and blank properties regarding the same target geometry are discussed. The tailored blanks are hereby analyzed by their geometrical dimensions, like Sheet Thickness, and their mechanical properties, e.g. hardness distribution. Additionally, the possibilities of processing these tailored blanks in a deep-drawing and upsetting process are presented with a hereby focus on the residual formability of the tailored blanks.
-
fundamental investigations on the material flow at combined Sheet and bulk metal forming processes
2011Co-Authors: Marion Merklein, J Koch, Simon OpelAbstract:Abstract The class of combined Sheet and bulk metal forming (SBMF) processes denotes the forming of Sheet metals with typical bulk forming operations. As a consequence, simultaneous 2D and 3D stress and strain states are present. Furthermore the local shape elements formed out of the Sheet plane are in the magnitude of the Sheet Thickness. This paper deals with process combinations upsetting/lateral extrusion and deep drawing/upsetting. It has been shown that an insufficient mould filling is nearly inevitable using conventional tooling systems. Hence, the prospect of newly developed forming approaches will be discussed.
Simon Opel - One of the best experts on this subject based on the ideXlab platform.
-
fundamental investigations on the material flow at combined Sheet and bulk metal forming processes
2011Co-Authors: Marion Merklein, J Koch, Simon OpelAbstract:Abstract The class of combined Sheet and bulk metal forming (SBMF) processes denotes the forming of Sheet metals with typical bulk forming operations. As a consequence, simultaneous 2D and 3D stress and strain states are present. Furthermore the local shape elements formed out of the Sheet plane are in the magnitude of the Sheet Thickness. This paper deals with process combinations upsetting/lateral extrusion and deep drawing/upsetting. It has been shown that an insufficient mould filling is nearly inevitable using conventional tooling systems. Hence, the prospect of newly developed forming approaches will be discussed.
Dungan Wang - One of the best experts on this subject based on the ideXlab platform.
-
geometric functions of stress intensity factor solutions for spot welds in lap shear specimens
2005Co-Authors: Dungan WangAbstract:In this paper, the stress intensity factor solutions for spot welds in U-shape specimens are investigated by finite element analyses. Three-dimensional finite element models are developed for U-shape specimens to obtain accurate stress intensity factor solutions. In contrast to the existing investigations of the stress intensity factor solutions based on the finite element analyses, various ratios of the Sheet Thickness, half specimen width, half specimen length, and corner radius to the nugget radius are considered in this investigation. The computational results confirm the functional dependence on the nugget radius and Sheet Thickness of Zhang’s analytical solutions. The computational results provide a geometric function in terms of the normalized half specimen width, normalized half specimen length, and normalized corner radius to Zhang’s analytical solutions. The computational results also provide a geometric function in terms of the aspect ratio of the specimen to complete Lin and Pan’s analytical solution. Finally, based on the analytical and computational results, the dimensions of U-shape specimens are suggested.
Andrew Ball - One of the best experts on this subject based on the ideXlab platform.
-
influence of Sheet Thickness on fatigue behavior and fretting of self piercing riveted joints in aluminum alloy 5052
2015Co-Authors: Lun Zhao, Baoying Xing, Andrew BallAbstract:Abstract This article deals mainly with the influence of Sheet Thickness on the fatigue behavior and fretting of single-lap self-piercing riveted joints in aluminum alloy 5052. The fatigue lives, failure modes, failure positions, fretting and fretting failure mechanism of the joints were investigated. A statistical analysis was performed to analyze the rationality of fatigue test data. The results showed that the fatigue life of the joints increases with increasing Sheet Thickness, but the increase of the fatigue life is limited. And, with increasing Sheet Thickness the fatigue failure positions transferred from the pierced Sheet to the locked Sheet. In all the joints fretting resulted in the initiation and propagation of fatigue cracks at the interfaces. Increasing Sheet Thickness could decrease the size and degree of fretting at the interface between the two riveted Sheets.
Guanlong Chen - One of the best experts on this subject based on the ideXlab platform.
-
the stiffness and buckling behavior of panels with stamping induced imperfections
2011Co-Authors: Hongqing Shen, Shuhui Li, Guanlong ChenAbstract:With the decrease of Sheet Thickness, the stiffness and buckling behavior of automobile body panel are more and more concerned. In this paper, the stiffness and buckling behavior of panels with stamping-induced imperfection is studied. Imperfections caused in drawing and springback are obtained by finite element analysis and introduced to define the initial state of the panel before indenting. The indenting procedure is simulated in ABAQUS Standard. In order to solve the buckling problem, a viscous pressure that is proportional to the relative velocity between surfaces is added artificially. For comparison, a simplified model in which imperfections are not considered is also established. Comparing the simulation results with the reference experiment, we find that the stamping-induced imperfections lead to a more severe oil canning phenomena under a buckling load, although they increase panel’s initial stiffness a bit. Moreover, among all stamping-induced imperfections, the geometrical imperfection (surface deflection) is beneficial to increase panel’s buckling load, and the material imperfections (residual stress and uneven Thickness) help to decrease panel’s buckling load and can make oil canning more severe during post-buckling. Influences of blank holder force, Sheet Thickness and material property on panel stiffness and buckling behavior are also studied. The work of this paper is beneficial to processing optimization, material selection, and reinforcement design for automotive exterior panels.
-
an experimental investigation on critical specimen sizes of high strength steels dp600 in resistance spot welding
2008Co-Authors: Honggang Yang, Yansong Zhang, Xinmin Lai, Guanlong ChenAbstract:Because of good combination of high strength and ductility, high strength steels (HSS) have been increasingly utilized by automotive companies, especially the DP steels. In the present paper, different weld length of the elliptical nugget for DP600 resistance spot welding was realized through modified electrode tips. Then the relationship between the weld length and critical specimen sizes, including specimen width and Sheet Thickness, was investigated through analyzing the failure modes in tensile-shear testing using statistical method. The results showed that the weld length, specimen width and Sheet Thickness had great effect on the failure modes of tensile testing specimen. And the critical specimen width, Sheet Thickness and tensile-shear strength were all linearly increased with weld length. The research results can provide a guideline for tensile-shear testing analysis and for spot welds structure design.
