Analysis on Section Effect of Heavy Plate by Finite Element Method during Controlled Cooling

2008 ◽  
Vol 575-578 ◽  
pp. 1407-1413
Author(s):  
Nan Li ◽  
Cai Fu Yang ◽  
Tao Pan
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Steel Plate ◽  
Cooling Curve ◽  
Controlled Cooling ◽  
Temperature Field Distribution ◽  
Heavy Plate ◽  
Cooling Conditions ◽  
Cooling Schedule ◽  
Element Method

ANSYS implicit finite element method (FEM) was used to simulate the process of controlled cooling of 50mm heavy plate. And the corresponding cooling curve and temperature field distribution were obtained from the calculations. The results indicated the section inhomogeneity of temperature at different place from surface to center of steel plate. Different cooling conditions were compared to analyze the effect of cooling schedule on section inhomogeneity, which could provide theoretical basis for selecting appropriate cooling schedule to alleviate the section effect.

Automatic Simulation of a Sequence of Hot-Former Forging Processes by a Rigid-Thermoviscoplastic Finite Element Method

1998 ◽  
Vol 120 (4) ◽  
pp. 291-296 ◽  
Author(s):  
M. S. Joun ◽  
H. K. Moon ◽  
Rajiv Shivpuri
Keyword(s):  
Heat Transfer ◽  
Finite Element Method ◽  
Finite Element ◽  
Analysis Model ◽  
Forging Process ◽  
Simulation Techniques ◽  
Cooling Conditions ◽  
Fully Automatic ◽  
Automatic Simulation ◽  
Element Method

A fully automatic forging simulation technique in hot-former forging is presented in this paper. A rigid-thermoviscoplastic finite element method is employed together with automatic simulation techniques. A realistic analysis model of the hot-former forging processes is given with emphasis on thermal analysis and simulation automation. The whole processes including forming, dwelling, ejecting, and transferring are considered in the analysis model and various cooling conditions are embedded in the analysis model. The approach is applied to a sequence of three-stage hot former forging process. Nonisothermal analysis results are compared with isothermal ones and the effect of heat transfer on predicted metal flows is discussed.

Study on the Section Inhomogeneity of VN Microallyed Heavy Plate during Controlled Rolling

2011 ◽  
Vol 704-705 ◽  
pp. 1416-1422 ◽  
Author(s):  
Nan Li
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Thick Plate ◽  
Physical Simulation ◽  
Controlled Rolling ◽  
Austenite Grain Size ◽  
Center Layer ◽  
Heavy Plate ◽  
Heat Preservation ◽  
Element Method

The finite element method and physical simulation were used to research the section effect of 50mm heavy plate microalloyed with VN during rolling and the effect of controlled rolling schedule on the section inhomogeneity. We can conclude from the results that when the whole reduction of the plate is constant, the increase of reduction in pass makes for the deformation conveying towards center layer of plate and reducing the section inhomogeneity. To the process that 220mm thick plate blank was rolled to 50mm thick plate, when the rolling pass decreased from 10 to 6, the accumulated deformation of the center layer was increased from 58.35% to 67.87%, and the austenite grain size decreased from 41.3μm to 35.4μm. The effect of final rolling temperature depends on the heat preservation: if there is no heat preservation there almost has no effect on the section homogeneity; if there has a suitable heat preservation, the section inhomogeneity can be reduced efficiently, and the best homogeneity can be obtained when final rolled at 870°C. Key words: heavy plate, VN microalloying, section effect, finite element method

Thermostructural Analysis of Steam Turbine in Prewarming Operation With Hot Air

2019 ◽  
Vol 141 (11) ◽  
Author(s):  
Piotr Łuczyński ◽  
Dennis Toebben ◽  
Lukas Pehle ◽  
Manfred Wirsum ◽  
Wolfgang F. D. Mohr ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Finite Element Method ◽  
Finite Element ◽  
Steam Turbine ◽  
Thermal Contact ◽  
Temperature Fields ◽  
Cooling Curve ◽  
Steam Turbines ◽  
Hot Air ◽  
Element Method

AbstractIn pursuit of flexibility improvements and extension of lifetime, a concept to prewarm steam turbines using hot air was developed. In order to further optimize the prewarming operation, an extensive numerical investigation is conducted to determine the time-dependent temperature and stress fields. In this work, the transient thermal and structural analyses of an IP 19-stage steam turbine in prewarming operation with hot air are presented. Based on the previous investigations, a hybrid finite element method (HFEM—numerical finite element method (FEM) and analytical) approach especially developed for this purpose is applied to efficiently calculate the solid body temperatures of a steam turbine in predefined prewarming scenarios. The HFEM model utilizes the Nusselt number correlations to describe the heat transfer between the hot air and the turbine components in the flow channel. These correlations were developed based on unsteady conjugate heat transfer (CHT) simulations of multistage turbine models. In addition, most of the thermal energy in turbine prewarming operation is transferred through vanes and blades. Therefore, the HFEM approach considers the thermal contact resistance (TCR) on the surfaces between vanes/casing and blades/rotor. After the calibration of the HFEM model with experimental data based on measurements of the natural cooling curve, the prewarming processes for different prewarming scenarios are simulated. Subsequently, the obtained temperature fields are imported to an FEM model in order to conduct a structural analysis, which, among other variables, includes the values and locations of highest stresses and displacements.

Prediction of Residual Stress in Multi-Pass Welded Joint Using Idealized Explicit FEM

2012 ◽  
Author(s):  
Masakazu Shibahara ◽  
Shinsuke Itoh ◽  
Takashi Okada ◽  
Kazuki Ikushima ◽  
Satoru Nishikawa
Keyword(s):  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Steel Plate ◽  
Computational Time ◽  
Processing Unit ◽  
Memory Consumption ◽  
Explicit Finite Element ◽  
Thick Steel ◽  
Element Method

Heavy thick steel plate is used for pipes and also ship structures, and multi-pass welding is usually adopted for the welding. Because of the heavy thickness, residual stress plays an important role, particularly in crack propagation. Implicit Finite Element Method (FEM) is often used as a welding analysis method to examine the residual stress of the welded plate, but it is not easily applied to multi-pass welding problems with tens of thousands of degrees of freedom, because of the huge computational time and memory consumption. Alternatively, it is possible to simulate the residual stress in shorter time with lower memory consumption by using Idealized Explicit Finite Element Method developed by the authors. Moreover, the computational time can be shortened by using Idealized Explicit FEM using a Graphics Processing Unit (GPU). In this research, Idealized Explicit FEM parallelized using a GPU is applied to the analysis of the residual stresses of the multi-pass welding joint of a pipe structure made of heavy thick steel plate. As the result, the residual stress simulated by the Idealized Explicit FEM corresponds to the measured residual stress. Furthermore, it is found that the grouping method may affect to the residual stress distribution.

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