Time efficient simulation to identify distortion and to locate residual stresses in large workpieces manufactured by LMD-CLAD process (Conference Presentation)

History Reduction by Lumping for Time-Efficient Simulation of Additive Manufacturing

Metals ◽

10.3390/met10010058 ◽

2019 ◽

Vol 10 (1) ◽

pp. 58 ◽

Cited By ~ 2

Author(s):

Andreas Malmelöv ◽

Andreas Lundbäck ◽

Lars-Erik Lindgren

Keyword(s):

Finite Element ◽

Additive Manufacturing ◽

Residual Stresses ◽

Energy Deposition ◽

Computation Time ◽

Layer By Layer ◽

Efficient Simulation ◽

Computational Welding Mechanics ◽

Directed Energy ◽

Short Time

Additive manufacturing is the process by which material is added layer by layer. In most cases, many layers are added, and the passes are lengthy relative to their thicknesses and widths. This makes finite element simulations of the process computationally demanding owing to the short time steps and large number of elements. The classical lumping approach in computational welding mechanics, popular in the 80s, is therefore, of renewed interest and is evaluated in this work. The method of lumping means that welds are merged. This allows fewer time steps and a coarser mesh. It was found that the computation time can be reduced considerably, with retained accuracy for the resulting temperatures and deformations. The residual stresses become, to a certain degree, smaller. The simulations were validated against a directed energy deposition (DED) experiment with alloy 625.

Download Full-text

Method to evaluate residual stresses in the laser cutting process

Lasers in Engineering ◽

10.1080/08981500290022752 ◽

2002 ◽

Vol 12 (1) ◽

pp. 27-41 ◽

Cited By ~ 7

Author(s):

Y. Zamachtchikov ◽

F. Breaban ◽

P. Vantomme ◽

A. Deffontaine

Keyword(s):

Residual Stresses ◽

Laser Cutting ◽

Cutting Process

Download Full-text

Prediction of residual stresses and springback after bending of a textured aluminium plate

Journal de Physique IV (Proceedings) ◽

10.1051/jp4:20030185 ◽

2003 ◽

Vol 105 ◽

pp. 175-182 ◽

Cited By ~ 2

Author(s):

L. Delannay ◽

R. E. Logé ◽

Y. Chastel ◽

P. Van Houtte

Keyword(s):

Residual Stresses

Download Full-text

Reconstruction of complex shaped crack from ECT signals based on a fast forward solver using an advanced multi-media element

International Journal of Applied Electromagnetics and Mechanics ◽

10.3233/jae-209372 ◽

2020 ◽

Vol 64 (1-4) ◽

pp. 621-629

Author(s):

Yingsong Zhao ◽

Cherdpong Jomdecha ◽

Shejuan Xie ◽

Zhenmao Chen ◽

Pan Qi ◽

...

Keyword(s):

Coefficient Matrix ◽

Crack Edge ◽

Numerical Accuracy ◽

Gauss Point ◽

Current Testing ◽

Efficient Simulation ◽

Shaped Crack ◽

Multi Media ◽

Profile Reconstruction ◽

Crack Profile

In this paper, the conventional database type fast forward solver for efficient simulation of eddy current testing (ECT) signals is upgraded by using an advanced multi-media finite element (MME) at the crack edge for treating inversion of complex shaped crack. Because the analysis domain is limited at the crack region, the fast forward solver can significantly improve the numerical accuracy and efficiency once the coefficient matrices of the MME can be properly calculated. Instead of the Gauss point classification, a new scheme to calculate the coefficient matrix of the MME is proposed and implemented to upgrade the ECT fast forward solver. To verify its efficiency and the feasibility for reconstruction of complex shaped crack, several cracks were reconstructed through inverse analysis using the new MME scheme. The numerical results proved that the upgraded fast forward solver can give better accuracy for simulating ECT signals, and consequently gives better crack profile reconstruction.

Download Full-text

Theoretical study of the prestressing strand's stress by computer modeling methods

Ferrous Metallurgy Bulletin of Scientific Technical and Economic Information ◽

10.32339/0135-5910-2020-111-1139-1148 ◽

2020 ◽

Vol 76 (11) ◽

pp. 1139-1148

Author(s):

A. G. Korchunov ◽

E. M. Medvedeva ◽

E. M. Golubchik

Keyword(s):

Residual Stresses ◽

High Strength ◽

Pearlitic Steel ◽

Internal Stresses ◽

Steel Microstructure ◽

Compressive Stresses ◽

Wide Range ◽

Prestressing Strands ◽

Increasing Temperature ◽

Wire Strand

The modern construction industry widely uses reinforced concrete structures, where high-strength prestressing strands are used. Key parameters determining strength and relaxation resistance are a steel microstructure and internal stresses. The aim of the work was a computer research of a stage-by-stage formation of internal stresses during production of prestressing strands of structure 1х7(1+6), 12.5 mm diameter, 1770 MPa strength grade, made of pearlitic steel, as well as study of various modes of mechanical and thermal treatment (MTT) influence on their distribution. To study the effect of every strand manufacturing operation on internal stresses of its wires, the authors developed three models: stranding and reducing a 7-wire strand; straightening of a laid strand, stranding and MTT of a 7-wire strand. It was shown that absolute values of residual stresses and their distribution in a wire used for strands of a specified structure significantly influence performance properties of strands. The use of MTT makes it possible to control in a wide range a redistribution of residual stresses in steel resulting from drawing and strand laying processes. It was established that during drawing of up to 80% degree, compressive stresses of 1100-1200 MPa degree are generated in the central layers of wire. The residual stresses on the wire surface accounted for 450-500 MPa and were tension in nature. The tension within a range of 70 kN to 82 kN combined with a temperature range of 360-380°С contributes to a two-fold decrease in residual stresses both in the central and surface layers of wire. When increasing temperature up to 400°С and maintaining the tension, it is possible to achieve maximum balance of residual stresses. Stranding stresses, whose high values entail failure of lay length and geometry of the studied strand may be fully eliminated only at tension of 82 kN and temperature of 400°С. Otherwise, stranding stresses result in opening of strands.

Download Full-text