Experimental and Numerical Study of the LENS Rapid Fabrication Process

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Liang Wang ◽  
Sergio D. Felicelli ◽  
James E. Craig
Keyword(s):  
Temperature Distribution ◽  
Process Parameters ◽  
Molten Pool ◽  
Numerical Study ◽  
Three Dimensional ◽  
Element Model ◽  
Pool Size ◽  
Depth Direction ◽  
Net Shaping ◽  
Three Dimensional Finite Element

Several aspects of the thermal behavior of deposited stainless steel 410 (SS410) during the laser engineered net shaping (LENS™) process were investigated experimentally and numerically. Thermal images in the molten pool and surrounding area were recorded using a two-wavelength imaging pyrometer system, and analyzed using THERMAVIZ™ software to obtain the temperature distribution. The molten pool size, temperature gradient, and cooling rate were obtained from the recorded history of temperature profiles. The dynamic shape of the molten pool, including the pool size in both travel direction and depth direction was investigated, and the effect of different process parameters was illustrated. The thermal experiments were performed in a LENS™ 850 machine with a 3 kW IPG Photonics laser for different process parameters. A three-dimensional finite element model was developed to calculate the temperature distribution in the LENS™ process as a function of time and process parameters. The modeling results showed good agreement with the experimental data.

Process Modeling in Laser Deposition of Multilayer SS410 Steel

2007 ◽  
Vol 129 (6) ◽  
pp. 1028-1034 ◽  
Author(s):  
Liang Wang ◽  
Sergio Felicelli
Keyword(s):  
Phase Transformation ◽  
Temperature Distribution ◽  
Three Dimensional ◽  
Element Model ◽  
Traverse Speed ◽  
Processing Parameters ◽  
Dimensional Finite Element ◽  
Net Shaping ◽  
Three Dimensional Finite Element ◽  
Continuous Cooling Transformation Diagram

A three-dimensional finite element model was developed to predict the temperature distribution and phase transformation in deposited stainless steel 410 (SS410) during the Laser Engineered Net Shaping (LENS™) rapid fabrication process. The development of the model was carried out using the SYSWELD software package. The model calculates the evolution of temperature in the part during the fabrication of a SS410 plate. The metallurgical transformations are taken into account using the temperature-dependent material properties and the continuous cooling transformation diagram. The ferritic and martensitic transformation as well as austenitization and tempering of martensite are considered. The influence of processing parameters such as laser power and traverse speed on the phase transformation and the consequent hardness are analyzed. The potential presence of porosity due to lack of fusion is also discussed. The results show that the temperature distribution, the microstructure, and hardness in the final part depend significantly on the processing parameters.

Numerical Study of Welding Sequence on the Residual Stress Field in a Thick-Walled Tee Joint

2011 ◽  
Vol 219-220 ◽  
pp. 1211-1214
Author(s):  
Wei Jiang
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Numerical Study ◽  
Three Dimensional ◽  
Element Model ◽  
Residual Stress Field ◽  
Factors Affecting ◽  
Welding Sequence ◽  
Welding Sequences ◽  
Three Dimensional Finite Element

Finite element simulation is an efficient method for studying factors affecting weld-induced residual stress distributions. In this paper, a validated three-dimensional finite element model consisting of sequentially coupled thermal and structural analyses was developed. Three possible symmetrical welding sequences, i.e. one-welder, two-welder and four-welder sequence, which were perceived to generate the least distortion in actual welding circumstances, were proposed and their influences on the residual stress fields in a thick-walled tee joint were investigated. Appropriate conclusions and recommendations regarding welding sequences are presented.

Study of arching behaviour and strength of concrete masonry infills under out-of-plane loading

2019 ◽  
Vol 46 (10) ◽  
pp. 896-908 ◽  
Author(s):  
Ehsan Nasiri ◽  
Yi Liu
Keyword(s):  
Numerical Study ◽  
Three Dimensional ◽  
Element Model ◽  
Contributing Factors ◽  
Concrete Frames ◽  
Masonry Infills ◽  
Concrete Masonry ◽  
Wide Range ◽  
Out Of Plane ◽  
Three Dimensional Finite Element

A numerical study using a three-dimensional finite element model was conducted to investigate the arching behaviour and strength of concrete masonry infills bounded by reinforced concrete frames subjected to out-of-plane loading. Physical specimens were concurrently tested to provide results for validation of the model as well as evidence of directional characteristics of arching behaviour of masonry infills. A subsequent parametric study using the model included a wide range of infilled frame geometric properties. The results showed in detail the difference in one-way and two-way arching in terms of both strength and failure mechanism, and the contributing factors to this difference. Evaluation of the two main design equations for out-of-plane strength of masonry infills led to proposal of modifications to provide a more rational consideration of directional behaviour of concrete masonry infills. A comparison study using the available test results showed a marked improvement of strength prediction based on the proposed modification.

scholarly journals Simulation study on modified coil configuration used for shrink fitting of semi-built-up crankshaft and parameters influencing the thermal distribution

2020 ◽  
Vol 103 (4) ◽  
pp. 003685042096785
Author(s):  
Jianguo Duan ◽  
Qinglei Zhang ◽  
Xintao Long ◽  
Kebin Zhang
Keyword(s):  
Temperature Distribution ◽  
Induction Heating ◽  
Three Dimensional ◽  
Element Model ◽  
Heating Process ◽  
Current Frequency ◽  
Dimensional Finite Element ◽  
Shrink Fitting ◽  
Three Dimensional Finite Element

Semi-built-up crankshafts are universally manufactured by shrink-fitting process with induction heating device. The configurations of induction coil have a great impact on the distributions of eddy current and temperature of crankthrows. Most induction devices are apt to cause some undesirable phenomena such as uneven temperature distribution and irregular deformation after induction heating. This article proposes a modified configuration of induction heating coil according to the crankthrow geometry. By combining the heat conduction equation and the heat boundary conditions, a three-dimensional finite element model, which takes into account the nonlinearity of the material’s electromagnetic and thermal physical properties in the heating process, was developed. The influence of several parameters, such as position and curvature of the arc coil, the current frequency and density, coaxiality of crankweb hole and coil, influencing the temperature distribution inside the crankthrow was also analyzed. The comparison with the numerical simulation results of the original configuration indicates that the modified configuration has better adaptability to the crankthrow. Also, it can help to improve the temperature distribution, and reduce the deformation of the shrink-fitting hole. This exploration provide an effective way for the enterprise to further enhance the shrink-fitting quality of crankshaft.

Numerical Study on the Effect of Twin-Tube Shield Excavation on Adjacent Pipelines

2012 ◽  
Vol 170-173 ◽  
pp. 1491-1496 ◽  
Author(s):  
Xin Wang ◽  
De Shen Zhao ◽  
Meng Lin Xu
Keyword(s):  
Distribution Curve ◽  
Numerical Study ◽  
Three Dimensional ◽  
Element Model ◽  
Stress Release ◽  
Tunnel Excavation ◽  
Normal Distribution Curve ◽  
Numerical Result ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element

Based on Dalian subway line 2 from Chun-guang street station to Xiang-gong street station,the three dimensional finite element model was established using FLAC3D software , the shield excavated surface against the pressure, the stress release, the shield tail escape and grouting. The numerical result indicated that the pipeline displacement increases gradually with the advance of the tunnel excavation. When one-sided tunnel excavation is carried out, the largest displacement is located at the tunnel axis, the settling curve basically conforms to the normal distribution curve with the unimodal characteristic. The excavation of right-side tunnel is disadvantageous to the left-side tunnel. The analysis indicated that the pipeline is in a secure state. The work in this paper provided theoretical basis and the practical guidance to this project.

Comparison of Two-Dimensional and Three-Dimensional Thermal Models of the LENS® Process

2008 ◽  
Vol 130 (10) ◽  
Author(s):  
H. Yin ◽  
L. Wang ◽  
S. D. Felicelli
Keyword(s):  
Thermal Behavior ◽  
Molten Pool ◽  
3D Model ◽  
Dynamic Control ◽  
Three Dimensional ◽  
Element Model ◽  
Two Dimensional ◽  
3D Effects ◽  
Net Shaping ◽  
2D Model

A new two-dimensional (2D) transient finite element model was developed to study the thermal behavior during the multilayer deposition by the laser engineered net shaping rapid fabrication process. The reliability of the 2D model was evaluated by comparing the results obtained from the 2D model with those computed by a previously developed three-dimensional (3D) model. It is found that the predicted temperature distributions and the cooling rates in the molten pool and its surrounding area agree well with the experiment data available in literature and with the previous results calculated with the 3D model. It is also concluded that, for the geometry analyzed in this study, the 2D model can be used with good accuracy, instead of the computationally much more expensive 3D model, if certain precautions are taken to compensate for the 3D effects of the substrate. In particular, a 2D model could be applied to an in situ calculation of the thermal behavior of the deposited part during the fabrication, allowing dynamic control of the process. The 2D model is also applied to study the effects of substrate size and idle time on the thermal field and size of the molten pool.

A Combined Experimental and Numerical Study of the Effect of Surface Roughness on Nanoindentation

2019 ◽  
Vol 11 (07) ◽  
pp. 1950070
Author(s):  
M. Nazemian ◽  
M. Chamani ◽  
M. Baghani
Keyword(s):  
Thin Films ◽  
Surface Roughness ◽  
Finite Element ◽  
Rough Surface ◽  
Numerical Study ◽  
Three Dimensional ◽  
Element Model ◽  
Element Analysis ◽  
Three Dimensional Finite Element ◽  
Effect Of Surface

Gold and copper thin films are widely used in microelectromechanical system (MEMS) and nanoelectromechanical system (NEMS) devices. Nanoindentation has been developed in mechanical characterization of thin films in recent years. Several researchers have examined the effect of surface roughness on nanoindentation results. It is proved that the surface roughness has great importance in nanoindentation of thin films. In this paper, the surface topography of thin films is simulated using the extracted data from the atomic force microscopy (AFM) images. Nanoindentation on a rough surface is simulated using a three-dimensional finite-element model. The results are compared with the results of finite-element analysis on a smooth surface and the experimental results. The results revealed that the surface roughness plays a key role in nanoindentation of thin films, especially at low indentation depths. There was good compatibility between the results of finite-element simulation on the rough surface and those of experiments. It is observed that on rough films, at low indentation depths, the geometry of the location where the nanoindentation is performed is of major importance.

Experimental and numerical study of process-induced total spring-in of corner-shaped composite parts

2016 ◽  
Vol 51 (16) ◽  
pp. 2347-2361 ◽  
Author(s):  
K Furkan Çiçek ◽  
Merve Erdal ◽  
Altan Kayran
Keyword(s):  
Numerical Model ◽  
Numerical Study ◽  
Three Dimensional ◽  
Interaction Mechanism ◽  
Element Model ◽  
Shape Design ◽  
Optical Scanning ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Good Agreement

Process-induced total spring-in of corner-shaped composite parts manufactured via autoclave-forming technique using unidirectional prepreg is studied both numerically and experimentally. In the numerical study, a three-dimensional finite element model which takes into account the cure shrinkage of the resin, anisotropic material properties of the composite part and the tool-part interaction is developed. The outcome of the numerical model is verified experimentally. For this purpose, U-shaped composite parts are manufactured via autoclave-forming technique. Process-induced total spring-in, due to the combined effect of material anisotropy and tool-part interaction, at different sections of the U-shaped parts are measured with use of the combination of the three-dimensional optical scanning technique and the generative shape design. Total spring-in determined by the numerical model is found to be in good agreement with the average total spring-in measured experimentally. The effect of tool-part interaction mechanism on the total spring-in is studied separately to ascertain its effect on the total spring-in behavior clearly. It is shown that with the proper modeling of the tool-part interaction, numerically determined total spring-in approaches the experimentally determined total spring-in.

Three-dimensional finite element model to study temperature distribution in peripheral layers of human limbs immediately after physical exercise

2017 ◽  
Vol 10 (04) ◽  
pp. 1750053 ◽  
Author(s):  
Babita Kumari ◽  
Neeru Adlakha
Keyword(s):  
Finite Element ◽  
Temperature Distribution ◽  
Physical Exercise ◽  
Finite Element Model ◽  
Three Dimensional ◽  
Element Model ◽  
The Body ◽  
Dimensional Finite Element ◽  
Human Limb ◽  
Three Dimensional Finite Element

The physical exercise imposes challenges on the human thermoregulatory system, as heat exchange between the body and environment is substantially impaired, which can lead to decrease in performance and increased risk of heat illness. In view of above a three-dimensional finite element model is proposed to study the effect of different intensities of physical exercise on temperature distribution in peripheral regions of human limbs under moderate climatic conditions. Human limb is assumed to have a cylindrical cross-section. The peripheral region of the human limb is divided into three natural components, namely epidermis, dermis and subdermal tissues. The model incorporates the effect of important physiological parameters like blood mass flow rate, metabolic heat generation, and thermal conductivity of the tissues. Appropriate boundary conditions have been framed based on the physical conditions of the problem. The model is transformed into the discretized variational form and finite element method (FEM) has been employed to obtain the solution. The numerical results have been used to obtain the temperature profiles in the region immediately after exercise for an unsteady state case. The thermal information generated from the model can be useful for developing protocols for improving performance of sportsmen, military persons and labor-intensive workers.

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