Numerical modeling of hybrid laser welding taking into account phase change of material

2017 ◽  
Vol 36 (2) ◽  
pp. 417-426 ◽  
Author(s):  
Ivo Doležel ◽  
Václav Kotlan ◽  
Roman Hamar ◽  
David Pánek
Keyword(s):  
Laser Beam ◽  
Laser Welding ◽  
Phase Change ◽  
3D Model ◽  
Three Dimensional ◽  
Physical Parameters ◽  
Saturation Curve ◽  
Plasma Cloud ◽  
Content Type ◽  
Liquid Phases

Purpose This paper aims to present a three-dimensional (3D) model of hybrid laser welding of a steel plate. Before welding, the plate is pre- and/or post-heated by induction to avoid mechanical stresses in material due to high gradients of temperature. Welding itself is realized by laser beam without welding rod. The model takes into account existence of both solid and liquid phases in the weld. Design/methodology/approach Presented is the complete mathematical model of the above heat treatment process, taking into account all relevant nonlinearities (saturation curve of the processed steel material and temperature dependences of its physical parameters). Its numerical solution is realized by the finite element method. Some important results are compared with experimental data. Findings In comparison with the former model developed by the authors that did not take into account the phase change, the results are more realistic and exhibit a better accordance with measurements. On the other hand, they strongly depend on sufficiently accurate knowledge of material parameters in both solid and liquid levels (that represent the input data). Research limitations/implications The quality of calculated results strongly depends on the material properties and their temperature dependencies. In case of alloys (whose chemical composition may vary in some range), such data are often unavailable and must be estimated on the basis of experiments. Another quantity that has to be calibrated is the time dependence of power delivered by the laser beam, which is due to the production of a plasma cloud above the exposed spot. Practical implications The presented model and methodology of its solution may represent a basis for design of the complete technology of laser welding with induction pre-heating and/or post-heating. Originality/value Fully 3D model of hybrid laser welding (supplemented with pre- and/or post-heating by magnetic induction) taking into account both solid and liquid phases of welded metal and influence of the plasma cloud is presented.

Three-dimensional computational study in a corrugated pipe inserted system filled with phase change material

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Ömer Akbal ◽  
Hakan F. Öztop ◽  
Nidal H. Abu-Hamdeh
Keyword(s):  
Phase Change ◽  
Phase Change Material ◽  
Computational Analysis ◽  
Computational Study ◽  
Three Dimensional ◽  
Simple Algorithm ◽  
Melting Time ◽  
Geometrical Parameters ◽  
Content Type ◽  
Change Material

Purpose The purpose of this paper is to make a three-dimensional computational analysis of melting in corrugated pipe inserted system filled with phase change material (PCM). The system was heated from the inner pipe, and temperature of the outer pipe was lower than that of inner pipe. Different geometrical ratio cases and two different temperature differences were tested for their effect on melting time. Design/methodology/approach A computational analysis through a pipe with corrugated pipe filled with PCM is analyzed. Finite volume method was applied with the SIMPLE algorithm method to solve the governing equations. Findings The results indicate that the geometrical parameters can be used to control the melting time inside the heat exchanger which, in turn, affect the energy efficiency. The fastest melting time is seen in Case 4 at the same temperature difference which is the major observation of the current work. Originality/value Originality of this work is to perform a three-dimensional analysis of melting of PCM in a corrugated pipe inserted pipe.

A three-dimensional computational analysis of ellipsoidal radiator with phase change

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Nidal H. Abu-Hamdeh ◽  
Ömer Akbal ◽  
Hakan F. Öztop ◽  
Abdullah M. Abusorrah ◽  
Mohannad M. Bayoumi
Keyword(s):  
Phase Change ◽  
Temperature Difference ◽  
Computational Analysis ◽  
Three Dimensional ◽  
Time Step ◽  
Content Type ◽  
Melting Fraction ◽  
Higher Temperature ◽  
Volume Method ◽  
Change Material

Purpose The purpose of this paper is to solve the problem of a three-dimensional computational analysis for an elliptic-shaped cavity in a pipe under constant temperature. Design/methodology/approach The three-dimensional computational solution of governing equations was performed by using finite volume method with different temperature difference. Findings The parafin wax was chosen as a phase change material (PCM), and melting fraction, streamlines and isotherms are formed for different time step. It is found that position B give better results than that of position A, and temperature difference effects the duration of melting of PCM. Originality/value The three-dimensional analysis of melting in an ellipsoidal pipe with inner pipe with higher temperature is the main originality of this work.

Models partition for 3D printing objects using skeleton

2017 ◽  
Vol 23 (1) ◽  
pp. 54-64 ◽  
Author(s):  
Xiaotong Jiang ◽  
Xiaosheng Cheng ◽  
Qingjin Peng ◽  
Luming Liang ◽  
Ning Dai ◽  
...  
Keyword(s):  
3D Model ◽  
Three Dimensional ◽  
Principal Component ◽  
3D Models ◽  
Sweep Method ◽  
Final Model ◽  
Content Type ◽  
Working Volume ◽  
Minima Rule ◽  
The Greedy Algorithm

Purpose It is a challenge to print a model with the size that is larger than the working volume of a three-dimensional (3D) printer. The purpose of this paper is to present a feasible approach to divide a large model into small printing parts to fit the volume of a printer and then assemble these parts into the final model. Design/methodology/approach The proposed approach is based on the skeletonization and the minima rule. The skeleton of a printing model is first extracted using the mesh contraction and the principal component analysis. The 3D model is then partitioned preliminarily into many smaller parts using the space sweep method and the minima rule. The preliminary partition is finally optimized using the greedy algorithm. Findings The skeleton of a 3D model can effectively represent a simplified version of the geometry of the 3D model. Using a model’s skeleton to partition the model is an efficient way. As it is generally desirable to have segmentations at concave creases and seams, the cutting position should be located in the concave region. The proposed approach can partition large models effectively to well retain the integrity of meaningful parts. Originality/value The proposed approach is new in the rapid prototyping field using the model skeletonization and the minima rule. Based on the authors’ knowledge, there is no method that concerns the integrity of meaningful parts for partitioning. The proposed method can achieve satisfactory results by the integrity of meaningful parts and assemblability for most 3D models.

Inverse technique for determining temperature dependence of material properties

2017 ◽  
Vol 36 (2) ◽  
pp. 427-435
Author(s):  
David Pánek ◽  
Václav Kotlan ◽  
Roman Hamar ◽  
Ivo Doležel
Keyword(s):  
Inverse Problem ◽  
Temperature Dependence ◽  
Material Parameter ◽  
Physical Parameters ◽  
Saturation Curve ◽  
Temperature Dependent ◽  
Content Type ◽  
Steel Material ◽  
Temperature Dependences ◽  
Accuracy Of Results

Purpose This paper aims to present a methodology of finding temperature dependencies of selected physical parameters of metals. The method is based on the combination of measurement of the surface temperature of material during the process of heating and subsequent solution of the inverse problem using multi-parametric optimization. Design/methodology/approach The methodology is based on measurements and numerical solution of the forward and inverse problem, taking into account all involved nonlinearities (saturation curve of the processed steel material and temperature dependences of its physical parameters). The inverse problem is solved by a genetic algorithm. Findings The suggested methodology was successfully verified on several metal materials whose temperature-dependent parameters are known. The calculated and measured results exhibit a very good accordance (the differences do not exceed about 10 per cent for room and higher temperatures). Research limitations/implications At this moment, the methodology successfully works when the temperature dependence of just one material parameter is to be found (which means that the temperature dependencies of other parameters are known). The accuracy of results also depends on the correctness of other input data. Practical implications This paper provides a relatively easy possibility of finding the temperature dependencies of thermal conductivity or heat capacity of various alloys. Originality/value The paper proposes a methodology of finding the temperature dependence of a given material parameter that is not known in advance (which is of great importance in case of alloys).

Transient, Three-Dimensional Numerical Model of a Laser Cutting Process With Phase Change Consideration

2004 ◽  
Author(s):  
Gustavo Gutie´rrez ◽  
Juan Guillermo Araya
Keyword(s):  
Temperature Field ◽  
Laser Beam ◽  
Phase Change ◽  
Numerical Models ◽  
Three Dimensional ◽  
Phase Changes ◽  
Ceramic Surface ◽  
Numerical Predictions ◽  
Physical Shape ◽  
Finite Volume Approach

Phase change problems are encountered in several manufacturing and material processing applications. Such problems are computationally challenging because it is necessary to solve a non-linear heat conduction equation and take into considerations the conditions needed to produce material ablation, varying continuously the heat source position, thermo physical properties and physical shape of the domain. This research presents a numerical simulation of the temperature field and the removed material resulting from the impingement of a moving laser beam on a ceramic surface. A finite volume approach has been developed to predict the temperature field including phase changes generated during the process. The model considers heat losses by convection and radiation due to the high temperatures involved and uses a coordinate system affixed to the workpiece; therefore no quasi-steady conditions are assumed, as in the majority of previous works. Numerical predictions were compared with former three-dimensional numerical models considering a semi-infinite solid and from experimental data found in the literature. This study gives insight into the interactions between the laser beam and a silicon nitride workpiece during the cutting.

Hybrid realization of fillet weld

2018 ◽  
Vol 37 (4) ◽  
pp. 1315-1327 ◽  
Author(s):  
Václav Kotlan ◽  
Roman Hamar ◽  
Lenka Šroubová ◽  
Ivo Doležel
Keyword(s):  
Laser Beam ◽  
Welding Process ◽  
Physical Parameters ◽  
Additional Material ◽  
Content Type ◽  
Heating And Cooling ◽  
Proposed Model ◽  
Materials Used ◽  
Physical Phenomena ◽  
Welding Processes

Purpose A model of hybrid fillet welding is built and solved. No additional material (welding rod, etc.) is used. Heating of the welded parts is realized by laser beam with induction preheating and/or postheating. The purpose of these operations is to reduce the temperature gradient in welded parts in the course of both heating and cooling, which reduces the resultant hardness of the weld and its neighborhood and also reduces undesirable internal mechanical strains and stresses in material. Design/methodology/approach The complete mathematical model of the combined welding process is presented, taking into account all relevant nonlinearities. The model is then solved numerically by the finite element method. The methodology is illustrated with an example, the results of which are compared with experiment. Findings The proposed model provided satisfactory results even when some subtle phenomena were not taken into account (flow of melt in the pool after irradiation of the laser beam driven by the buoyancy and gravitational forces and evaporation of molten metal and influence of plasma cloud above the irradiated spot). Research limitations/implications Accuracy of the results depends on the accuracy of physical parameters of materials entering the model and their temperature dependencies. These quantities are functions of chemical composition of the materials used, and may more or less differ from the values delivered by manufacturers. Also, the above subtle physical phenomena exhibit stochastic character and their modeling may be accompanied by non-negligible uncertainties. Practical implications The presented model and methodology of its solution may represent a basis for design of welding processes in various branches of industry. Originality/value The model of a complex multiphysics problem (induction-assisted laser welding) provides reasonable results confirmed by experiments.

Thermal Defocussing Criteria for a Laser Welding Process

2004 ◽  
Author(s):  
Gregory J. Kowalski ◽  
Richard A. Whalen
Keyword(s):  
Laser Beam ◽  
Laser Welding ◽  
Phase Change ◽  
Heat Affected Zone ◽  
Solid Phase ◽  
Welding Process ◽  
Index Of Refraction ◽  
Simulation Code ◽  
Collimated Beam ◽  
Laser Welding Process

A numerical simulation code is developed to study the significance of refraction effects (beam self-focussing or defocussing) of a laser during a laser welding process. Relationships between the size of the heat affected zone (HAZ), the melt zone and the laser beam parameters are investigated for a short pulsed laser welding process. The solution method includes the thermally stimulated nonlinear optical effects caused by the temperature dependent index of refraction, as well as the step change in surface reflection that occurs due to the liquid and solid phase change. The interaction of these parameters is investigated to better control the laser manufacturing processes. Difficulties of numerical modeling and the tradeoff between using small nodes to reduce the sawtooth behavior in the phase change model and computer run times that are consistent with real time control are discussed. The results indicate that there are no significant refraction affects of the laser beam and that the heat affected zone is approximately 6% larger for a collimated beam input as compared to a gaussian beam input. Peak temperatures are lower for the collimated beam.

scholarly journals 3D textile reconstruction based on KinectFusion and synthesized texture

2017 ◽  
Vol 29 (6) ◽  
pp. 793-806 ◽  
Author(s):  
PengPeng Hu ◽  
Taku Komura ◽  
Duan Li ◽  
Ge Wu ◽  
Yueqi Zhong
Keyword(s):  
Artificial Intelligence ◽  
Design Methodology ◽  
3D Model ◽  
Three Dimensional ◽  
Experimental Results ◽  
High Quality ◽  
Content Type

Purpose The purpose of this paper is to present a novel framework of reconstructing the 3D textile model with synthesized texture. Design/methodology/approach First, a pipeline of 3D textile reconstruction based on KinectFusion is proposed to obtain a better 3D model. Second, “DeepTextures” method is applied to generate new textures for various three-dimensional textile models. Findings Experimental results show that the proposed method can conveniently reconstruct a three-dimensional textile model with synthesized texture. Originality/value A novel pipeline is designed to obtain 3D high-quality textile models based on KinectFusion. The accuracy and robustness of KinectFusion are improved via a turntable. To the best of the authors’ knowledge, this is the first paper to explore the synthesized textile texture for the 3D textile model. This is not only simply mapping the texture onto the 3D model, but also exploring the application of artificial intelligence in the field of textile.

A new similarity solution with stability analysis for the three-dimensional boundary layer of hybrid nanofluids

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Najiyah Safwa Khashi'ie ◽  
Norihan M. Arifin ◽  
Ioan Pop ◽  
Roslinda Nazar ◽  
Ezad Hafidz Hafidzuddin
Keyword(s):  
Boundary Layer ◽  
Stability Analysis ◽  
Differential Equations ◽  
Similarity Transformation ◽  
Three Dimensional ◽  
Physical Parameters ◽  
Hybrid Nanofluid ◽  
Content Type ◽  
Boundary Layer Equations ◽  
Dimensional Boundary

Purpose The purpose of this study is to implement a new class of similarity transformation in analyzing the three-dimensional boundary layer flow of hybrid nanofluid. The Cu-Al2O3/water hybrid nanofluid is formulated using the single-phase nanofluid model with modified thermophysical properties. Design/methodology/approach The governing partial differential equations are reduced to the ordinary (similarity) differential equations using the proposed similarity transformation. The resulting equations are programmed in Matlab software through the bvp4c solver to obtain their solutions. The features of the reduced skin frictions and the velocity profiles for different values of the physical parameters are analyzed and discussed. Findings The non-uniqueness of the solutions is observed for certain physical parameters. The dual solutions are perceived for both permeable and impermeable cases and being the main agenda of the work. The execution of stability analysis proves that the first solution is undoubtedly stable than the second solution. An increase in the mass transpiration parameter leads to the uniqueness of the solution. Oppositely, as the injection parameter increase, the two solutions remain. However, no separation point is detected in this problem within the considered parameter values. The present results are decisive to the pair of alumina and copper only. Originality/value The present findings are original and can benefit other researchers particularly in the field of fluid dynamics. This study can provide a different insight of the transformation that is applicable to reduce the complexity of the boundary layer equations.

Quality analysis using three-dimensional modelling and image processing techniques

2019 ◽  
Vol 19 (4) ◽  
pp. 614-628 ◽  
Author(s):  
Mohamed Marzouk ◽  
Mahmoud Hassouna
Keyword(s):  
Image Processing ◽  
3D Model ◽  
Median Filter ◽  
Mean Shift ◽  
Three Dimensional ◽  
Wiener Filter ◽  
Quality Analysis ◽  
Split Bregman ◽  
Specific Element ◽  
Content Type

Purpose This paper aims to propose a system for defect detection in constructed elements that is able to indicate deformity positions. It also evaluates the defects in finishing materials of constructed building elements to support the subjective visual quality investigation of the aesthetics of an architectural work. Design/methodology/approach This strategy depends on defect features analysis that evaluates the defect value in digital images using digital image processing methods. The research uses the three-dimensional (3D) modeling techniques and image processing algorithms to generate a system that is able to perform some of the monitoring activities by computers. Based on the collected site scans, a 3D model is created for the building. Then, several images can be exported from the 3D model to investigate a specific element. Different image denoizing techniques are compared such as mean filter, median filter, Wiener filter and Split–Bregman iterations. The most efficient technique is implemented in the system. Then, the following six different methods are used for image segmentation to separate the concerned object from the background; color segmentation, region growing segmentation, histogram segmentation, local standard deviation segmentation, adaptive threshold segmentation and mean-shift cluster segmentation. Findings The proposed system is able to detect the cracks and defected areas in finishing works and calculate the percentage of the defected area compared to the total captured area in the photo with high accuracy. Originality/value The proposed system increases the precision of decision-making by decreasing the contribution of human subjective judgment. Investigation of different finishing surfaces is applied to validate the proposed system.

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