scholarly journals Methodical procedure of virtual manufacturing for analysing WAAM distortion along with experimental verification

2021 ◽  
Vol 1 (1) ◽  
pp. 74-87
Author(s):  
Keval Priapratama Prajadhiana ◽  
Yupiter HP Manurung ◽  
Alexander Bauer ◽  
Mohamed Ackiel Mohamed
Keyword(s):  
Heat Transfer ◽  
Stainless Steel ◽  
Experimental Verification ◽  
Steel Wire ◽  
Virtual Manufacturing ◽  
Temperature History ◽  
Robotic Welding ◽  
Transfer Coefficients ◽  
Rectangular Mesh ◽  
Wire Arc Additive Manufacturing

This paper deals with a principal development of virtual manufacturing (VM) procedure to predict substrate distortion induced by Wire Arc Additive Manufacturing (WAAM) process. In this procedure, a hollow shape is designed in a thin-walled form made of stainless steel. The procedure starts with geometrical modelling of WAAM component consisting of twenty-five deposited layers with austenitic stainless-steel wire SS316L as feedstock and SS304 as substrate material. The hollow shape is modelled based on simplified rectangular mesh geometry with identical specimen dimensions during the experiment. Material model to be defined can be retrieved directly from a database or by conducting a basic experiment to obtain the evolution of material composition, characterized using Scanning Electron Microscopy (SEM) with Energy Dispersive X-ray (EDX) analysis, and generated using advanced modelling software JMATPRO for creating new properties including the flow curves. Further, a coupled thermomechanical solution is adopted, including phase-change phenomena defined in latent heat, whereby temperature history due to successive layer deposition is simulated by coupling the heat transfer and mechanical analysis. Transient thermal distribution is calibrated from an experiment obtained from thermocouple analysis at two reference measurement locations. New heat transfer coefficients are to be adjusted to reflect actual temperature change. As the following procedure prior to simulation execution, a sensitivity analysis was conducted to find the optimal number of elements or mesh size towards temperature distribution. The last procedure executes the thermomechanical numerical simulation and analysis the post-processing results. Based on all aspects in VM procedures and boundary conditions, WAAM distortion is verified using a robotic welding system equipped with a pulsed power source. The experimental substrate distortion is measured at various points before and after the process. It can be concluded based on the adjusted model and experimental verification that using nonlinear numerical computation, the prediction of substrate distortion with evolved material property of component yields far better result which has the relative error less than 11% in a comparison to database material which has 22%, almost doubled the inaccuracy.

scholarly journals Heat Transfer Enhancement by Shot Peening of Stainless Steel

Coatings ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 584
Author(s):  
Pramote Koowattanasuchat ◽  
Numpon Mahayotsanun ◽  
Sedthawatt Sucharitpwatskul ◽  
Sasawat Mahabunphachai ◽  
Kuniaki Dohda
Keyword(s):  
Heat Transfer ◽  
Surface Roughness ◽  
Stainless Steel ◽  
Process Parameters ◽  
Shot Peening ◽  
Cfd Simulation ◽  
Cost Effective ◽  
Transfer Coefficients ◽  
Roughness Effects ◽  
Heat Transfer Efficiency

In heat exchange applications, the heat transfer efficiency could be improved by surface modifications. Shot peening was one of the cost-effective methods to provide different surface roughness. The objectives of this study were (1) to investigate the influences of the surface roughness on the heat transfer performance and (2) to understand how the shot peening process parameters affect the surface roughness. The considered specimens were 316L stainless steel hollow tubes having smooth and rough surfaces. The computational fluid dynamics (CFD) simulation was used to observe the surface roughness effects. The CFD results showed that the convective heat transfer coefficients had linear relationships with the peak surface roughness (Rz). Finite element (FE) simulation was used to determine the effects of the shot peening process parameters. The FE results showed that the surface roughness was increased at higher sandblasting speeds and sand diameters.

External Forced Convection Enhancement Using a Corona Discharge

2007 ◽  
Author(s):  
David B. Go ◽  
Raul A. Maturana ◽  
Timothy S. Fisher ◽  
Suresh V. Garimella
Keyword(s):  
Heat Transfer ◽  
Flat Plate ◽  
Corona Discharge ◽  
Flow Direction ◽  
Steel Wire ◽  
Experimental Studies ◽  
Local Heat Transfer ◽  
Bulk Flow ◽  
Electrode Pair ◽  
Transfer Coefficients

An ionic wind is formed when air ions generated by a corona discharge are accelerated by an electric field and exchange momentum with neutral air molecules, causing air flow. Because ionic winds can generate flow with no moving parts, they offer an attractive method for enhancing the heat transfer from a surface that would otherwise only be cooled by natural convection and/or radiation. In the presence of an external, flat plate flow, ionic winds distort the boundary layer such that local heat transfer is enhanced at the wall, and recent work has suggested that integrating such devices can be useful for cooling electronic components locally. In this work, corona discharges are generated between a steel wire and copper tape electrode pair on a flat plate, perpendicular to the bulk flow direction such that the discharge is in the direction of the bulk flow. The corona discharge current is characterized, and a corona glow and spark discharge are visualized. Experimental studies of the heat transfer from a heated flat plate are conducted using an infrared camera which indicated both upstream and downstream cooling along the entire length of the wire. Heat transfer coefficients are increased by more than 200% above those obtained from bulk flow alone and are correlated to the fourth root of the corona current. Preliminary parametric studies demonstrate the influence of the electrode-pair configuration on the cooling enhancement and suggest improved geometric designs.

Evaporative Heat Transfer Coefficients During Sensible Heating of Milk

2015 ◽  
Vol 3 (1) ◽  
Author(s):  
Mahesh Kumar ◽  
Sudhir Kumar ◽  
Om Prakash ◽  
K. S. Kasana
Keyword(s):  
Heat Transfer ◽  
Stainless Steel ◽  
Experimental Error ◽  
Operating Temperature ◽  
Conventional Heating ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Evaporative Heat Transfer ◽  
Rate Of Heating ◽  
Evaporative Heat Transfer Coefficient

In this article, the evaporative heat transfer coefficients for sensible heating phase of milk in a stainless steel pot during khoa making by conventional heating method have been reported. Various indoor experiments were performed for sensible heating of milk in a stainless steel pot under open condition by varying heat inputs from 240 watts to 420 watts. The experimental data were used to determine the values of evaporative heat transfer coefficients which were observed to decrease with an increase in rate of heating. It is also observed that the evaporative heat transfer coefficient increases significantly with the increase in operating temperature for each rate of heat inputs. The experimental error in terms of percent uncertainty was also evaluated.

scholarly journals DETERMINING HEAT TRANSMISSION RESISTANCE OF ENCLOSING STRUCTURES

2018 ◽  
Vol 61 (1) ◽  
pp. 47-59 ◽  
Author(s):  
B. M. Khroustalev ◽  
V. D. Sizov
Keyword(s):  
Heat Transfer ◽  
Boundary Conditions ◽  
Thermal Resistance ◽  
Surface Temperature ◽  
Rate Of Change ◽  
Temperature History ◽  
Transfer Coefficients ◽  
Thermophysical Characteristics ◽  
Time Intervals ◽  
Relative Temperature

Fulfillment of the activities aimed to an increase of the thermal resistance of enclosing structures requires the determination of their thermophysical characteristics with the use of the determination method based on the solution of problems of heat conduction, establishing the con- nection between the spatial and temporal temperature changes under the effect of heat source. This work uses the solution of the problem under nonstationary heating of the enclosing structure in the form of unrestricted plate with boundary conditions of the III kind. According to the known relations and graphs alterations in surface temperature depending on warm-up time, on thermal resistance of constructions and on arguments of Fo and Bi, i. e. initial and boundary conditions are determined. The graphic dependencies that have been obtained show that the surface temperature depends on the thermal resistance, while the temperature at the opposite surface during heat expo- sure remains practically unchanged during t = 5 h. Thus, if the outside air temperature is altered, then the rate of change of surface temperature or relative temperature q make it possible to deter- mine the thermophysical characteristics by solving the inverse problem of thermal conductivity with the use of the converted ratio to determine R as a function R = f(q, t). If the constructed graphic dependencies R = f(q, t) are used at different heat transfer coefficients, then according to the measured temperatures at different time intervals it is possible to determine thermal resistance in the same time intervals and, according to their average value, determine the required resistance to heat transfer R. The estimated ratio of analytical and graphic dependencies that we have obtained demonstrate the adequacy of the conducted full-scale measurements, if the areas with homogeneous temperature field and temperature history are chosen, and they can be used in determining the heat resistance of the enclosing structure in the form of unrestricted plate with boundary conditions of the III kind.

Experimental Determination of Heat Transfer Coefficients for Forming of Stainless Steel Sheets Considering Process Conditions and Deep-Drawing Film

2013 ◽  
Vol 554-557 ◽  
pp. 1501-1508 ◽  
Author(s):  
Philipp Schmid ◽  
Mathias Liewald
Keyword(s):  
Heat Transfer ◽  
Stainless Steel ◽  
Deep Drawing ◽  
Basic Knowledge ◽  
Process Conditions ◽  
Transfer Coefficients ◽  
Heat Transfer Coefficients ◽  
Steel Sheets ◽  
Forming Tools

Heat transfer coefficients are playing an important role in forming of metastable stainless steel sheets. Metastable austenitic stainless steels are highly influenced by heating of forming tools due to generation of latent heat during forming process. Strain-induced martensite formation and hence the TRIP-effect is directly coupled with the temperature development within forming tools as well as the temperature induced by heat controlled tools. Measurements of heat development in serial deep drawing processes are showing the need for an accurate determination of heat transfer coefficients considering actual process conditions. Heat transfer coefficients were determined with a simple and easy applicable measurement device for tool materials AMPCO 25 and cold work tool steel EN 1.2379 in combination with aluminum, austenitic EN 1.4301 and ferritic EN 1.4016 stainless steel grades. Special attention was paid to production-related individual influences such as surface conditions, lubrication and deep drawing film. Experiments were accomplished between 1-15 N/mm² showing high influence of intermediate media on heat transfer between forming tool and part and serve as boundary conditions for fully thermo-mechanical coupled forming simulations. A strong influence of deep drawing film, lubrication and surface pressure on heat exchange could be determined and this basic knowledge is seen as mandatory for dimensioning of heat controlled metal forming tools. Finally the experimental determined results are discussed and compared to common heat transfer models and similar experiments from literature.

Analytical Evaluation of Weld Residual Stress Distribution for BWR Pipings

2008 ◽  
Author(s):  
M. Ando ◽  
K. Nakata ◽  
R. Sumiya ◽  
M. Itow ◽  
N. Tanaka
Keyword(s):  
Heat Transfer ◽  
Residual Stress ◽  
Stainless Steel ◽  
Material Properties ◽  
Fem Analysis ◽  
Residual Stress Distribution ◽  
Temperature History ◽  
Stress Distributions ◽  
Weld Residual Stress ◽  
Stress Analyses

SCC (stress corrosion cracking) of low-carbon stainless steel piping has been found in Japanese BWR plants since 2002. According to JSME Fitness-for-Service Code, flaw evaluations are required to verify the life-time of piping if SCC is detected. In order to evaluate the SCC propagation behavior, it is necessary to obtain the residual stress distribution through the thickness of piping. In this study, the mock-up PLR (Primary Loop Recirculation system) piping weld joints made of L-grade Type 316 stainless steel with 300 mm and 600 mm diameter were fabricated and residual stress analyses were performed in order to obtain stress distributions. Material properties (specific heat, thermal conductivity, Young’s modulus, stress-strain curve, etc.) were obtained and temperature history during welding and weld residual stress were measured using these mock-ups. Material properties were used in the heat transfer and stress analyses. Measured temperature history and residual stress were compared with the results of heat transfer and stress analyses, respectively. Residual stress analysis of the pipe weld joint is commonly performed using axisymmetric element. In some cases of the combination of pipe diameter and thickness, residual stress obtained by the conventional method might differ from the experimental result owing to the difference of heating and constraint conditions between the axisymmetric model and the actual condition. In order to obtain more precise results, heat transfer and stress analyses were performed, taking into account the adjustment of the boundary condition in the weld passes of the last layer and the constraint condition using a spring element, respectively. On the outer and inner surfaces, almost the same residual stress distributions were obtained for the FEM analysis and the measurement. The residual stress distributions for PLR piping with different diameters, thicknesses, welding processes and groove angles were obtained by FEM analysis. Based on the results of the analyses, the influences of these parameters on residual stress were evaluated.

Experimental verification of computational and sensitivity analysis on substrate deformation and plastic strain induced by hollow thin-walled WAAM structure

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Keval P. Prajadhiana ◽  
Yupiter H.P. Manurung ◽  
Alexander Bauer ◽  
Mohd Shahriman Adenan ◽  
Nur Izan Syahriah ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Sensitivity Analysis ◽  
Additive Manufacturing ◽  
Plastic Strain ◽  
Equivalent Plastic Strain ◽  
Transfer Coefficients ◽  
Content Type ◽  
Heat Transfer Coefficients ◽  
Adjusted Model ◽  
Wire Arc Additive Manufacturing

Purpose This paper aims to numerical and experimental analysis on substrate deformation and plastic strain induced by wire arc additive manufacturing. Design/methodology/approach The component has the form of a hollow, rectangular thin wall consisting of 25 deposition layers of SS316L on an SS304 substrate plate. Thermo-mechanical finite element analysis was applied with Goldak’s double-ellipsoidal heat-source model and a non-linear isotropic hardening rule based on von Mises’ yield criterion. The layer deposition was modelled using simplified geometry to minimize overall pre-processing work and computational time. Findings A new material modelling of SS316L was obtained from the chemical composition of the evolved component characterized by scanning electron microscope/energy dispersive X-ray and further generated by an advanced material-modelling software JMatPro. In defining heat-transfer coefficients, transient thermometric analysis was first performed in the bead and on the substrate, which was followed by an adjustment of the heat-transfer coefficients to reflect the actual temperature distribution. Based on the adjusted model and boundary conditions, sensitivity analysis was conducted prior to the ultimate simulation of substrate deformation and equivalent plastic strain. Furthermore, this simulation was verified by conducting a series of automated wire + arc additive manufacturing tests using robotic gas Metal arc welding with distortion measured by coordinate-measurement machine and equivalent plastic strain measured by optical three-dimensional-metrology measurements (Gesellschaft für Optische Messtechnik). Originality/value It can be concluded that a proper numerical computation using the adjusted model and property-evolved material exhibits a similar trend with acceptable agreement compared to the experiment by yielding an error percentage up to 30% for deformation and up to 21% for equivalent plastic strain at each individual measurement point.

scholarly journals Measurements of Heat Transfer Coefficients on Gas Turbine Components: Part I — Description, Analysis and Experimental Verification of a Technique for Use in Hostile Environments

1982 ◽  
Author(s):  
B. Barry ◽  
A. E. Forest ◽  
A. J. White
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Wall Temperature ◽  
Experimental Verification ◽  
Companion Paper ◽  
Transfer Coefficients ◽  
Flow Environment ◽  
Heat Transfer Coefficients ◽  
Internally Cooled ◽  
Hostile Environments

A method of determining local connective heat transfer coefficients around internally cooled components in a hostile flow environment is described. The method involves the measurement of the response of the wall temperature to perturbations in the coolant flow. A companion paper includes results obtained in cascades of turbine aerofoils using refined versions of the method.

Bulk Temperature Development in Transient Heat Transfer Measurements Using Heater Foils

2002 ◽  
Vol 124 (5) ◽  
pp. 982-985 ◽  
Author(s):  
Jens von Wolfersdorf
Keyword(s):  
Heat Transfer ◽  
Transient Heat Transfer ◽  
Simplified Model ◽  
Temperature History ◽  
Bulk Temperature ◽  
Transfer Coefficients ◽  
Transfer Experiment ◽  
Heat Transfer Coefficients ◽  
Temperature Development ◽  
Heat Transfer Parameter

The time and space development of the fluid bulk temperature in a transient heat transfer experiment for internal channel cooling investigations using heater foils is addressed. An analytical solution for uniform heat transfer coefficients is derived which shows the effect of wall heating on the bulk temperature during a transient test run. A simplified model is proposed for characterizing the bulk temperature development by introducing an upstream heat transfer parameter. With this, analytical solutions for the local wall temperature history can be derived. The presented solution can be used for data reduction of transient tests of this kind.

Temperature Variation History Prediction of Fully-Closed Adhesive Joint in Curing Process

2010 ◽  
Vol 44-47 ◽  
pp. 394-399
Author(s):  
Chu Chen ◽  
Zhi Guo Lu ◽  
Jian Ping Lin
Keyword(s):  
Heat Transfer ◽  
Heat Capacity ◽  
Adhesive Joint ◽  
Temperature History ◽  
Curing Process ◽  
Transfer Coefficients ◽  
Temperature Prediction ◽  
Heat Transfer Coefficients ◽  
Heat Transfer Theory ◽  
History Of

To describe the heat transfer of fully-closed adhesive joint in curing process, adhesive joint, enclosure for closing joints and its inner air are simplified as a multi-lumped-heat-capacity system neglecting the heat from adhesive chemical reaction. Based on heat transfer theory, a temperature prediction model of fully-closed joint was proposed. Combining experimental temperature history of the joint with finite difference method, the combined heat transfer coefficients of adhesive under different curing temperatures were obtained according to Newton's heat transfer formula. And the model was validated by the experiments. The results revealed that the model can be used to predict the temperature of fully-closed adhesive joint in curing process.

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