Modeling of Spray Deposition and Robot Motion Optimization for a Gas Turbine Application

2000 ◽  
Author(s):  
A. Hansbo ◽  
P.E. Nylén
Keyword(s):  
Coating Thickness ◽  
Spray Deposition ◽  
Engineering Practice ◽  
Programming System ◽  
Trial And Error ◽  
Invariant Surfaces ◽  
Motion Optimization ◽  
Matlab Implementation ◽  
Plasma Sprayed ◽  
Rotationally Invariant

Abstract The complexity of many components being coated in the aircraft industry today makes the traditional trial and error approach to obtain uniform coatings inadequate. To reduce programming time and further increase process accuracy a more systematic approach to develop robot trajectories is needed. In earlier work, a mathematical model was developed to predict coating thickness for thermal spray deposition on rotating objects with rotationally invariant surfaces. The model allows for varying spray distance and spray direction but is simple enough to give very short simulation times. An iterative method for robot feed optimization to obtain uniform coatings was also proposed. Currently, the use of the model in engineering practice is being evaluated. A MATLAB implementation of the model has been integrated with a commercial off-line programming system, giving a powerful and efficient tool to predict and optimize coating thickness. Simulations and experimental verifications are presented for two zirconia plasma sprayed parts.

Modelling of Coating Thickness, Heat Transfer and Fluid Flow and It's Correlation with the TBC Microstructure for a Plasma Sprayed Gas Turbine Application

1998 ◽  
Author(s):  
P. Nylen ◽  
J. Wigren ◽  
L. Pejryd ◽  
M.-O. Hansson
Keyword(s):  
Heat Transfer ◽  
Fluid Flow ◽  
Gas Turbine ◽  
Coating Thickness ◽  
Spray Deposition ◽  
Temperature History ◽  
Particle Model ◽  
Barrier Coating ◽  
Discrete Particle Model ◽  
Turbine Component

Abstract The plasma spray deposition of a zirconia thermal barrier coating (TBC) on a gas turbine component has been examined using analytical and experimental techniques. The coating thickness was simulated by the use of commercial off-line programming software. The impinging jet was modelled by means of a finite difference elliptic code using a simplified turbulence model. Powder particle velocity, temperature history and trajectory were calculated using a stochastic discrete particle model. The heat transfer and fluid flow model were then used to calculate transient coating and substrate temperatures using the finite element method. The predicted thickness, temperature and velocity of the particles and the coating temperatures were compared with these measurements and good correlations were obtained. The coating microstructure was evaluated by optical and scanning microscopy techniques. Special attention was paid to the crack structures within the top coating. Finally, the correlation between the modelled parameters and the deposit microstructure was studied.

Modeling of Oxidation of Plasma-Sprayed Molybdenum Coatings

2000 ◽  
Author(s):  
Y.P. Wan ◽  
X.Y. Jiang ◽  
H. Zhang ◽  
S. Sampath ◽  
V. Prasad ◽  
...  
Keyword(s):  
Spray Deposition ◽  
Mechanical Energy ◽  
Particle Surface ◽  
Conservation Equation ◽  
Type Model ◽  
Energy Conservation Equation ◽  
Thin Oxide Film ◽  
Molten Particle ◽  
Plasma Sprayed ◽  
Substrate Temperatures

Abstract A model for oxidation of molybdenum particles during plasma spray deposition is developed. The diffusion of metal an-ions or oxygen cat-ions through a thin oxidized film, chemical reactions on the surface, and diffusion of oxidant in gas phase are considered as possible rate-controlling mechanisms with controlling parameters as the temperature of the particle surface, and local oxygen concentration and flow field surrounding the particle. The deposition of molten particle and its rapid solidification and deformation is treated using a Madejski-type model, in which the mechanical energy conservation equation is solved to determine the splat deformation and one-dimensional heat conduction equation with phase change is solved to predict the solidification and temperature evolution. Calculations are performed for a single molybdenum particle sprayed under the Sulzer Metco-9MB spraying conditions. Results show that the mechanism that controls the oxidation of this droplet is the diffusion of metal/oxygen ions through a very thin oxide film. A higher substrate temperature results in a larger rate of oxidation at the splat surface, and hence, a larger oxygen content in the coating layer. Compared to the oxidation of droplet during m-flight, the oxidation during deposition is not weak and can become dominant at high substrate temperatures.

Enhanced Osteoblast Adhesion on a Novel Hydroxyapatite Coating

2003 ◽  
Vol 774 ◽  
Author(s):  
Michiko Sato ◽  
Elliott B. Slamovich ◽  
Thomas J. Webster
Keyword(s):  
Glycolic Acid ◽  
Spray Deposition ◽  
Sol Gel ◽  
Titanium Implant ◽  
Coating Material ◽  
Ha Coating ◽  
Implant Coating ◽  
Osteoblast Adhesion ◽  
Plasma Sprayed ◽  
Gel Processing

AbstractPlasma spray deposition of hydroxyapatite (HA) onto a titanium implant involves high temperatures that may alter HA crystallinity and induce cracks in the coating. For this reason, the objective of this study was to design a novel HA coating material and method. Titanium was coated with HA, titania, and Poly (dl-lactic-glycolic acid) (PLGA) using sol-gel processing. The biocompatibility of the HA coating in the present study was compared to that of a plasmasprayed HA coating. Results of this study showed that osteoblast adhesion was promoted more in the HA coating proposed in this study than on the plasma-sprayed HA coating. In addition, hydrothermal treatment of the coating appeared to improve the biocompatibility of the HA coating. Since osteoblast adhesion is a necessary requirement for increased bonding of an implant to juxtaposed bone, these results support that hydrothermally sol-gel processed HA may be an optimal implant coating material and method.

Thermal Analysis of Ceramic Coated Aluminium Piston with Slots

2014 ◽  
Vol 592-594 ◽  
pp. 786-790
Author(s):  
M.R. Chitthaarth ◽  
K. Manivannan
Keyword(s):  
Thermal Analysis ◽  
Thermal Expansion ◽  
Coating Thickness ◽  
Ceramic Coating ◽  
Working Condition ◽  
Middle Layer ◽  
Piston Crown ◽  
Alsi Alloy ◽  
Aluminium Piston ◽  
Plasma Sprayed

The main aim is to control thermal expansion in aluminium piston at high working condition. A plasma sprayed ceramic coating (TBC) is applied on the piston crown as a top coat and NiCrAl is applied as the middle layer as bond coat to improve the addition strength between the top coat and the metal subtract layer as AlSi alloy; we introduce a thermal slot on the piston shrink to regulate the heat flow in piston and make it cooler. We analyse the piston with these two implementations to determine the thermal analysis of the piston. The results can be shown in the various comparisons of coating thickness of top coat with thermal slots on the piston shrink. Increase in coating thickness reduces the stress in the coatings. It is observed that 85°C increase in 0.8mm coat than the ordinary piston.

scholarly journals Prediction Model of Coating Growth Rate for Varied Dip-Angle Spraying Based on Gaussian Sum Model

2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Yong Zeng ◽  
Yakun Zhang ◽  
Junxue He ◽  
Hai Zhou ◽  
Chunwei Zhang ◽  
...  
Keyword(s):  
Growth Rate ◽  
Theoretical Model ◽  
Prediction Model ◽  
Coating Thickness ◽  
Least Square ◽  
Programming System ◽  
Gaussian Sum ◽  
Sample Points ◽  
Dip Angle ◽  
Coating Growth

In automatic spraying of spray painting robot, in order to solve the problems of coating growth rate modeling for varied dip-angle spraying technology, a prediction mode of coating growth rate using the Gaussian sum model is proposed. Based on the Gaussian sum model, a theoretical model for coating growth rate with varied dip-angle spraying is established by using the theory of differential geometry. The coating thickness of the sample points in the distribution range of the coating was obtained by making the experiment of varied dip-angle spraying. Based on the theoretical model, the nonlinear least square method is used to fit the coating thickness of the sample points and the parameter values of the theoretical model are calculated. By analyzing the variation law of the parameters with the spray dip-angle, the prediction model of coating growth rate for varied dip-angle spraying is established. Experiments have shown that the prediction model has good fitting precision; it can satisfy the real-time requirement with varied dip-angle spraying trajectory planning in the offline programming system.

What Engineering Designers Leave Behind: Developing a Cognitive Coding Scheme for Student Design Journals

2010 ◽  
Author(s):  
Sophoria Westmoreland ◽  
Linda C. Schmidt
Keyword(s):  
Design Process ◽  
Cognitive Processes ◽  
Limited Resources ◽  
Engineering Practice ◽  
Trial And Error ◽  
Coding Scheme ◽  
Innovative Solutions ◽  
Design Documentation ◽  
Problem Solving Strategies ◽  
Real World Problems

Some historically successful engineering inventions have been designed by trial and error as was the famous case of Thomas Edison’s light bulb. No contemporary design researcher would advocate a tedious, trial-and-error methodology as the basis for engineering practice. The 21st century engineer is expected to create innovative solutions to real world problems with limited resources and limited time. Successful engineering design methods are those that substitute trial-and-error with practice-based guidance (e.g., TRIZ), mathematical analysis (e.g., optimization), general problem-solving strategies (e.g., functional decomposition and synthesis), or good cognitive thinking strategies (e.g., Synectics). This research is placed in the last category, studying the cognitive processes that can be observed in recorded work of engineering designers. This study is the first step in research intended to go further into the designers mind and reveal new insights about the design process. This paper presents a cognitive coding scheme model to organize and categorize designer “thinking” as recorded in design documentation. The product of this research can be used to instruct curriculum on teaching the design process for students and professional engineers.

scholarly journals Mechanical Behavior Study of Plasma Sprayed Hydroxyapatite Coatings onto Ti6Al4V Substrates Using Scratch Test

2010 ◽  
Vol 638-642 ◽  
pp. 641-646
Author(s):  
Aliasghar Behnamghader ◽  
Denis Najjar ◽  
Alain Iost ◽  
Stephane Benayoun
Keyword(s):  
Mechanical Behavior ◽  
Coating Thickness ◽  
Roughness Parameter ◽  
Fracture Mechanisms ◽  
Mechanical Resistance ◽  
Substrate Roughness ◽  
Average Roughness ◽  
Arithmetic Average ◽  
Hydroxyapatite Coatings ◽  
Plasma Sprayed

Mechanical behavior and fracture mechanisms of plasma sprayed hydroxyapatite coatings on Ti-6Al-4V substrate were assessed taking into consideration two variables: the coating thickness and the substrate roughness. The results show that the specimens having a substrate arithmetic average roughness parameter Ra = 2.29 µm is favorable with respect to Ra = 1.23 µm. For coating thickness above 105 µm, cracks can be observed in the coating/substrate interface and the higher critical load Pc2 (used generally in comparative evaluation of adherence) decreases. A 90 µm coating thickness sprayed on a substrate having an arithmetic average roughness parameter Ra equal to 2.29 µm seems to be the best compromise between microstructure, mechanical resistance (high critical loads and fairly good contact quality) and long term stability in the physiological medium (low dissolution rate) for an orthopedic application.

Loads Borne on Elastic Supports

1944 ◽  
Vol 151 (1) ◽  
pp. 265-273
Author(s):  
E. H. Lamb
Keyword(s):  
Motor Vehicles ◽  
Rolling Stock ◽  
Engineering Practice ◽  
Trial And Error ◽  
Large Measure ◽  
Short Account ◽  
Elastic Supports ◽  
Wheel Loading ◽  
Made In ◽  
Railway Rolling Stock

There are many instances in engineering practice of loads carried upon a number of supports which possess some degree of elasticity and where, owing to the number of the supports, the proportion of the load carried by each cannot be determined by the principles of statics alone but depends in a large measure on the elastic properties of the supports. Problems of this indeterminate type are of common occurrence in the theory of structures and the present paper describes an exact method specially suitable for application to such problems as occur in connexion with the wheel loading of railway rolling stock and locomotives, motor vehicles, etc., and in particular is directed to the question of the adjustment of the springs necessary to produce a desired distribution of the loads upon them. It is shown in this latter case that if the initial loading on the springs, i.e. before adjustment is known by direct measurement, the equations which give the amounts of the adjustments to be made in terms of the desired increments of load take a conveniently simple form, and the adjustments can be calculated and made once for all without any necessity for trial and error methods. A few simple examples are worked out in the paper and an Appendix contains a short account of an extension of Castigliano's second theorem from which the equations in the paper may be derived, and an example showing the application of the method to the adjustment of the wheel loading of a locomotive.

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