Numerical investigation of temperature field of different mechanisms in laser forming

2011 ◽  
Vol 226 (8) ◽  
pp. 2118-2125 ◽  
Author(s):  
Yongjun Shi ◽  
Peng Yi ◽  
Yancong Liu
Keyword(s):  
Temperature Field ◽  
Temperature Distribution ◽  
Process Parameters ◽  
Material Properties ◽  
Industrial Applications ◽  
Laser Forming ◽  
Temperature Zone ◽  
Numerical Investigations ◽  
Distribution Features ◽  
Plate Size

In laser forming, deformation of a plate is different when different mechanisms play dominant roles. A deformation field depends on a temperature field that is related to process parameters, material properties and plate size. Numerical investigations of temperature distribution with different process parameters were carried out when different mechanisms were active. A critical temperature for generating plastic deformation was investigated. Four temperature feature parameters were defined based on the temperature distribution characteristics of the high-temperature zone. The numerical results show that the temperature gradient is obviously different under different mechanism conditions. The temperature distribution features for the different mechanisms have a larger difference, which is helpful for the discrimination of different mechanisms according to the temperature field in real industrial applications.

Study on overlapping of two sequential scans in laser forming

2007 ◽  
Vol 221 (9) ◽  
pp. 993-997 ◽  
Author(s):  
H Shen ◽  
J Zhou ◽  
Z Q Yao
Keyword(s):  
Plastic Strain ◽  
Material Properties ◽  
Structural Model ◽  
Three Dimensional ◽  
High Strength ◽  
Laser Beams ◽  
Laser Forming ◽  
Numerical Investigations ◽  
Localized Heating ◽  
The Difference

Laser forming can utilize localized heating for the forming of high strength alloys and use combinations of straightandcurved lines to produce three-dimensional formedcomponents, which are of significant value to industries of aerospace, shipbuilding, and microelectronics. A three-dimensional non-linear, indirectly coupled thermal—structural model for the overlapping ratio of two sequential laser beams scanning is established, accounting for temperature dependency of material properties. Numerical results are verified by experimental data. Numerical investigations are carried out to examine the difference in plastic strain distributions under different overlapping ratios. The results show that the bending angle is larger when the size of plastic zone on the top surface is wider, although the plastic strain is smaller.

Experimental investigation of the curing behaviour of fibre composite structures with snap-cure polymer systems

2018 ◽  
Vol 9 (6) ◽  
pp. 768-778
Author(s):  
Rafal Stanik ◽  
Albert Langkamp ◽  
Michael Müller ◽  
Maik Gude ◽  
Anna Boczkowska
Keyword(s):  
Experimental Investigation ◽  
Temperature Field ◽  
Process Parameters ◽  
Material Properties ◽  
Manufacturing Process ◽  
Composite Structures ◽  
Fibre Composite ◽  
Uniform Design ◽  
Curing Process ◽  
Content Type

PurposeNovel snap-cure polymers (SCPs), as matrix systems for high-performance fibre composite materials, provide high potential for manufacturing of component families with small batch sizes and high variability. Especially, the processing of powdered SCP is associated with relatively simple and inexpensive tools. In addition, because of their curing behaviour, they allow short tooling times so that the production of small batch size components is possible in relatively short cycle times. To enable an efficient manufacturing process, an understanding of the curing process is necessary. An adjustment of the process parameters for a uniform design of the temperature field in the material during the manufacturing process is essential. The paper aims to discuss this issue.Design/methodology/approachFor this, a powder SCP resin system was investigated under process-specific conditions. An experimental test approach for determination of various thermal and kinetic material properties was developed. For the adjustment of the process parameters and monitoring of the curing state during the manufacturing process, a kinetic material model was determined. In the end, the validation of the determined model was performed. For this, the temperature distribution under process- specific conditions was measured in order to monitor the curing state of the material.FindingsThe experimental investigation showed an uneven temperature field in the material, which leads to an inhomogeneous curing process. This can lead to residual stresses in the structure, which have a critical impact on the material properties.Originality/valueThe determined kinetic model allows a prediction of the curing reaction and adjustment of the process parameters which is essential, especially for thick-walled components with SCPs.

scholarly journals Fire Model Test on Temperature Field in the Rescue Station of an Extralong Railway Tunnel

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Yanhua Zeng ◽  
Kelin Liu ◽  
Yong Fang ◽  
Xianfu Zhang ◽  
Yun Bai
Keyword(s):  
Temperature Field ◽  
Temperature Distribution ◽  
Model Test ◽  
Source Position ◽  
Temperature Zone ◽  
Railway Tunnel ◽  
Fire Model ◽  
Fire Source ◽  
Ventilation Condition ◽  
Chimney Effect

A rescue station is necessary for an extralong railway tunnel, whose length is generally greater than 20 km. In the rescue station, passenger evacuation, fire fighting, and protection of passengers are organized. It is important to discover the temperature distribution in a rescue station where a train is on fire. This paper performs a similarity simulation model test at 1 : 10 geometric scale to investigate the temperature field in a rescue station. A gasoline pool fire was used as the fire source. The influences of the fire source position and ventilation condition on the temperature field were studied. The results show that (a) the temperature distribution along the tunnel is stable without ventilation, the temperature is lowest when the fire occurs 50 m from the entrance; (b) the fresh air stirred up by fans promotes burning and increases the temperature; (c) the chimney effect causes the temperature field to skew in an uphill direction; (d) the opening of both fans in the adit makes the high-temperature zone to connect through; and (e) the temperature increase at the rescue station can be divided into four stages, and the response of different fire source positions to the opening of fans is not consistent. These findings provide a basis for personnel escape design and a foundation for further study of temperature distribution in a tunnel with a rescue station.

Numerical Simulation of Solidification Process for a Machine Tool Bed

2011 ◽  
Vol 675-677 ◽  
pp. 987-990
Author(s):  
Ling Tang ◽  
Xu Dong Wang ◽  
Hai Jing Zhao ◽  
Man Yao
Keyword(s):  
Heat Transfer ◽  
Temperature Field ◽  
Temperature Distribution ◽  
Machine Tool ◽  
Computation Time ◽  
Solidification Process ◽  
Field Calculation ◽  
Original Design ◽  
Calculation Results ◽  
Improved Design

In this paper, the flow, heat transfer and stress during solidification process of the machine tool bed weighed about 2.5ton that has been optimized by structural topologymethod, was calculated with ProCAST software, and the causes of the crack forming in the casting of the machine tool bed was analysed. According to the calculation results, the structural design of the local part where cracks tends to form has been improved, and the heat transfer and the stress are calculated again. By comparing the temperature field with filling of molten cast iron and without filling, it has been found that there was little effect of filling on the results of temperature distribution of the cast, therefore the effect of filling can be ignored in the following temperature field calculation to save computation time. The model has been simplified in the stress field calculation with considering the complexity of the machine tool bed and the cost of computation. Then, the merits and demerits of the original design and the improved design are compared and analyzed depending on the calculated temperature and stress results. It is suggested that the improved one could get a more uniform temperature distribution and then the trend of the crack occurring can be greatly reduced. These results could provide a guide for the actual casting production, achieving the scientific control of the production of castings, ensuring the quality of the castings.

scholarly journals Taguchi optimization and scale up of xylanase from Bacillus licheniformis isolated from hot water geyser

2020 ◽  
Vol 18 (1) ◽  
Author(s):  
Girisha Malhotra ◽  
Shilpa S. Chapadgaonkar
Keyword(s):  
Process Parameters ◽  
Wheat Bran ◽  
Scale Up ◽  
Industrial Applications ◽  
Hot Water ◽  
Optimization Strategy ◽  
Taguchi Optimization ◽  
Xylanase Production ◽  
Alkali Tolerance ◽  
Optimized Conditions

Abstract Background Xylanase is one of the widely applied industrial enzymes with diverse applications. Thermostability and alkali tolerance are the two most desirable qualities for industrial applications of xylanase. In this paper, we reveal the statistical Taguchi optimization strategy for maximization of xylanase production. The important process parameters pH, temperature, concentration of wheat bran, and concentration of yeast extract were optimized using the Taguchi L8 orthogonal array where the 4 factors were considered at 2 levels (high and low). Results The optimized conditions given by model were obtained as follows: (i) pH 6, (ii) culture temperature 35 °C, (iii) concentration of xylan 2% w/v, (iv) concentration of wheat bran 2.5% w/v. The production was scaled upto 2.5 L bioreactor using optimized process parameters. A high xylanase titer of 400 U/ml could be achieved in less than 60 h of culture in the reactor. Conclusion Optimization was successful in achieving about threefold increase in the yield of xylanase. The optimized conditions resulted in a successful scale up and enhancement of xylanase production.

scholarly journals Influence of High-Productivity Process Parameters on the Surface Quality and Residual Stress State of AISI 316L Components Produced by Directed Energy Deposition

2021 ◽  
Author(s):  
Gabriele Piscopo ◽  
Alessandro Salmi ◽  
Eleonora Atzeni
Keyword(s):  
Surface Roughness ◽  
Residual Stresses ◽  
Surface Quality ◽  
Process Parameters ◽  
Energy Deposition ◽  
Industrial Applications ◽  
High Productivity ◽  
Directed Energy Deposition ◽  
Productivity Process ◽  
Directed Energy

AbstractThe production of large components is one of the most powerful applications of laser powder-directed energy deposition (LP-DED) processes. High productivity could be achieved, when focusing on industrial applications, by selecting the proper process parameters. However, it is of crucial importance to understand the strategies that are necessary to increase productivity while maintaining the overall part quality and minimizing the need for post-processing. In this paper, an analysis of the dimensional deviations, surface roughness and subsurface residual stresses of samples produced by LP-DED is described as a function of the applied energy input. The aim of this work is to analyze the effects of high-productivity process parameters on the surface quality and the mechanical characteristics of the samples. The obtained results show that the analyzed process parameters affect the dimensional deviations and the residual stresses, but have a very little influence on surface roughness, which is instead dominated by the presence of unmelted particles.

scholarly journals A FEM-Based 2D Model for Simulation and Qualitative Assessment of Shot-Peening Processes

Materials ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 2784
Author(s):  
Georgios Maliaris ◽  
Christos Gakias ◽  
Michail Malikoutsakis ◽  
Georgios Savaidis
Keyword(s):  
Process Parameters ◽  
Material Properties ◽  
Shot Peening ◽  
Qualitative Assessment ◽  
Experimental Investigations ◽  
Elastoplastic Material ◽  
Size Distributions ◽  
User Friendly ◽  
The Impact ◽  
2D Model

Shot peening is one of the most favored surface treatment processes mostly applied on large-scale engineering components to enhance their fatigue performance. Due to the stochastic nature and the mutual interactions of process parameters and the partially contradictory effects caused on the component’s surface (increase in residual stress, work-hardening, and increase in roughness), there is demand for capable and user-friendly simulation models to support the responsible engineers in developing optimal shot-peening processes. The present paper contains a user-friendly Finite Element Method-based 2D model covering all major process parameters. Its novelty and scientific breakthrough lie in its capability to consider various size distributions and elastoplastic material properties of the shots. Therewith, the model is capable to provide insight into the influence of every individual process parameter and their interactions. Despite certain restrictions arising from its 2D nature, the model can be accurately applied for qualitative or comparative studies and processes’ assessments to select the most promising one(s) for the further experimental investigations. The model is applied to a high-strength steel grade used for automotive leaf springs considering real shot size distributions. The results reveal that the increase in shot velocity and the impact angle increase the extent of the residual stresses but also the surface roughness. The usage of elastoplastic material properties for the shots has been proved crucial to obtain physically reasonable results regarding the component’s behavior.

scholarly journals Study on the Influence of Surface Temperature Field of Aluminum Alloy Etched by Laser Water Jet Composite Machining

Materials ◽  
2020 ◽  
Vol 13 (14) ◽  
pp. 3206
Author(s):  
Xuehui Chen ◽  
Xin Xu ◽  
Wei Liu ◽  
Lei Huang ◽  
Hao Li ◽  
...  
Keyword(s):  
Aluminum Alloy ◽  
Temperature Field ◽  
Surface Temperature ◽  
Process Parameters ◽  
Water Jet ◽  
Laser Machining ◽  
Material Surface ◽  
Laser Etching ◽  
Surface Temperature Field

This paper studies the compound effect of liquid medium and laser on the workpiece and analyses the law of material surface temperature change during the processing. Taking 7075-T6 aluminum alloy as the research object, the surface temperature field of aluminum alloy processed using water-jet-assisted laser machining under different process parameters was simulated using finite element software. In addition, the temperature field of the material surface was detected in real-time using the self-built water-jet-assisted laser machining temperature field detection system, and the processing results were observed and verified using an optical microscope, scanning electron microscope, and energy spectrum analyzer. The results show that when the water jet inflow angle is 45°, the heat-affected area of the material surface is the smallest, and the cooling effect of the temperature field of the material surface is better. Considering the liquidus melting point of 7075 aluminum alloys, it is concluded that the processing effect is better when the water jet velocity is 14 m·s−1, the laser power is 100 W, and the laser scanning speed is 1.2 mm·s−1. At this time, the quality of the tank is relatively good, there are no cracks in the bottom of the tank, and there is less slag accumulation. Compared with anhydrous laser etching, water-jet-assisted laser etching can reduce the problems of micro-cracks, molten slag, and the formation of a recast layer in laser etching and improve the quality of the workpiece, and the composition of the bottom slag does not change. This study provides theoretical guidance and application support for the selection and optimization of process parameters for water-jet-assisted laser etching of aluminum alloy and further enriches the heat transfer mechanism of multi-field coupling in the process of water-jet-assisted laser machining.

An analytical solution of a two-dimensional temperature field in a hollow cylinder under a time periodic boundary condition using Fourier series

2009 ◽  
Vol 223 (8) ◽  
pp. 1889-1901 ◽  
Author(s):  
G Atefi ◽  
M A Abdous ◽  
A Ganjehkaviri ◽  
N Moalemi
Keyword(s):  
Boundary Condition ◽  
Temperature Field ◽  
Fourier Series ◽  
Temperature Distribution ◽  
Analytical Solution ◽  
Hollow Cylinder ◽  
Periodic Boundary Condition ◽  
Periodic Boundary ◽  
Separation Of Variables ◽  
Two Dimensional

The objective of this article is to derive an analytical solution for a two-dimensional temperature field in a hollow cylinder, which is subjected to a periodic boundary condition at the outer surface, while the inner surface is insulated. The material is assumed to be homogeneous and isotropic with time-independent thermal properties. Because of the time-dependent term in the boundary condition, Duhamel's theorem is used to solve the problem for a periodic boundary condition. The periodic boundary condition is decomposed using the Fourier series. This condition is simulated with harmonic oscillation; however, there are some differences with the real situation. To solve this problem, first of all the boundary condition is assumed to be steady. By applying the method of separation of variables, the temperature distribution in a hollow cylinder can be obtained. Then, the boundary condition is assumed to be transient. In both these cases, the solutions are separately calculated. By using Duhamel's theorem, the temperature distribution field in a hollow cylinder is obtained. The final result is plotted with respect to the Biot and Fourier numbers. There is good agreement between the results of the proposed method and those reported by others for this geometry under a simple harmonic boundary condition.

Simulation of Concrete in Winter with Self-Limiting Heating Band

2022 ◽  
Vol 905 ◽  
pp. 297-302
Author(s):  
Lin Liu ◽  
Mei Qing Zhang
Keyword(s):  
Temperature Field ◽  
Temperature Distribution ◽  
Analytical Calculation ◽  
Heating Zone ◽  
Surface Layout ◽  
Combined Action ◽  
Early Age Concrete ◽  
Cracking Risk ◽  
Concrete Component ◽  
Better Than

In order to investigate the temperature distribution and cracking risk of concrete in winter under the combined action of heating zone and air layer, the analytical calculation method of early age concrete temperature field of concrete component under the combined action of self-limiting temperature band, cement hydration and air layer was established by taking concrete prism with self-limiting temperature band as an example. The model is applied to calculate and analyze the temperature distribution of concrete under different boundary conditions and different additional thermal field modes. The results show that: Under the conditions of internal layout, surface layout and thermal insulation layer outside the formwork, all components reach the critical strength after heating and curing for three days, which indicates that the heating band can provide temperature conditions for concrete curing in winter. Comparing the temperature field of different layout positions of heating belt, the uniformity of temperature field of heating belt outside the formwork is better than the other two layout methods.

Sign in / Sign up

Export Citation Format

Share Document