An experimental and numerical study of the expansion forming of a thick-walled microgroove tube

2008 ◽  
Vol 223 (3) ◽  
pp. 689-697 ◽  
Author(s):  
D Tang ◽  
Y Peng ◽  
D Li
Keyword(s):  
Mechanical Performance ◽  
Numerical Study ◽  
Surface Profile ◽  
Processing Parameters ◽  
Forming Process ◽  
Axial Section ◽  
Die Geometry ◽  
Contact Points ◽  
Industrial Sectors ◽  
Full Contact

CO2 refrigerant-based air conditioning and refrigeration (ACR) is an increasing concern in many industrial sectors for its zero ozone depletion potential. One of the major requirements in its application is the forming technology of thick-walled tube according to the extremely high pressure working conditions of the ACR system. This article presents a study on the expansion process joining the thick-walled microgroove copper tube to aluminium fins. Experiments of the forming process have been carried out. Finite-element models are developed to investigate the deformation of overall and local structures. Evaluation of the joining quality along the longitude axis of the tube is first attempted. The agreement of the results on the contact surface profile confirms that the joint is far away from full contact in the axial section. Formation mechanism of the unexpected contact status lies in displacement of the contact points along the section of the fin collar, which is mainly related to the expanding ratio. To improve the forming quality, discussion on processing parameters and die geometry is conducted. Results show that the expanding ratio is the major factor influencing the thermal—mechanical performance of the joint and 2–6 per cent can be the comprehensively beneficial range for a thick-walled ACR tube; average contact pressure can reach 1.76 Mpa under proper set. The results are helpful for improving the energy efficiency ratio performance of the natural refrigerant-based system.

Numerical Study on Forming Process by Continuous Resistance Heating

2010 ◽  
Vol 154-155 ◽  
pp. 867-872
Author(s):  
Zheng Xing Men ◽  
Jie Zhou ◽  
Meng Han Wang ◽  
Chang Wei Shao
Keyword(s):  
Temperature Distribution ◽  
Contact Resistance ◽  
Numerical Study ◽  
Mechanical Analysis ◽  
Transient Temperature ◽  
Resistance Heating ◽  
Forming Force ◽  
Forming Process ◽  
Billet Temperature ◽  
Die Geometry

In the present study, an axis-symmetric electro-thermo-mechanical model has been developed to analyze a deformation process by continuous resistance heating. To obtain the transient temperature field prior to forming, a novel temperature-dependent model of the contact resistance was developed in the thermal-electrical analysis. The influences of the contact resistance, the current intensity and the die geometry on the temperature distribution were investigated. In the subsequent electro-thermo-mechanical analysis of the forming process by continuous resistance heating, the variations of the billet temperature distribution, forming force were obtained. The simulation results correspond well with experimental measured values. Furthermore, the influence of a current increasing during forming on the billet temperature and forming force was predicted in order to optimize the forming technology by continuous resistance heating.

Prediction of Plastic Wrinkling Using the Energy Method

1999 ◽  
Vol 66 (3) ◽  
pp. 646-652 ◽  
Author(s):  
J. Cao
Keyword(s):  
Metal Forming ◽  
Side Wall ◽  
Processing Parameters ◽  
Analytical Models ◽  
Forming Process ◽  
Efficient Tool ◽  
Die Geometry ◽  
Prediction And Prevention ◽  
Flange Wrinkling ◽  
Metal Forming Process

The prediction and prevention of wrinkling during a sheet metal forming process have been challenging issues on the design of part shape, die geometry, and processing parameters. In an effort to provide a reliable and efficient tool to assess the onset of wrinkling, analytical models for flange wrinkling and straight side-wall wrinkling are presented here. Using a combination of energy conservation and plastic bending theory, the critical buckling wavelength and stress are calculated as functions of the boundary conditions (displacement constraint and binder pressure). Comparisons between the numerical and experimental results are given for both cases and excellent agreement is obtained.

Numerical Study of Thickness Distribution of Stretch-Blow Bottles for Defects Prediction

2009 ◽  
Vol 413-414 ◽  
pp. 691-698 ◽  
Author(s):  
Ya Yue Pan ◽  
Shui Ying Zheng ◽  
Xiao Hong Pan
Keyword(s):  
Numerical Study ◽  
Thickness Distribution ◽  
Processing Parameters ◽  
Technological Parameters ◽  
Forming Process ◽  
Molding Process ◽  
Pet Bottles ◽  
Blow Molding ◽  
Stretch Blow Molding ◽  
Good Agreement

Nowadays, polyethylene terephthalate (PET) bottles have been increasingly used as drink containers. They are usually manufactured by a stretch-blow molding process. The improper parameters set in the stretch blow molding process may lead to many defects in the stretch-blow bottle. Finite Element (FE) simulations of the forming process were performed in this paper. The influences of the technological parameters, such as the balance between stretching and blowing rate, the movement of the stretch rod and the inflation pressure, were studied. As a result, the defects, such as over-thin area, cracking and deformation, can be predicted by this method. Especially, it is shown that the cracking in the bottom of products may result from the improper values of the dwell time and the stretch rate. The trends shown by the simulation results are in good agreement with the experimental results. The method can be applied to predict the probable defects, assess the structural properties, and optimize the processing parameters of the stretch blow molding process.

NUMERICAL STUDY ON THE MECHANICAL PERFORMANCE OF GRAPHENE BRIDGES ON SILLICON THIN FILM TRANSISTORS

2011 ◽  
Author(s):  
Byung-Jae Kim ◽  
Hyeon-Seok Seo ◽  
Won-Ho Lee ◽  
Jong-Hyun Ahn ◽  
Youn-Jea Kim
Keyword(s):  
Thin Film ◽  
Thin Film Transistors ◽  
Mechanical Performance ◽  
Numerical Study

scholarly journals Long-fibre reinforced polymer composites by 3D printing: influence of nature of reinforcement and processing parameters on mechanical performance

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Francis Dantas ◽  
Kevin Couling ◽  
Gregory J. Gibbons
Keyword(s):  
Carbon Fibre ◽  
Polymer Composites ◽  
Mechanical Performance ◽  
Flexural Modulus ◽  
Matrix Material ◽  
Processing Parameters ◽  
Fibre Reinforcement ◽  
Reinforced Polymer ◽  
Unreinforced Material ◽  
Fibre Reinforced Polymer

Abstract The aim of this study was to identify the effect of material type (matrix and reinforcement) and process parameters, on the mechanical properties of 3D Printed long-fibre reinforced polymer composites manufactured using a commercial 3D Printer (Mark Two). The effect of matrix material (Onyx or polyamide), reinforcement type (Carbon, Kevlar®, and HSHT glass), volume of reinforcement, and reinforcement lay-up orientation on both Ultimate Tensile Strength (UTS) and Flexural Modulus were investigated. For Onyx, carbon fibre reinforcement offered the largest increase in both UTS and Flexural Modulus over unreinforced material (1228 ± 19% and 1114 ± 6% respectively). Kevlar® and HSHT also provided improvements but these were less significant. Similarly, for Nylon, the UTS and Flexural Modulus were increased by 1431 ± 56% and 1924 ± 5% by the addition of carbon fibre reinforcement. Statistical analysis indicated that changing the number of layers of reinforcement had the largest impact on both UTS and Flexural Strength, and all parameters were statistically significant.

scholarly journals Fused Deposition Modelling of Fibre Reinforced Polymer Composites: A Parametric Review

2021 ◽  
Vol 5 (1) ◽  
pp. 29
Author(s):  
Narongkorn Krajangsawasdi ◽  
Lourens G. Blok ◽  
Ian Hamerton ◽  
Marco L. Longana ◽  
Benjamin K. S. Woods ◽  
...  
Keyword(s):  
Process Parameters ◽  
Mechanical Performance ◽  
Fibre Length ◽  
Processing Parameters ◽  
Thermoplastic Composite ◽  
Fused Deposition Modelling ◽  
Layer By Layer ◽  
Fused Deposition ◽  
Fibre Reinforced Polymer ◽  
Printing Parameters

Fused deposition modelling (FDM) is a widely used additive layer manufacturing process that deposits thermoplastic material layer-by-layer to produce complex geometries within a short time. Increasingly, fibres are being used to reinforce thermoplastic filaments to improve mechanical performance. This paper reviews the available literature on fibre reinforced FDM to investigate how the mechanical, physical, and thermal properties of 3D-printed fibre reinforced thermoplastic composite materials are affected by printing parameters (e.g., printing speed, temperature, building principle, etc.) and constitutive materials properties, i.e., polymeric matrices, reinforcements, and additional materials. In particular, the reinforcement fibres are categorized in this review considering the different available types (e.g., carbon, glass, aramid, and natural), and obtainable architectures divided accordingly to the fibre length (nano, short, and continuous). The review attempts to distil the optimum processing parameters that could be deduced from across different studies by presenting graphically the relationship between process parameters and properties. This publication benefits the material developer who is investigating the process parameters to optimize the printing parameters of novel materials or looking for a good constituent combination to produce composite FDM filaments, thus helping to reduce material wastage and experimental time.

Numerical Study of the Flow Forming Process of AISI 630 Stainless Steel

2011 ◽  
Vol 264-265 ◽  
pp. 24-29 ◽  
Author(s):  
Seyed Mohammad Ebrahimi ◽  
Seyed Ali Asghar Akbari Mousavi ◽  
Mostafa Soltan Bayazidi ◽  
Mohammad Mastoori
Keyword(s):  
Feeding Rate ◽  
Surface Defects ◽  
Numerical Study ◽  
Internal Diameter ◽  
The Finite Element Method ◽  
Forming Process ◽  
Flow Forming ◽  
Cold Forming ◽  
External Variables ◽  
Experimental Process

Flow forming is one of the cold forming process which is used for hollow symmetrical shapes. In this paper, the forward flow forming process is simulated using the finite element method and its results are compared with the experimental process. The variation of thickness of the sample is examined by the ultrasonic tests for the five locations of the tubes. To simulate the process, the ABAQUS explicit is used. The effects of flow forming variables such as the angle of rollers and rate of feeding of rollers, on the external variables such as internal diameter, thickness of tube and roller forces are considered. The study showed that the roller force and surface defects were reduced with low feeding rate and low rollers attack angles. Moreover, the sample internal diameter increased at low feeding rate and low rollers attack angles. The optimum variables for flow forming process were also obtained.

A Numerical Contour Method for Simulating Spiral Groove Bottom Profiles

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Weifeng Wu ◽  
Shuo Sun ◽  
Quanke Feng
Keyword(s):  
Surface Profile ◽  
Contour Method ◽  
Contact Lines ◽  
Spiral Groove ◽  
Groove Surface ◽  
Contact Points ◽  
Envelope Method ◽  
Twin Screw ◽  
Rotor Profiles ◽  
Boundary Contact

The envelope method can be used to model the spiral groove surface profile in single screw compressors produced by cylindrical milling using the contact lines of the cutter surface and the groove. However, the envelope method cannot predict the groove bottom profile accurately because it does not account for the boundary contact lines on the end face of the cutter. A new numerical contour method is proposed to model the groove bottom profile by identifying the contact points on the end face of the cutter to a set position on the spiral groove. Results show that the new method can calculate accurately both the boundary and the inner contact line and thus simulate the groove bottom profile exactly. This method could also be used to simulate other profiles of machines, such as rotor profiles of twin screw compressors and screw pumps.

Real-Time 2D Surface Profile Mapping of Biological Tissue with Force Feedback in Robot-Assisted Minimally Invasive Surgery

2015 ◽  
Vol 798 ◽  
pp. 319-323
Author(s):  
Ali Reza Hassan Beiglou ◽  
Javad Dargahi
Keyword(s):  
Minimally Invasive Surgery ◽  
Minimally Invasive ◽  
Real Time ◽  
Invasive Surgery ◽  
Strain Gauge ◽  
Force Feedback ◽  
Surface Profile ◽  
Robot Assisted ◽  
Contact Points ◽  
Force Signal

It has been more than 20 years that robot-assisted minimally invasive surgery (RMIS) has brought remarkable accuracy and dexterity for surgeons along with the decreasing trauma for the patients. In this paper a novel method of the tissue’s surface profile mapping is proposed. The tissue surface profile plays an important role for material identification during RMIS. It is shown how by integrating the force feedback into robot controller the surface profile of the tissue can be obtained with force feedback scanning. The experiment setup includes a 5 degree of freedoms (DOFs) robot which is equipped with a strain-gauge ball caster as the force feedback. Robot joint encoders signals and the captured force signal of the strain-gauge are transferred to developed surface transformation algorithm (STA). The real-time geometrical transformation process is triggered with force signal to identify contact points between the ball caster and the artificial tissue. The 2D surface profile of tissue will be mapped based on these contact points. Real-time capability of the proposed system is evaluated experimentally for the artifical tissues in a designed test rig.

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