Formability evaluation of dimple forming process based on numerical and experimental approach

2011 ◽  
Vol 25 (2) ◽  
pp. 429-439 ◽  
Author(s):  
Seong-Chan Heo ◽  
Young-Ho Seo ◽  
Tae-Wan Ku ◽  
Beom-Soo Kang
Keyword(s):  
Experimental Approach ◽  
Forming Process

Influencing Factors of AZ31B Sheet Deep Drawing

2011 ◽  
Vol 189-193 ◽  
pp. 88-91
Author(s):  
Jun Gao ◽  
Zhen Ming Yue ◽  
Shu Xia Lin
Keyword(s):  
Numerical Simulation ◽  
Deep Drawing ◽  
Experimental Approach ◽  
Elevated Temperatures ◽  
Heating Temperature ◽  
Thickness Distribution ◽  
Simulation Software ◽  
Forming Limit ◽  
Forming Process ◽  
Specific Strength

Magnesium alloys have been attracting much more attentions due to its low density, high specific strength and its lightweight during the past 30 years. In this paper, the deep drawing performance of AZ31B magnisium alloy sheets at elevated temperature was studied by the experimental approach. The results indicated that the formability of the AZ31B sheets at elevated temperatures could be improved significantly. The best external forming parameters can be obtained such as heating temperature of sheet, die-punch clearance, punch fillet radius, etc. Simulating the forming process by using the numerical simulation software, we investigated the stress-strain distribution, thickness distribution and forming limit, etc. The thickness distribution by the numerical simulation agrees well with the experimental results.

Investigation on the Effect of Liquid Hammer Geometry to the Pressure Distribution of Innovative Hybrid Impact Hydroforming

2014 ◽  
Vol 941-944 ◽  
pp. 1843-1849 ◽  
Author(s):  
Murhaf Marai ◽  
Li Hui Lang ◽  
Shao Hua Wang ◽  
Li Jin Lin ◽  
Chun Lei Yang ◽  
...  
Keyword(s):  
Loading Condition ◽  
Experimental Approach ◽  
High Energy ◽  
Geometrical Shape ◽  
Wave Loading ◽  
Forming Process ◽  
Short Time ◽  
The Impact ◽  
Complex Parts

The innovative hybrid impact hydroforming (IHF) technology is a kind of high energy forming technique which can be used for forming complex parts with small features, such as convex tables, bars etc. which are widely employed in automotive and aircraft industries. The impact hydroforming technology means the most features are formed by hydroforming and the small features are rapidly reshaped by high intensity impact energy in a very short time after the traditional hydroforming. The impact pressure rises to the peak in 10ms which belongs to dynamic loading. The present work investigates IHF using a numerical /experimental approach. Finite element simulations using MSC.Patran were carried out changing the geometrical shape of liquid hammer.. Using this shock wave loading condition we did forming experiments. During forming process, stress distribution in the blank is comparatively better as compared with traditional methods so possibility of fracture is reduced. Inertia is also an important factor which affects control quality. Therefore, the research is very useful for improving forming quality of complicated products. It will be widely applied in automotive and aircraft industries.

A Numerical/Experimental Approach to Software Development for Thermoforming Simulations (Survey Paper)

1991 ◽  
Vol 113 (1) ◽  
pp. 102-114 ◽  
Author(s):  
H. G. deLorenzi ◽  
H. F. Nied ◽  
C. A. Taylor
Keyword(s):  
Experimental Approach ◽  
Large Deformations ◽  
Simulation Software ◽  
Material Behavior ◽  
Critical Parameters ◽  
Elastic Membrane ◽  
Forming Process ◽  
Survey Paper ◽  
Thermoforming Process ◽  
The One

This paper describes a combined numerical and experimental approach to the development of a software package for simulating the thermoforming process. In this process thin polymer sheets are forced under pressure into a mold cavity. During the forming process the polymer is subjected to large deformations, which result in severe nonuniform thinning. The development of the simulation software was facilitated by a close interaction between numerical modeling and experiment. On the one hand, experimental results guided the development of the software, and on the other hand, numerical developments have been used to suggest new experiments to be performed and critical quantities to be measured. The numerical software is based on the finite element method and the hot polymer is modeled as a nonlinear elastic membrane. Because of the very large deformations occurring in this process, a rigorous large deformation theory has been employed. The numerical formulation also contains contact capabilities for contact between the polymer and the mold and for contact between different parts of the polymer itself. Since very little was known about the physical processes before the program was started, especially about the material behavior and temperatures involved, carefully planned experiments were carried out to guide the selection of the material models used in the software. Since there also was a widespread misconception about the nature of some of the process parameters involved, numerical calculations were used to suggest measurements to be performed on some of these critical parameters. Excellent correlation between calculations and experiment have been obtained and are presented in the paper.

scholarly journals An experimental approach to reproduce in-plane fiber waviness in thermoplastic composites test coupons using a reverse forming method

2021 ◽  
pp. 002199832110267
Author(s):  
RDR Sitohang ◽  
WJB Grouve ◽  
LL Warnet ◽  
S Koussios ◽  
R Akkerman
Keyword(s):  
Experimental Approach ◽  
Mechanical Performance ◽  
Thermoplastic Composite ◽  
Thermoplastic Composites ◽  
Forming Process ◽  
Fiber Waviness ◽  
Manufacturing Method ◽  
Main Challenge ◽  
Defective Region ◽  
Bend Angles

In-plane fiber waviness is one of the defects that can occur from the stamp-forming process of thermoplastic composite (TPC) parts. The influence of this defect on the mechanical performance of multidirectional composites is not yet fully understood. The main challenge in determining the influence on mechanical properties lies in reproducing the waviness in test coupons that can subsequently be subjected to testing. This paper describes an experimental approach to reproduce representative in-plane waviness defects, specific for TPC, by reverse-forming of V-shape parts of various bend angles and inner radii. Characterization results show that this method enables the manufacturing of localized in-plane waviness in flat 24-ply quasi-isotropic C/PEEK composites with no voids. Furthermore, laminates having varying levels of maximum waviness angle ([Formula: see text]), between 14° to 64°, were successfully produced in this work. By comparing the [Formula: see text] value with the examples of industrial stamp-formed parts, it can be concluded that the developed coupon manufacturing method can reproduce waviness from TPC part production reasonably well. Finally, all of the produced laminates have defective region lengths smaller than 20 mm, localized within a predefined location which makes them well suited for standard compression test coupons.

The Potentials of Scanning Microscopy

1968 ◽  
Vol 26 ◽  
pp. 352-353
Author(s):  
A. V. Crewe
Keyword(s):  
Salient Feature ◽  
Secondary Emission ◽  
Resolving Power ◽  
X Rays ◽  
Scanning Microscope ◽  
Forming Process ◽  
Additional Tool ◽  
Detection Systems ◽  
Conventional Microscope ◽  
Present Information

If the resolving power of a scanning electron microscope can be improved until it is comparable to that of a conventional microscope, it would serve as a valuable additional tool in many investigations.The salient feature of scanning microscopes is that the image-forming process takes place before the electrons strike the specimen. This means that several different detection systems can be employed in order to present information about the specimen. In our own particular work we have concentrated on the use of energy loss information in the beam which is transmitted through the specimen, but there are also numerous other possibilities (such as secondary emission, generation of X-rays, and cathode luminescence).Another difference between the pictures one would obtain from the scanning microscope and those obtained from a conventional microscope is that the diffraction phenomena are totally different. The only diffraction phenomena which would be seen in the scanning microscope are those which exist in the beam itself, and not those produced by the specimen.

Experimental Determination of the Effective Resolution Limit in Thick Specimens at High Voltages

1975 ◽  
Vol 33 ◽  
pp. 664-665
Author(s):  
Mircea Fotino
Keyword(s):  
Experimental Approach ◽  
Chromatic Aberration ◽  
Resolving Power ◽  
Biological Research ◽  
Specimen Thickness ◽  
Resolution Limit ◽  
High Voltage Electron Microscopy ◽  
Voltage Electron ◽  
Resolution Level

The use of thick specimens (0.5 μm to 5.0 μm or more) is one of the most resourceful applications of high-voltage electron microscopy in biological research. However, the energy loss experienced by the electron beam in the specimen results in chromatic aberration and thus in a deterioration of the effective resolving power. This sets a limit to the maximum usable specimen thickness when investigating structures requiring a certain resolution level.An experimental approach is here described in which the deterioration of the resolving power as a function of specimen thickness is determined. In a manner similar to the Rayleigh criterion in which two image points are considered resolved at the resolution limit when their profiles overlap such that the minimum of one coincides with the maximum of the other, the resolution attainable in thick sections can be measured by the distance from minimum to maximum (or, equivalently, from 10% to 90% maximum) of the broadened profile of a well-defined step-like object placed on the specimen.

Microscopy of porous ceramics

1989 ◽  
Vol 47 ◽  
pp. 438-439
Author(s):  
H. M. Kerch ◽  
R. A. Gerhardt
Keyword(s):  
Porous Ceramics ◽  
Specimen Preparation ◽  
High Porosity ◽  
Ion Milling ◽  
Forming Process ◽  
Preparation Methods ◽  
Pore Texture ◽  
Proper Design ◽  
And Function ◽  
Function Information

Highly porous ceramics are employed in a variety of engineering applications due to their unique mechanical, optical, and electrical characteristics. In order to achieve proper design and function, information about the pore structure must be obtained. Parameters of importance include pore size, pore volume, and size distribution, as well as pore texture and geometry. A quantitative determination of these features for high porosity materials by a microscopic technique is usually not done because artifacts introduced by either the sample preparation method or the image forming process of the microscope make interpretation difficult.Scanning electron microscopy for both fractured and polished surfaces has been utilized extensively for examining pore structures. However, there is uncertainty in distinguishing between topography and pores for the fractured specimen and sample pullout obscures the true morphology for samples that are polished. In addition, very small pores (nm range) cannot be resolved in the S.E.M. On the other hand, T.E.M. has better resolution but the specimen preparation methods involved such as powder dispersion, ion milling, and chemical etching may incur problems ranging from preferential widening of pores to partial or complete destruction of the pore network.

Malfunctional Reorganization in the Developing Limbo-Prefrontal System in Animals: Implications for Human Psychoses?

2001 ◽  
Vol 12 (1) ◽  
pp. 8-14
Author(s):  
Gertraud Teuchert-Noodt ◽  
Ralf R. Dawirs
Keyword(s):  
Prefrontal Cortex ◽  
Mental Disorders ◽  
Dentate Gyrus ◽  
Cognitive Functions ◽  
Experimental Approach ◽  
Regulatory Mechanisms ◽  
Hippocampal Dentate Gyrus ◽  
Non Invasive ◽  
Invasive Method ◽  
Activity Dependent

Abstract: Neuroplasticity research in connection with mental disorders has recently bridged the gap between basic neurobiology and applied neuropsychology. A non-invasive method in the gerbil (Meriones unguiculus) - the restricted versus enriched breading and the systemically applied single methamphetamine dose - offers an experimental approach to investigate psychoses. Acts of intervening affirm an activity dependent malfunctional reorganization in the prefrontal cortex and in the hippocampal dentate gyrus and reveal the dopamine position as being critical for the disruption of interactions between the areas concerned. From the extent of plasticity effects the probability and risk of psycho-cognitive development may be derived. Advance may be expected from insights into regulatory mechanisms of neurogenesis in the hippocampal dentate gyrus which is obviously to meet the necessary requirements to promote psycho-cognitive functions/malfunctions via the limbo-prefrontal circuit.

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