On the Dynamic Expansion of a Circular Hole in an Infinite Plate of Rate-Sensitive Plastic Material

1978 ◽  
Vol 45 (1) ◽  
pp. 67-72 ◽  
Author(s):  
P. C. Upadhyay ◽  
V. K. Stokes
Keyword(s):  
Circular Hole ◽  
Exponential Type ◽  
Material Properties ◽  
Method Of Characteristics ◽  
Numerical Solutions ◽  
Plastic Material ◽  
Infinite Plate ◽  
Constant Acceleration ◽  
Plastic Materials ◽  
Wide Range

The dynamic expansion of a circular hole in an infinite plate has been considered for rate-sensitive plastic materials by using an elastic-visco-perfertly plastic model of the exponential type. Numerical solutions have been obtained, by the method of characteristics, for the case when the hole is subjected to a constant acceleration. Solutions have been presented in the form of nondimensional plots covering a wide range of material properties and accelerations.

The Dynamic Hole Expansion Problem for a Plate of Elastic-Perfectly Plastic Material

1978 ◽  
Vol 45 (4) ◽  
pp. 961-963
Author(s):  
P. C. Upadhyay ◽  
V. K. Stokes
Keyword(s):  
Circular Hole ◽  
Numerical Solutions ◽  
Plastic Material ◽  
Plastic Region ◽  
Infinite Plate ◽  
Tangential Component ◽  
Constant Acceleration ◽  
Perfectly Plastic ◽  
Hole Boundary ◽  
Elastic Perfectly Plastic

Numerical solutions have been obtained for the problem of the dynamic expansion of a circular hole in an infinite plate of elastic-perfectly plastic material, due to the imposition of a constant acceleration at the hole boundary, for three different materials. It has been shown that Freiberger’s assumption, concerning the vanishing of the tangential component of stress in the plastic region, is not valid.

An Elongating String Under the Action of a Transverse Force

1957 ◽  
Vol 24 (4) ◽  
pp. 609-616
Author(s):  
Werner Goldsmith
Keyword(s):  
Method Of Characteristics ◽  
Numerical Solutions ◽  
Transverse Force ◽  
Transverse Displacement ◽  
Fixed Frequency ◽  
Constant Acceleration ◽  
Forcing Function ◽  
Subsonic Regime ◽  
Arbitrary Amplitude ◽  
Analytical Expressions

Abstract The motion of a uniform undamped flexible string whose length increases with time has been investigated when an arbitrary time-dependent force acts transversely at the free end. The method of characteristics has been employed to derive analytical expressions for the transverse displacement in the subsonic regime. Cases are considered when the free end of the wire moves either at constant velocity or at constant acceleration. Numerical solutions are presented in dimensionless form for a sinusoidal forcing function of arbitrary amplitude and fixed frequency. The possibility of the existence of resonances in the string has been examined.

scholarly journals On the solution of asymptotic impact problems with significant localised indentation

2016 ◽  
Vol 231 (5) ◽  
pp. 807-822 ◽  
Author(s):  
Akuro Big-Alabo ◽  
Matthew P Cartmell ◽  
Philip Harrison
Keyword(s):  
Numerical Solutions ◽  
Nonlinear Models ◽  
Infinite Plate ◽  
Nonlinear Odes ◽  
Wide Range ◽  
Contact Models ◽  
Scope Of Application ◽  
Impact Problems ◽  
The Impact ◽  
Impact Events

A major challenge in studying impact problems analytically is solving the governing equations of impact events, which are mostly in the form of nonlinear ODEs. This paper focuses on the solution of nonlinear models for impact problems in asymptotic cases, where local indentation is significant. The asymptotic cases consist of both half-space and infinite plate impacts, which cover a wide range of practical impact events. A so-called force–indentation linearisation method (FILM), first described in a previous study, is reformulated here in a more general form in order to broaden its scope of application. The generalisation of the FILM facilitates stable and convergent solutions even when complex nonlinear contact models are used to estimate the impact force. Simulations based on the FILM approach are validated using numerical solutions.

scholarly journals Additive Technology Parts and their Material Properties

2019 ◽  
Vol 16 (1) ◽  
pp. 58-61
Author(s):  
Juraj Beniak ◽  
Miloš Matúš ◽  
Peter Križan ◽  
Michal Holdy
Keyword(s):  
Fused Deposition Modeling ◽  
Plastic Material ◽  
Acrylonitrile Butadiene Styrene ◽  
Additive Technology ◽  
Modeling Technology ◽  
Fused Deposition ◽  
Steel Material ◽  
Plastic Materials ◽  
Wide Range ◽  
Plastic Parts

Abstract Additive technology uses a wide range of materials. Beginning from plastic material, different types of resin but also steel material. Presented paper deals with Fused Deposition Modeling technology which is focused to processing of plastic materials based on polymers. Mostly used are ABS plastic (Acrylonitrile Butadiene Styrene), Nylon, Polycarbonate (PC), or composites based on different polymers. New devices designed for the production of plastic parts are able to work also with environmentally friendly and biodegradable materials as Polylactic acid (PLA). The aim of this paper is to show the possibility of using materials based on organic polymers whose properties are comparable to conventionally used polymers. Presented are measured and statistically evaluated data related to basic properties of PLA material.

scholarly journals BIODEGRADABLE PLASTIC PRODUCTION FROM POLYHYDROXYBUTYRATE(PHB) PRODUCING BACTERIA AND ITS IMPACT ON ENVIRONMENT.

2021 ◽  
pp. 584-593
Author(s):  
Hiral Shah ◽  
Nidhi Gondaliya ◽  
Richa Soni
Keyword(s):  
Plastic Material ◽  
Carbon Sources ◽  
Packaging Material ◽  
Natural Polymer ◽  
Reserve Material ◽  
Plastic Materials ◽  
Wide Range ◽  
Micro Organisms ◽  
Agro Residues ◽  
Plastic Products

Plastic materials have been used in various ways such as packaging material, glass wares, certain parts of instruments of various grades, many more. As plastic products are not easily decomposed and accumulate in environment. This has created an adverse effect on our ecosystem. Bioplastics are best alternative to overcome these issues and reduce damages in ecosystem. Bioplastics are easily and speedily degrade under natural environmental conditions. Polyhydroxybutyrate or PHB is a bioplastic, one of the best natural polymer and alternative of synthetic plastic material. Bioplastic are comparative more flexible to convert into various forms also. Normally, it is a lipid reserve material produce in adverse or under stress conditions and stored within the cell wall of micro-organisms. Poly-3-hydroxybutyrate (PHB) is a natural biopolymer produce by wide range of microbes which is a storage granule used by microbes as an energy as well as carbon source.this microbes includes from extremophiles to mesophiles. The objective of our work was to isolate potential PHB producing bacteria using agro-residues as carbon sources within natural environment conditions. This work describes the understanding of microbes that are involved in the degradation of both natural and synthetic polymers.Also to contribute in green environment by providing eco- friendly product.

A Comparison of Deformation and Flow Theories Under Dynamic Loading Conditions

1978 ◽  
Vol 45 (2) ◽  
pp. 431-433
Author(s):  
P. C. Upadhyay ◽  
V. K. Stokes
Keyword(s):  
Deformation Theory ◽  
Numerical Solutions ◽  
Infinite Plate ◽  
Theory Model ◽  
Loading Conditions ◽  
Constant Acceleration ◽  
Stress Strain Relation ◽  
Flow Theories ◽  
Hole Boundary ◽  
Dynamic Loading Conditions

Numerical solutions have been obtained for the problem of the dynamic expansion of a circular hole in an infinite plate, due to the imposition of a constant acceleration at the hole boundary, for a deformation theory model based on the Ramberg-Osgood stress-strain relation. In order to assess the validity of using deformation theories for problems in which dynamic plastic deformations may occur under nonproportional loading conditions, these solutions have been compared with those for the equivalent flow theory model.

Influence of the Recycled Material Percentage on the Mechanical Behaviour of HDPE for Injection Moulding Process for an Ecologycal Design

2012 ◽  
Vol 445 ◽  
pp. 935-940 ◽  
Author(s):  
Carlos Javierre ◽  
Angel Fernandez ◽  
Victor Camanes
Keyword(s):  
Mechanical Behaviour ◽  
Material Properties ◽  
Injection Moulding ◽  
Plastic Material ◽  
Young Modulus ◽  
Raw Material ◽  
Moulding Process ◽  
Plastic Materials ◽  
Injection Moulding Process ◽  
Recycled Material

Nowadays plastic materials recycling aims most of the time to use the recycled material to manufacture products of less requirements than the original products, so the material is depreciated. It would be important to recycle plastic materials to use them for the same applications they were initially used. To make this possible it would be necessary to characterize the recycled material properties, design products taking into account that they are going to be produced with recycled material and to be able to recuperate the product at the end of its lifetime. An example of this designing philosophy is going to be presented in this work, applied to large trash containers produced withHDPE (RIGIDEX5740UA), where the product can be easily recovered at the end of its lifetime and also the amount of polymer material wasted during thermoplastic injection moulding is very high. Recycling mills convert parts into small pieces that are used as feed material for injection again, by mixing it in different percentages with raw material. This mixture of both raw and recycled material modifies material properties according to the percentage of recycled material introduced. Some of the properties affected by this modification are those related to mechanical behaviour. This paper analyzes the mechanical behaviour of material with different percentages of recycled material. Test parts have been injected with different percentage of recycled material and have been tested by a tensile machine. Results like; Stress at yield, Stress at break and Young Modulus have been calculated and analysed. The product of this work has been designed using only one plastic material, which is very helpful from the point of view of manufacturing and recycling.In these kinds of parts a very tight safety factor is used, thats why to know exactly material properties is very important during its design.

Thermal Post-Buckling Analysis of Functionally Graded Composite Plates with Nonlinear Aerodynamic Forces

2010 ◽  
Vol 123-125 ◽  
pp. 280-283
Author(s):  
Chang Yull Lee ◽  
Ji Hwan Kim
Keyword(s):  
Material Properties ◽  
Numerical Solutions ◽  
Virtual Work ◽  
Shear Deformation Theory ◽  
Composite Plates ◽  
Buckling Analysis ◽  
Functionally Graded ◽  
Governing Equations ◽  
Functionally Graded Composite ◽  
Post Buckling

The post-buckling of the functionally graded composite plate under thermal environment with aerodynamic loading is studied. The structural model has three layers with ceramic, FGM and metal, respectively. The outer layers of the sandwich plate are different homogeneous and isotropic material properties for ceramic and metal. Whereas the core is FGM layer, material properties vary continuously from one interface to the other in the thickness direction according to a simple power law distribution in terms of the volume fractions. Governing equations are derived by using the principle of virtual work and numerical solutions are solved through a finite element method. The first-order shear deformation theory and von-Karman strain-displacement relations are based to derive governing equations of the plate. Aerodynamic effects are dealt by adopting nonlinear third-order piston theory for structural and aerodynamic nonlinearity. The Newton-Raphson iterative method applied for solving the nonlinear equations of the thermal post-buckling analysis

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