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On the Rapid Prototyping Technologies and Applications in Product Design and Manufacturing Pulak M Pandey Department of Mechanical Engineering Indian Institute of Technology Delhi, India, Pin:110016 Email: pmpandey@mech.iitd.ac.in Keywords: Solid modeling, Tessellation, Deposition, Prototyping, Stereolithography, Selective Laser Sintering, Fused Deposition Modeling, Laminated Object Manufacturing.
Second phase of prototyping started around mid-1970s, when a soft prototype modeled by 3D curves and surfaces could be stressed in virtual environment, simulated and tested with exact material and other properties.
At this stage choice of part deposition orientation [4-7] is the most important factor as part building time, surface quality, amount of support structures, cost etc. are influenced.
The laser is modulated in such away that only those grains, which are in direct contact with the beam, are affected [10].
Various important factors need to be considered and are steady nozzle and material extrusion rates, addition of support structures for overhanging features and speed of the nozzle head, which affects the slice thickness.

Khattak1,e 1 Faculty of Mechanical Engineering, Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia a esah@fkm.utm.my, bknia_ismail@yahoo.com, cjasmi@fkm.utm.my, deng_forever88@hotmail.com, eadil@fkm.utm.my Keywords: solution annealed, ageing treatment, superelasticity.
From a practical point of view this alloy is the most attractive one among many shape memory alloys due to their unique properties such as excellent shape memory effect and superelasticity [1-5].
The deformation characteristics are affected by a number of factors, including the alloy composition [6], the heat treatment processes [7], the deforming temperature [8], and the stress–strain cycle [9].
On the other hand, R phase transformation has a significant smaller lattice deformation and is much less affected by the presence of particles.
It is noticed that the presence of austenite is the important factor that superelasticity could occurred.

The mechanical properties of ultra-fine grained and nanocrystalline materials, therefore, can be severely affected by the dynamic behavior of grain boundaries.
Coupling between grain boundary migration and produced shear is characterized by the factor determined as β=γ=s/d.
Moreover, the experimental results have verified the prediction of the model by Cahn et al. [14,15] that the tangent rule for calculation of the coupling factor β retains its validity over the entire misorientation range including the high angle regime: as depicted in Fig. 2a, the values of the coupling factor calculated according to the model are in excellent agreement with the values obtained in the experiment.
(a) Measured (points) and calculated (lines) coupling factors β and (b) activation enthalpy H of stress driven migration vs. misorientation angle θ for symmetrical <100> tilt grain boundaries [28].
Contrary to this prediction, the experiments with <100> tilt boundaries [31] as well as measurements on bicrystals with <111> tilt boundaries [32], showed that the asymmetrical tilt boundaries can move under an applied stress and produce a shear, although the obtained coupling factors distinctly deviated from the coupling factor calculated according to the tangent rule.

However, the presence of corrosive species such as HCl, H2O, CO H2S, SO2, chlorides, sulphides, hydrocarbons etc. [1] is a critical factor causing corrosion degradation at elevated or high temperatures.
Corrosion problems in waste incinerators or co-combustion boilers are very complicated due to many factors such as: • complicated combustion atmospheres which contain aggressive corrosion species such as: HCl, SO2, SO3, H2O, CO2, CO, NOx, sulphides, chlorides, dust, fly ash, etc. [1-3] • presence in the flue gas of volatile products such as alkali and heavy metal oxides (e.g.
Na2O, K2O, ZnO, PbO), alkali chlorides (NaCl, KCl) and sulphates (Na2SO4, K2SO4, ZnSO4 and PbSO4) • flue gas velocity fluctuations, which can affect the mechanism and rate of corrosion, especially when volatile species can form [4] • temperature fluctuations (which mainly affect material stress, but can also change the corrosion rate and mechanism) • inhomogeneous waste composition used in combustion processes (e.g. biomass, PVC, domestic refuse, rubber, batteries, etc
Koukkari et al.: Microstructures, Mechanical Properties and Processes (Euromat 99 - Vol. 3, Wiley-VCH Publishers, Weinheim, 2000)

Introduction Ultra-fine grained materials offer significant advantages in terms of high strain rate superplasticity and improved mechanical properties, compared to materials with conventional grain sizes [1].
These factors have led to a significant commercial interest in severe deformation processing.
This effect has previously been used to obtain superplastic properties in conventionally rolled sheet materials [10].
Other fundamental material properties also have a significant effect on the formation of an ultrafine grain structure during severe deformation.
These factors will require further investigation before successful commercial processes can be developed.

Recursive application of this approach to the coarse problem produces a true multigrid method, which has the property that a problem can be solved easily.
A convergence factor which is the relative residual norm is 10-7 for all cases.
Mechanical part (model 3) Fig. 2(c) shows a coarsest mesh of a mechanical part and its boundary condition.
Residual in case of mechanical part for 182,484 freedoms.
It is found from the result that these very slight differences largely affect convergence in the bending cantilever problems.

As the typical of morden ground fissure in our country, there has been already more than 400 ground fissures found in Fenwei Basin, making it be one of the most developed ground fissure disaster areas in our country[2], and seriously affects the city's construction and development of national economy.
In recent years, because of the human water-related activities, underground energy resources exploitment, human engineering activities seismic effect and other uncertain factors, ground fissure disasters are becoming more and more serious.
But the dynamic characteristics of ground fissure research fields, such as ground seismic amplification effect of the ground fissures, has been less stepped into, and in this weak links of the ground fissures, the achievement is few and there is no consolidated understanding on the selection of the parameter of ground dynamic properties.
In this model, the soil was treated as a visco-elasticity body and the equivalent shear modulusand equivalent damping ratios are employed to reflect the nonlinearity and hysteresis of the dynamic soil stress-strain relationship, and the backbone curve express the relationship between the maximum shear stress and the maximum shear strain, which reflects the nonlinearity of the dynamic stress-strain relationship .As for hysteretic curve, it expresses the relationship between shear stress and shear strain within a certain stress cycle of each moment, at the same time, reflects the dynamic stress of dynamic strain hysteresis. 3 Experimental schemes Taken from Chang'an ground fissures footwall of Xi'an metro line 4, the test loess are 12~12.5m in depth and 6m far away from ground fissures in horizontal direction, the basic physical and mechanical properties are shown in table 1.
Table 1 Physical and mechanical properties of the sample Natural density ρ[g∕cm3] proportion Gs Plastic limit wp[%] Liquid limit wl[%] Void ratio e0 1.800 2.71 19.4 32.3 17.15 Testing on STD-10 vibration triaxial test system, soil samples are cylindrical specimens of 39.1 mm in diameter and 80 mm in height.

Fig.1 Contour and thickness distribution of Fig. 2 Grid of model of violin front and back plate sounding box The Material Properties of Violin Sounding Box.
In finite element analysis, material properties have great impact on the results of simulation.
In this paper, mechanical performance parameters of spruce and maple are adopted from literature [8], they are shown in Table1.
Table 1 Material properties of violin sounding box applied in finite element method material Density (kg/m3) Young modulus (MPa) Shear modulus (MPa) Poisson's ratio X Y Z XY YZ XZ XY YZ XZ maple spruce 540 410 12430 7590 833 592 1740 326.4 920 463 311 486 1106 22.8 0.509 0.245 0.354 0.372 0.434 0.467 Modal Analysis of Violin Sounding Box.
In order to study the factors that influence the vibration of violin sounding box, this paper selects different front plates in Table 2 to make up violin sounding box.

But, thanks to its unique technical and operational properties, the plate has become more widely used.
Such unique properties and a wide range of applications attract special attention from scientists and operators from different countries who strive to constantly improve the characteristics of airfield slabs. 2 Literature Review and Problem Statement To study the load-bearing capacity and crack resistance of airfield slabs, different approaches are used [1].
Operation of airfield slabs under climatic factors and significant loads from modern types of equipment leads to surface wear and the formation of various defects, primarily cracks.
Blacha, P.Iwanowski, Analysis of load bearing capacity of cement concrete airfield pavement's construction in relation to its' changes of physico-mechanical parameters.
Kovalenko, Determination of the influence of deflections in the thickness of a composite material on its physical and mechanical properties with a local damage to its wholeness.

Introduction Most Ni-based superalloys are strengthened by the precipitation of coherent γ' precipitate, and the size and volume fraction of the γ' phase are optimized to get the desired properties.
However, since these practical superalloys are multi-component alloys other precipitates such as σ and η phases are also formed and affect the morphology of microstructure and the mechanical properties.
Therefore, the precipitation behaviour and the microstructural morphology of the coherent phases are a little complex and it is not easy to elucidate the effect of coherent phases to the whole precipitation behaviour and the mechanical properties.
The absorption effect of X-ray inside the foil was corrected by the extrapolation method [5] and their chemical compositions were estimated with the so-called Cliff-Lorimer factors [6] evaluated from the reference specimens.