Key Engineering Materials
Vols. 378-379
Vols. 378-379
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Vol. 377
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Key Engineering Materials
Vols. 364-366
Vols. 364-366
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Vols. 361-363
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Vols. 359-360
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Vols. 353-358
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Vol. 352
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Vol. 351
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Key Engineering Materials Vols. 364-366
Paper Title Page
Abstract: A strain gradient dependent crystal plasticity approach is adopted to model the size effect
in the microforming process of sheet metal. To take into account the grain size effect in the
simulation, the total slip resistance in each active system was assumed to be due to a mixed
population of forest obstacles arising from both statistically stored and geometrically necessary
dislocations. The non-local crystal plasticity has been established by directly incorporating the
above slip resistance into the conventional rate-dependent crystal plasticity and implemented into
the Abaqus/Standard FE platform by developing the user subroutine UMAT. The formulation has
been recapitulated and followed by presentation of the numerical examples employing both the
local and non-local formulation. The comparison of the counterpart simulation results reveals the
grain size effect in the microforming process and demonstrates the availability of the code
developed.
1285
Abstract: The precision control of the injection process in micro injection molding demands precise
tracking of the moment that melt front passes through the nozzle so that accurate prediction of the
amount of melt being injected into the mould can be achieved. The tracking accuracy, to large
extent, depends on the processing of pressure signals followed by the identification of the critical
moment that melt front reaches the nozzle. A new adaptive Kalman filter was introduced in this
study to calculate and predict the amount of melt injected. The filter eliminated the delay error and
was more robust than other filters. The adaptive Kalman filter switches between two Qs for steadystate
and transient estimations, allowing resetting of the Kalman gain so that convergence is
speeded up in calculations. Experimental and simulation results prove the effectiveness of the
method proposed.
1292
Abstract: One of the remarkable achievements of nanotechnology is the ability to achieve
nanometric surface finishes in single-point diamond turning of high-precision components for
complex optical surfaces. A better understanding of the surface generation mechanisms is of prime
importance for the development for the prediction of the surface roughness. This paper presents a
study of mechanisms of nano-surface generation in single-point diamond turning of various types of
materials.
1296
Abstract: A method of fabricating nanotemplate and nanowires by the anodization of bulk
aluminum at room temperature is reported in this paper. Details of manufacturing processes as well
as some in-depth discussions on the formation mechanism of nano pores with reference to the
phenomena observed in experiments are presented. Effects of fabricating conditions such as the
anodization time, temperature, current intensity, voltage and features of solutions, were studied in
the experiments.
1302
Abstract: This study reports the experimental investigation on the flow imbalance phenomena
during filling symmetrical multi-cavity in injection molding of optic elements. There are two
aspects in this study: First, the flow imbalance in the eight-cavity mold with normal H-type
symmetric runners were observed and measured with aid of short-shot experiments. Second, the
effects of three processing conditions including injection speed, melt temperature and mold
temperature on flow imbalance were investigated. Flow imbalances are consistently observed and
quantitatively measured. The results have shown that proper injection speed, high melt and high
mold temperature can reduce the flow imbalance.
1306