Elastic-Plastic Analysis of Thermoplastic Composite
Plate subjected to Transverse Load
-
Lalitha Chattopadhyay and Shiva Shankar R
Contact : lalitha@nal.res.in
Abstract :
In this work, an elastic-plastic stress analysis was carried out on
thermoplastic composite laminate analytically using classical lamination
plate theory for small plastic deformation and plane stress case. The
composite material is assumed to be strain-hardening. The Tsai-Hill theory
is used as yield criteria. Elastic and elastic-plastic stresses were
calculated for thermoplastic laminated composite considering simply
supported plate subjected to uniform transverse load with different ply
orientations.
Performance Evaluation of
Podded Propulsors in Four Quadrants of Operation
- Mohammed Islam,
Ayhan Akinturk and Brian Veitch
Contact : islam.mohammed@oceaniccrop.com
Abstract : This paper presents experimental
results of the performance characteristics of a podded propulsor model.
Fundamental research has been carried out to evaluate the effect of presence
of pod-strut body on the propulsive performance in open water condition and
in four quadrants of operation. Two cases are examined, namely: propeller
only case and propeller-pod-strut (pod unit) case. In the propeller only
case, a standard Kemp and Rammer dynamometer is used to measure the thrust
and torque of the propeller. In the pod unit case, a pod-strut body fitted
with the same propeller is experimented using a custom-made pod dynamometer
system in the same facility. Measurements are made on the propeller thrust
and torque as well as the unit forces and moments in the three coordinate
directions and in the four quadrants of operation. The propulsive
characteristics of the propellers in the two cases are found comparable in
the four-quadrants. The effect of the pod-strut body on both thrust and
torque of the propeller is found very evident. Detail uncertainty analysis
is carried out for both measurements and is found within the acceptable
limits. The presented data can be valuable for design of podded propulsor
and CFD benchmarking for performance analysis.
Dimensional Analysis for Prediction of Line
Heating Residual Deformations
- Pankaj Biswas and N.R. Mandal
Abstract : Line heating
process is a very complex phenomenon as a variety of factors affects the
amount of residual deformations. Numerical thermal and mechanical analysis
of line heating for prediction of residual deformation is time consuming. In
the present work dimensional analysis has been presented to obtain a
relationship between input parameters and resulting residual deformations
during line heating process. The temperature distribution and residual
deformations for 6mm, 8mm, 10mm and 12mm thick steel plates were numerically
estimated and compared with experimental and published results. Extensive
data generated through a validated FE model were used to find
co-relationship between the input parameters and the resulting residual
deformations by multiple regression analysis. The results obtained from the
deformation equations developed in this work compared well with those of the
FE analysis with a drop in the computation time in the order of 100
(computational time required for FE analysis is around 7200 seconds to 9000
seconds, whereas the time required using the nondimensional equations is
only 60 to 90 seconds).
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