Volume 18 No. 2, Oktober 2007http://hdl.handle.net/11617/8812024-03-29T06:48:58Z2024-03-29T06:48:58ZOBSERVATIONS OF THE INSTANTANEOUS NEARBED STREAMWISE FLOW VELOCITIES IN CONSTANT FLOWRATESSaadi, Yusronhttp://hdl.handle.net/11617/9582018-03-19T04:16:28Z2007-10-01T00:00:00ZOBSERVATIONS OF THE INSTANTANEOUS NEARBED STREAMWISE FLOW VELOCITIES IN CONSTANT FLOWRATES
Saadi, Yusron
Seven series of laboratory experiments were carried out in a re-circulating
glass sided tilting flume to investigate the instantaneous nearbed streamwise
flow velocities in different duration of constant flowrates. Each series were
observed at different time elapsed to represent the flow condition at different
time of bed exposures. The instantaneous nearbed streamwise flow velocities
were recorded using an Acoustic Doppler Velocimeter (ADV), which was
positioned in such a way the probe could easily traverse the grid points to
collect measurements. The experiments suggest that the instantaneous
nearbed streamwise flow velocities within the grid varied throughout the
constant flowrates with lower range of variations occurred in the shorter
tests and wider variations in the longer tests.This means the constant
flowrates produced different level of turbulences in a relatively small area
even at adjacent points. With a relatively stable standard deviations
regardless of the time elapsed of measurement it was also found that the
average values of instantaneous nearbed streamwise flow velocities are
slightly lower particularly for the shorter time interval between
measurements and generally decreased towards the end of each test. This
indicates that there was always a spatial variation in the average
instantaneous nearbed streamwise velocities throughout the test.
2007-10-01T00:00:00ZVIBRATION ANALYSIS OF DYNAMIC MODELLING OF GEAR PAIR IN MESH DUE TO TORQUE AND LOAD ON THE SYSTEMWijianto, Wijiantohttp://hdl.handle.net/11617/9572018-03-19T04:16:28Z2007-10-01T00:00:00ZVIBRATION ANALYSIS OF DYNAMIC MODELLING OF GEAR PAIR IN MESH DUE TO TORQUE AND LOAD ON THE SYSTEM
Wijianto, Wijianto
This paper presents dynamics modeling of gear pair in mesh. State space
analysis and MATLAB operation are used to obtain natural frequencies and
graphs of motion on the system. Torque load are applied to analysis
numerical integration solution. The results are compared to the one without
torque and load. The torque acts on pinion and the load acts on gear output.
The natural frequencies of the gear pair in mesh system are calculated from
the complex eigenvalues. The graphs of the gear angular velocity show that
in star-up region, angular velocity increases with its rate velocity. It was
vibrates with various amplitude. In steady state region, the gear angular has
a constant average value. Applying the mesh stiffness variation affects in the
changes of wave form and amplitude of the gear velocity vibration. The
variable value of mesh stiffness causes vibration of the gear pair in mesh
system. In addition, transmission error of the gear pair in mesh system tends
to go into a constant value after periodically change. It is still vibrates in the
gear system with the mesh stiffness variation.
2007-10-01T00:00:00ZGLUE INFILTRATION OF FREEFORM FABRICATION PRODUCT OF CAST IRON-PE/SILICA-PE COMPOSITEWidyanto, Susilo AdiTontowi, Alva EdyJamasri, JamasriRochardjo, Heru Santosahttp://hdl.handle.net/11617/9562018-03-19T04:16:42Z2007-10-01T00:00:00ZGLUE INFILTRATION OF FREEFORM FABRICATION PRODUCT OF CAST IRON-PE/SILICA-PE COMPOSITE
Widyanto, Susilo Adi; Tontowi, Alva Edy; Jamasri, Jamasri; Rochardjo, Heru Santosa
Due to the pressure-less sintering process, products of the SFF are
commonly weak so that the strengthening process is needed. This paper
reports a SFF product strengthening method with glue infiltration.
Material of the specimen used the powders of Cast iron-PE and Silica-PE
blend with particles size of 100µm (150 mesh) and 150µm (100 mesh) while
cyanoacrylate glue was used as infiltrant. The sintering process was run at
the temperature of 1350C and holding time of 2.5 hours. The product was
shaped in the tensile strength, the density and the shrinkage test specimens.
Before infiltration, a part of the specimens were burned out to increase the
pores. The experiment was also conducted to observe the influence of curing
process after infiltration on the tensile strength with varying curing
temperature which includes 500C, 750C and 1000C.
The experiment results show that the tensile strength of the cast iron-PE as
well as silica-PE composite is significantly increased by glue infiltration. An
increase in the tensile strength achieves around of 1100%.
2007-10-01T00:00:00ZCONVERGENCE STUDY OF BOUNDARY ELEMENT METHOD FOR REISSNER PLATE WITH MATERIAL NONLINEARITYSupriyono, Supriyonohttp://hdl.handle.net/11617/9552018-03-19T04:15:08Z2007-10-01T00:00:00ZCONVERGENCE STUDY OF BOUNDARY ELEMENT METHOD FOR REISSNER PLATE WITH MATERIAL NONLINEARITY
Supriyono, Supriyono
In this paper, a convergence study of shear deformable plates with material
nonlinearity is presented. The reasons behind this study are due to some
contribution made in this work. The material is assumed to undergo small
strains. The von Mises criterion is used to evaluate the plastic zone and
elastic perfectly plastic material behaviour is assumed. An initial stress
formulation is used to formulate the boundary integral equations. The
domain integral due to material nonlinearity is evaluated using a cell
discretization technique and a total incremental method is implemented to
solve the nonlinear system of equation.
2007-10-01T00:00:00Z