| 0. Complete issue |
- 1. Optimal Design of Tube Branch Joints for Satisfactory Fatigue Life and Cost
- Pages: 033-046
- Heikki MARTIKKA, Ilkka PÖLLÄNEN
- Abstract | Download | View
Abstract
This paper presents results of using a unified methodology of combining heuristic fuzzy optimum design and
FEM verification to design optimally tube branch joints. The joint is loaded by bending moment on the pipe.
These joints are needed as safety critical parts in recovery boiler heat transfer tube platens.
First, design variable options are defined as dimensionless and discrete. The first is the ratio of mean radius of pipe to
mean radius of header radius. The second is the ratio of header wall thickness to the inner header radius.
Second, the decision variables are formulated based on these design variables. Decision variables are material cost
and Paris life for crack propagation. Realistic fatigue life estimates are obtained by considering that the loads are
stochastic around the mean stress amplitudes. The stochasticity of loading reduces fatigue life by reduction factors in
the range 2 to 4.The methods are used to obtain estimates of factors. Thirdly the total design goal is formulated as
maximization of the end user fuzzy satisfaction on the design. The goal function is the product of satisfaction functions
of decision variables. The stresses are calculated using reasonable free body models and stress concentration factor
Kt. It is modelled as a regression model obtained by several FEM analyses depending on the two main design variables.
Each design is optimal at its prescribed load. The total satisfaction decreases with increasing loading, at moment 500
it is 0.36 times the satisfaction at moment 200.
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- 2. Design and Development of a Plastic Powder Processing Machine for Recycling Used Polyethylene Therephthalate
- Pages: 047-052
- Chukwunonso NWOGU, Remy UCHE, J. O. IGBOKWE, A. C. OKORONKWO
- Abstract | Download | View
Abstract
A plastic powder processing machine comprising of a frame, electric motor, melting pot, barrel, blower, tray,
hammermill, crank mechanism and temperature control circuit was designed and developed. The machine is powered by a
5hp (3.728kw) electric motor which drives the hammermill shaft. An electric heater inserted in the melting pot melts the
PET before it enters the hammermill where it is crushed to powdered form. A temperature control circuit attached to the
melting pot ensures the molten plastic does not ignite due to overheating. The machine was used to process two grades of
PET bottles i.e. grade one which is designated PET1 with intrinsic viscosity values ranging from 0.78-0.80 and grade two
which is designated PET2 with intrinsic viscosity values ranging from 0.80-0.85. PET1 gave maximum values of grain
size, throughput and conversion efficiency as: 150 μm, 2.14 kg/min and 93% respectively and minimum values as: 3.9 μm,
0.92 kg/min and 64% respectively while PET2 gave maximum values of grain size, throughput and conversion efficiency
as: 200 μm, 2.86 kg/min and 91% respectively and minimum values as: 5 μm, 1.07 kg/min and 65% respectively.
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- 3. Transient Performance of a Three-Way Pressure Reducing Valve
- Pages: 053-056
- Mihail KOMITOVSKI, Sasko DIMITROV
- Abstract | Download | View
Abstract
The article presents experimental and theoretically simulated transient processes with serially produced
three-way reduction valve with direct control NG6 of the company BoschRexroth. This class of valves is used to
maintain a reduced pressure of constant level in a secondary circuit of the hydraulic system, independent of change the
pressure of primary circuit or change of the flow through the valve. This paper deals with modeling of the transient
processes of threeway pressure reducing valves by changes of the flow through the valve. The validity of the proposed
model is assessed experimentally. The study aims to point out the transient change of the clamping force in hydraulic
systems with three-way pressure valve
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- 4. Design Solution and Calculation of Important Elements of Hand Drill and Angle Grinder Table Stan
- Pages: 059-062
- Milan TICA, Nikola RADULOVIĆ, Milan BANIĆ, Aleksandar MILTENOVIĆ, Milan RACKOV
- Abstract | Download | View
Abstract
Design solution of hand drill and angle grinder table stand was developed by using modern approach to
product development. Chosen solution represents an optimal one based on two factor criteria. Sketch and 3D model are
presented, and critical elements of assembly are identified. Estimation of possible external loads is used to calculate
loads on each element. Software package SOLIDWORKS was used for modeling and simulation. Based on simulation
results, shape optimization was performed. Work documentation was made and next step should be prototype
manufacturing and testing.
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- 5. Design of Winches for Depth Sensors Rope
- Pages: 063-066
- Dusan JESIC, Pavel KOVAC, Borislav SAVKOVIC, Nenad KULUNDZIC
- Abstract | Download | View
Abstract
In fact, all very complex machines consist of so-called free machines. The winch is one of the simple
machines and consists of a horizontal roller that rotates in its blades. A roller is rolled on the roller whose one end is
fixed to the roller, and on the other the load is higher. There are various constructive solutions of the mentioned device.
Calculation of winch load is in the paper shown as well. It is especially important to pay attention to the choice of the
material as well as the connection between the plates and the shaft when connecting pipes and axles representing the
drum of winch.
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