Give detail classification of Non Newtonian fluids.
[3 marks]Derive Rheological models for Polymer melt flow.
[4 marks]Explain cone and plate viscometer to obtain flow data on polymer melts.
[7 marks]Explain short term testing of Plastics.
[3 marks]Discuss Hooke model and Newton Model showing Elongation –Time and Stress-strain behavior.
[4 marks]Explain the mathematical model using Maxwell model for Viscoelastic behavior.
[7 marks]Explain the radius of gyration of linear ideal chain.
[7 marks]Define drag flow, pressure flow, leakage flow.
[3 marks]Discuss Swelling ratios due to Shear Stresses for long capillary.
[4 marks]In a particular extruder screw the channel depth is 2.4 mm, the screw diameter is 50mm, the screw speed is 100 rev/min, the flight angle is 17o42' and the pressure varies linearly over the screw length of 1000 mm from zero at entry to 20 MN/m2 at the die entry. Estimate (a) the drag flow (b) the pressure flow (c) the total flow. the plastic has a viscosity of 210Ns/m2
[7 marks]The output of polythene from an extruder is 30 x10-6 m3/s. If the breaker plate in this extruder has 80 holes, each being 4 mm diameter and 12 mm long, estimate the pressure drop across the plate assuming the material temperature is 170°Cat this point. The shear stress is 1.2 x 105 N/m2
[3 marks]Draw the creep curve and explain its various stages.
[4 marks]With neat diagram explain Ram extruder to obtain flow data on polymer melt.
[7 marks]Which are the different forms of Fiber reinforcement in composites? Discuss.
[3 marks]Applying the Carreau model to PP, the following constants are known at 190ºC. Ƞ =23500 Ns/m2, A =0.05, n=0.33, Estimate the viscosity of PP at 230 ºC and a shear rate of 1000 T s-1. The glass transition temperature for the PP is -10 ºC.
[4 marks]Derive the expression for drag flow in detail for analysis of flow in extruder.
[7 marks]Apolypropylene beam is 100 mm long, simply supported at each end and is subjected to a load Wat its mid-span. If the maximum permissible strain in the material is to be 1.5%, calculate the largest load which may be applied so that the deflection of the beam does not exceed 5 mm in a service life of 1 year. For the beam I = 28 mm4 and Modulus is 347 MN/m2.
[3 marks]Write a note on: Kelvin/Voigt model
[4 marks]Explain the analysis of heat transfer during polymer processing.1
[7 marks]Discuss Residence Time and Relaxation Time.
[3 marks]The density of a composite made from unidirectional glass fibers in an epoxy matrix is 1950 kg/m3. If the densities of the glass and epoxy are known to be 2540 kg/m3 and 1300 kg/m3, calculate the weight fraction of fibers in the composite
[4 marks]Describe the analysis of continuous fiber composite having the longitudinal properties.
[7 marks]PEEK is to be reinforced with 30% by volume of unidirectional carbon fibers and the properties of the individual materials are given below. Calculate the density, modulus and strength of the composite in the fiber direction. Material Density Tensile Strength Modulus (kg/cm3) (GN/m2) (GN/m2) PEEK 1300 0.058 3.8 Carbon Fiber 1800 2.1 400
[3 marks]Aball-point pen made from polypropylene has the clip design shown in Figure. When the pen is inserted into a pocket, the clip is subjected to a deflection of mm at point A. If the limiting strain in the material is to be 0.5% calculate (i) a suitable thickness, d, for the clip (ii) the initial stress in the clip when it is first inserted into the pocket. The short term modulus of Polypropylene is 1.6 GN/m2.
[2 marks]Explain: Iso thermal flow in channels: Non Newtonian fluids -flow of power law fluid along a channel of uniform circular cross-section.2
