Theoretical problems concerning the determination of work parameters of the two-phase sand-air stream in the cores making process by blowing methods as well as experimental methods of determination of the main and auxiliary parameters of this process decisive on the cores quality assessed by the value and distribution of their apparent density are presented in the paper. In addition the results of visualisations of the core-box filling with the sand-air stream, from the blowing chamber, obtained by the process filming by means of the quick-action camera are presented in the paper and compared with the results of simulation calculations with the application of the ProCast software.
The effects of filling the core box cavity and sand compaction in processes of core production by blowing methods (blowing, shooting) depend on several main factors. The most important are: geometrical parameters of cavity and complexity of its shape, number, distribution and shape of blowing holes feeding sands as well as the venting of a technological cavity. Values of individual parameters are selected according to various criteria, but mostly they should be adjusted to properties of the applied core sand. Various methods developed by several researchers, including the authors own attempts, allow to assess core sands properties on the basis of special technological tests projecting the process into a laboratory scale. The developed criteria defining a degree or a filling ability factor provide a better possibility of assessing the core sand behavior during flowing and core box filling, which indicate the value and structure of the obtained compacting decisive – after hardening – for strength and permeability. The mentioned above aspects are analyzed – on the basis of authors’ own examinations - in the hereby paper.
The paper presents an estimation of liquefaction susceptibility of some soils from the coast of the Marmara Sea, which was heavily striken by the Kocaeli earthquake in 1999. Firstly, the results of field investigations are summarized. Then, the results of laboratory investigations of physical and mechanical properties of the soils collated from the sites investigated are presented. The mechanical properties relate to the compaction/liquefaction model of saturated soils. This model is briefly outlined, then respective experimental procedures dealing with its calibration described, and values of material parameters listed. Liquefaction potential of investigated soils is analysed using standard procedures, based on the grain size distribution curves and SPTs. Finally, the simulation of pore-pressure generation and onset of liquefaction of Turkish soils is carried out, using the compaction/liquefaction model. Discussion of some standard empirical procedures of estimation of liquefaction potential of saturated soils, conducted from the analytical point of view, is also presented.
The paper deals with experimental investigations of a set of metal "2-delta" gaskets of different depth. The gaskets were examined under assembly conditions, i.e. placed in their seats and loaded with the compressive assembly force with no operating pressure applied to the closure. The electric resistance wire strain gauges were used to measure the circumferential and axial strains at the inner cylindrical surface of the gaskets. The plastic deformations of the contact surface of the seats were measured after disassembly of the closures. The material tests were carried out to determine real mechanical properties of materials applied for the gaskets and the seats. The results of experiment were compared with the analytical approach. The plastic deformations were taken into account in the analytical solution of the contact region between the gasket and the seats. The results of experiment and analytical approach were verified by FEM calculations, which take into account linear hardening of the material, friction and contact effects.
The paper deals with experimental investigations of a set of metal wave-ring gaskets of different thickness and different assembly interference. The gaskets were examined under assembly conditions, i.e. pressed in their seats with no operating pressure applied. The electric resistance wire strain gauges were used to measure the circumferential and axial strains at the inner surface of the gaskets. The traces of contact at the working surface of the gaskets were measured after disassembly the gaskets from their seats. The material tests were carried out to determine the real mechanical properties of materials applied for the gaskets and the seats. The results of experiment were verified by FEM calculations and compared with the analytical approach based on the simplified shell model proposed for the gasket.