Papers by Keyword: Shell

Abstract: The paper shows a conclusion and a solution of principal resolving equations of the motion of linear and geometrically non-linear theories of thin depressed shells with median surface breaks. A formula has been obtained for determining the shell’s free bending harmonic oscillation frequency in case of a hinge support on rigid diaphragms. Charts are supplied showing the dependence of free oscillation frequency on the change of different factors. A conclusion has been drawn concerning the analytical method efficiency.

Abstract: The effect of the volumetric flow rate on the heat transfer of shell and tube heat exchangers was investigated. Furthermore, a comparison of four flow models using for numerical simulation was discussed to provide improved predictions of turbulent flow in the shell and tube heat exchangers. Four flow models tested were Reynolds stress model, k-ε Standard model, k-ε RNG model and k-ε Realizable model, respectively. Multi reference frame technique was used with Fluent software package. During the numerical simulation, the heat dissipation was shown to be strongly dependent on the choice of turbulence model. Compared with the cold model experimental result, k-ε RNG model was a better turbulence model for the prediction of the heat dissipation in the shell and tube heat exchangers among the four models. Furthermore, the good agreement between the numerical results and the experimental result confirmed the validity of the numerical method.

Abstract: Steinberg failure models based on Mott distribution in ANSYS/LS-DYNA was used on the formation of fragments.The forming process of the fragment damage field of the shell was simulated. The mass distribution、spatial distribution and the attenuation law of initial velocity of fragments are analyzed. The shell damage-field may serve as a basis for the future research on power of shell fragment to the targets.

Abstract: This article focuses on the analysis of stresses within a thin-walled vessel. Focused on rotary symmetrical shell, boundary faults arising at the junction of the cylindrical part of the vessel and its bottom are monitored. The bottom of the vessel is designed in three variants and obtained values of stresses are compared. From the obtained results it is possible to assess which form of the bottom is preferred.

Abstract: In this paper, the simplified approach using commercial computer software code was adopted to predict the performance of a kettle typed shell and tube heat exchanger. Similarly the numerical analysis using ANSYS/CFX is conducted for the same design and the result data are collected to analyze its performance numerically. In general, the heat exchanger performances are evaluated by predicting the temperature difference and pressure drop. The result data of both the analysis are compared to find the differences between the data. From the comparison, we came to know that the error percentage between the two analysis results is very low which is acceptable proving our design is convincible. Thereby we fabricated a prototype model of shell and tube heat exchanger (kettle type) with the same parameters used for these analyses.

Abstract: Due to the corrosion of liquid and dual role of job stress, the pump housing of the LH45 type three cylinder high pressure plunger pump was caused the breakage in the practical work, and its service life was greatly reduced. Studied the pump housing broken state and laws to selected material to manufacture. Established 3D entity of the pump housing model in the 3D CAD software so that the stress and strain state of remade shell can be analyzed using finite element software ANSYS. Compared with the state of stress and strain before shell remaking, the pump housing remaking is proved to be valid.

Abstract: In this paper, the shell’s strength and stiffness is calculated according to the theory of elastic mechanics and elastic-plastic mechanics theory.And the analysis of the ANSYS software verify the reliability of the theoretical calculation . Using ANSYS parameter design language (APDL) and the optimized design module of ANSYS,the author studies Material nonlinear static analysis ,and establish the parametric analysis program.

Abstract: Two sets of new and in-service helmets were impact tested using a drop test machine, in accordance to established helmet test protocols. The first test for full helmets was executed in compliance with standard speed requirements of 5.9 m/s in which three of five new helmets performed poorly. The second set utilized lower impact speed of 4 m/s for individual helmet components test. New helmet liners absorbed 5 times more impact energy than the in-service liners while the new shell was 19.3% better in dispersing impact energy than the in-service shell. The undesirable changes in liner thickness have explicit effect on the liner density which is translated into reduction in energy absorbing potential. In brief, exposure to weathering stresses and use intensities has affected helmet impact performance, regardless of service duration.

Abstract: In Nature, calcium carbonate biomineralizations are the most abundant mineralized structures of biological origin. Because many exhibit remarkable characteristics, several attempts have been made to use them as substitution materials for bone reconstruction or as models for generating biomimetic composites that exhibit tailored properties. CaCO₃ biomineralizations contain small amounts of amalgamate of proteins and polysaccharides that are secreted during the calcification process. They contribute to control the morphology of the crystallites and to spatially organize them in well-defined microstructures. These macromolecules, collectively defined as the skeletal matrix, have been the focus of a large number of studies aiming at synthesizing in vitro biomimetic materials, according to a bottom-up approach. However, recent proteomic investigations performed on the organic matrices associated to mollusc shells or to coral skeletons have quashed our hopes to generate, with only few macromolecular ingredients, biomimetic materials with properties approaching to those of natural biominerals. As a mean value, each matrix comprises a minimum of few tens of different proteins that seem to be strictly associated to calcium carbonate biominerals. Among the proteins that are currently detected, one finds RLCDs-containing proteins (Repetitive-Low-Complexity Domains), enzymes, proteins with protease inhibitors domains and at last, proteins that contains typical ECM (ExtraCellular Matrix) domains. Today, we still do not understand how the skeletal matrix works, and unveiling its complex functioning is one of the challenges for the coming decade, both from fundamental and applied viewpoints. Is it realistic to attempt generating abiotically, in a test tube at room temperature, biomimetic composites that mimic natural biomineralizations in their properties If so, and by supposing that we know the individual functions of all the components of the matrix, is there a minimal number of proteins required for producing in vitro calcium carbonate biomaterials that approximate natural biominerals These issues are of importance for the future research directions in biomaterials science.

Abstract: In order to make the shell production automatically and efficiently, reduce the injury to the worker’s health caused by the harmful dust, this paper describes an automatic shell production line controlled by PC and PLC. The executive body of the shell production line is robots, PLC transmits signals between robot and PC. The new automatic shell production line can not only stucco but also possess the features of smooth operation for shell making and reliable use and low noise. It has been proved that the shells automatic production line has improved production efficiency, reduce the contact with harmful environment of manipulators greatly, and make the production process are controlled well and safely.