The paper presents the full transient, two-dimensional finite volume method numerical calculations of the classical involute scroll compressor geometry. The purpose of the study was to develop and evaluate an adaptable implementation of numerical fluid mechanics and thermodynamics modeling procedure with a mesh deformation. The methodology consisting in the compression chamber geometry preparation, mesh generation and governing equations solving was described. The evaluation was carried by simulating an adiabatic compression process and the results were compared with the theoretical zero-dimensional model and the existing research concerning the scroll chamber computational fluid dynamics modeling. It has been shown that the proposed modeling routine results in good accuracy for the scroll compressors study applications.
Steel Mesh-Reinforced Cementitious Composites (SMRCC) (traditionally known as ferrocement) have been in existence for few decades, but have some limitations set on element thickness and number of reinforcing mesh layers and the resulting deflection ductility. Therefore, the author has made an attempt to explore whether deflection ductility will improve in mesh-reinforced cementitious composites (25 mm thick) if discontinuous fibres are added to slab elements. For this purpose, thin slab elements of dimensions 700 mm (length) × 200 mm (width) × 25 mm (thickness) were cast and subjected to four point bending tests. Based on the flexural tests conducted on SMRCC (Control Slab Elements, cast with Steel Mesh Volume of reinforcement, MVr = 0.78, 0.94, and 1.23%) and Hybrid Mesh-and-Fibre-Reinforced Cement Based Composite (HMFRCBC) (Test Slab Elements, combining MVr = 0.78, 0.94 and 1.23% and Polyolefin Fibre Volume fraction, PO-FVf = 0.5‒2.5% of volume of specimens, with 0.5% interval), load-deflection and the deflection ductility index were analyzed. From the flexural load-deflection curves it has been observed that HMFRCBC slabs demonstrate higher flexural load-carrying capacity and deflection ductility when compared to SMRCC slabs. This study shows that higher the polyolefin fibre volume fraction (PO-FVf) from 0.5 to 2.5% (with a 0.5% interval) in HMFRCBC slabs, the higher the flexural deflection ductility. The Deflection Ductility Index (DDI) of HMFRCBC (with 5 layers of mesh and PO-FVf = 2.5%) is 4.5 times that of SMRCC. This study recommends that HMFRCBC can be used as an innovative construction material due to its higher flexural ductility characteristics.
This study aims to evaluate the efficiency of strengthening reinforced concrete beams using some valid strengthening materials and techniques. Using concrete layer, reinforced concrete layer and steel plates are investigated in this research. Experiments on strengthening beam samples of dimensions 100x150x1100 mm are performed. Samples are divided in to three groups. Group “A” is strengthened using 2 cm thickness concrete layer only (two types). Group “B” is strengthened using 2 cm thickness concrete layer reinforced with meshes (steel and plastic). Group “C” is strengthened using steel plates. The initial cracking load, ultimate load and crack pattern of tested beams are illustrated. The experimental results show that for group A and B, the ultimate strength, stiffness, ductility, and failure mode of RC beams, with the same thickness strengthening layer applied, will be affected by the mesh type, type of concrete layer. While for group C, these parameters affected by the fixation technique and adhesion type.
Th is report provides a concise overview of the rendering and utilization of three-dimensional models in the fi eld of anatomy. Anatomical three-dimensional virtual models are widely used for educational purposes, preoperative planning, and surgical simulations because they simply allow for interactive three-dimensional navigation across the human organs or entire body. Virtual threedimensional models have been recently fabricated as accurate replicas of the anatomical structures thanks to advances in rapid prototyping technology.
The paper presents an approach of numerical modelling of alloy solidification in permanent mold and transient heat transport between the casting and the mold in two-dimensional space. The gap of time-dependent width called "air gap", filled with heat conducting gaseous medium is included in the model. The coefficient of thermal conductivity of the gas filling the space between the casting and the mold is small enough to introduce significant thermal resistance into the heat transport process. The mathematical model of heat transport is based on the partial differential equation of heat conduction written independently for the solidifying region and the mold. Appropriate solidification model based on the latent heat of solidification is also included in the mathematical description. These equations are supplemented by appropriate initial and boundary conditions. The formation process of air gap depends on the thermal deformations of the mold and the casting. The numerical model is based on the finite element method (FEM) with independent spatial discretization of interacting regions. It results in multi-mesh problem because the considered regions are disconnected.
We apply a fluid-structure interaction method to simulate prototypical dynamics of the aortic heart-valve. Our method of choice is based on a monolithic coupling scheme for fluid-structure interactions in which the fluid equations are rewritten in the 'arbitrary Lagrangian Eulerian' (ALE) framework. To prevent the backflow of structure waves because of their hyperbolic nature, a damped structure equation is solved on an artificial layer that is used to prolongate the computational domain. The increased computational cost in the presence of the artificial layer is resolved by using local mesh adaption. In particular, heuristic mesh refinement techniques are compared to rigorous goal-oriented mesh adaption with the dual weighted residual (DWR) method. A version of this method is developed for stationary settings. For the nonstationary test cases the indicators are obtained by a heuristic error estimator, which has a good performance for the measurement of wall stresses. The results for prototypical problems demonstrate that heart-valve dynamics can be treated with our proposed concepts and that the DWR method performs best with respect to a certain target functional.