Papers by Keyword: Perforation

Abstract: This study aims to experimentally analyze the performance of a forced wet cooling tower (WCT) using a multi-level inclined perforated splash fill. The hot water temperature adjusts to 60 °C; Packing has inclination angles of 15^o, 20^o, 25^o and a perforation ratio of 2.6%, consisting of five levels of galvanized plate fill. Water flow rate ± 0.0917 kg/s, five variations of air flow rate are 0.02033, 0.02631, 0.02995, 0.03770, and 0.04261 kg/s. The inlet hot water temperature is 60 °C. In this study, the best WCT performance occurred at an inclination angle of 15^o.

Abstract: In designing materials to resist impact and penetrations, numerical simulation offers effective means to ascertain impact mechanism close to practical experimental procedures. This work presents penetration characteristics of water as an inter-layer between ultra-high strength steel sandwich structure. Residual velocities for both monolithic and sandwiched structures have been investigated. In the case of the monolithic structure, good agreement was found between experimental and simulation results in reducing projectile initial velocity of 854 m/s to obtained residual velocities of 487 m/s and 460 m/s respectively. Energy dissipation capability of water as an interlayer has also been investigated. Water, proving very effective in decreasing projectile velocity of 390 m/s to zero in a 2 mm steel-2 mm water – 2 mm steel sandwich system. Numerical simulation has been carried out using Ansys Explicit / Autodyn – a commercial software based on finite element method which is very effective in solving non-linear problems. Lagrange elements were used in the discretization of both the water and steel media.

Abstract: The leakage accident of corrosion perforation occurred in the L245 oil pipeline. After pipe replacement,the defects were analyzed by means of macro analysis, corrosion product analysis, medium composition analysis, chemical composition analysis, mechanical property test and SEM. The results showed that the corrosion perforation was caused by local corrosion, and the synergistic effect of HCO₃^- and Cl^- in transportation medium was the main cause of local corrosion.

Abstract: The purpose of this paper is to study the ballistic perforation resistance of double-layered steel plates subjected to impact by conical projectiles with different nose angles. Based on nonlinear finite element theory, different rigid projectiles vertically penetrating into double-layered Weldox 460E steel plates are simulated with LS-DYNA code. The configurations in the penetration process and failure modes of steel plates are given. The results of monolithic and layered targets are studied and compared for projectiles with different nose angles. It is revealed that compared to the monolithic plate, the double layer configuration is able to improve the ballistic limit for the target under impact by blunt-nose projectiles, and for sharp-nose projectiles the double layer configuration obviously weakens the ballistic resistance.

Abstract: Nowadays, the welding quality of circumferntial welds is the main influencing factor of the service behaviors of long-distance transport pipeline, and the accidents caused by the circumferential welding defects have get extensive attention. To figure out the leaking reason of circumferential weld of the steel 20 buried pipeline, with macro inspection, nondestructive testing, physical and chemical properties, methods of medium leakage and fracture analysis, we found that the welding defects in the weld toe are mainly responsible for pipeline leaking. The welding defects of circumferential weld destroy the continuity of welding, which result in the stress concentration and cracks. Under the combined action of corrosion, erosion, working stress and welding residual stress, the cracks extend along the welding weak areas and penetrates the welding metal, finally leading to the leakage failure of the welds, also some suggestions are given to prevent similar accidents.

Abstract: For unconventional oil and gas well perforating technology, field complex fracturing process to carry out the casing perforation physical simulation test, determine the different perforating process corresponding to the aperture size morphology, based on this, according to the physical simulation test results, perforating casing finite element model is established, the analysis of stress concentration around the perforation under different construction conditions, determine the outer extrusion safety factor, for complex oil and gas field casing string design and provide technical support. Keywords: complex fracturing;perforation; casing; mechanical properties

Abstract: Using classical explicit nonlinear dynamic analysis software of ANSYS/LS-DYNA, this paper analyzes the process of perforating jet penetrating on four types of concrete target with unconfined compressive strength of 30 MPa, 50 MPa, 30 MPa & 50 MPa and 50 MPa & 30 MPa. The result shows that penetration of shaped charge will decrease if cross-formation perforation occurs and in order to guarantee the penetration performance during perforating, perforating should be parallel to the direction of oil formation and be avoided from working on high-strength tight formation and up-and-down cap-rock.

Abstract: This paper presents the results of an experimental investigation of the impact resistance of UHPFRC slabs. The influence of horizontal and vertical casting of thin slabs against penetration by a projectile is described. The resistance of penetration by a projectile was investigated using projectile with lead core. The results indicate different penetration depths and crater diameters in the target specimens for both kind of casting. Which points on a different arrangement of fibers for horizontal and vertical casting slabs. However, the protective ability is guaranteed in both placement method. Based on the present findings the slabs from ultra-high performance fiber-reinforced concrete casted vertically appear to be most efficient in protection against projectile impact.

Abstract: Experiments and simulations on projectile impact to circular and rectangular plates made of aluminum alloy 2024-T3 were carried out. Ballistic limit and deformation of circular plates and rectangular plates at impact point were examined. The experimental results were compared with the simulation ones which calculated using the materials properties experimentally obtained. The effects of mesh size and fracture strain on both the crack limit velocity and the perforate limit velocity were discussed.

Abstract: This paper presents a numerical investigation on the effect of perforation to the steel purlin on bending behaviour. In order to reduce the weight of steel sections, web profile with openings has been introduced in the construction industry, so does the purlin. However, there is no research done on the C-purlin with perforation. Hence, 33 nonlinear analyses were carried out to investigate effect of perforations to the steel purlin on bending behaviour. Yield moment of the steel purlin with and without perforation will be determined. And, effect of various perforation shapes and size on bending behaviour is investigated. Finite element model was developed using software LUSAS. C-channel steel section without opening is used as a control specimen. The results are expressed in term of yield moment. The results show that the edge distance from the opening to the support plays an important role in affecting the moment capacity of C-purlin. Increasing the opening spacing would increase the moment capacity. Number of openings also affects the moment capacity of the section. Octagonal shape with 0.40H and e= 350 mm shows the highest yield moment value with 16.318% higher than that of section without opening. In conclusion, perforation increases the moment capacity of the C-steel purlin.