Influence of Fluid on Seal and Assembly of Pipeline Fittings Based on the Multiscale Finite Element Model

Pipeline fittings with ferrules are applied to connect sections of hydraulic pipelines in aircraft, and their reliability and stability are essential. This paper aims at investigating the influence of internal fluid on the sealing characteristics of pipeline fittings by employing the multiscale model. Changes in the sealing characteristics induced by the fluid pressure switch are studied, and the assembly method under the internal fluid is also explored. The calculated results show that the multiscale model can accurately reflect the changes in the sealing area, and the high-pressure fluid can enhance the sealing reliability. Compared with the contact area, the fluid pressure exerts a greater influence on the change in the area of the high-stress zone. Furthermore, the unrestored sealing area enlarges with the increased maximum fluid pressure, and the change in the area of the high-stress zone is significantly larger than that in the contact area. Moreover, the optimum assembly position of ferrule decreases with the increase in fluid pressure, thus achieving the excellent sealing characteristics.

Analytical and Finite Element Solution of Tractor Brake Link to Achieve Weight and Cost Reduction

In tractor brakes, when the brake is applied, tension in the operating rod causes the links to turn the two actuating disc slightly, in opposite directions. The shape of the recesses in which the hardened steel balls locate is such that, as disc move relative to each other, the ball force them apart and apply pressure to the rotating discs. The automotive industry has for many years identified weight reduction as a way of improving product competitiveness and thus the ability to make profits. In present work, an attempt has been made to reduce the thickness of link and hence achieve weight reduction and cost savings. The actuator link has been analyzed for stresses. The existing link is of 6 mm thickness and is made of C – 40 steel. The existing link of 6 mm thickness along with links of 5 mm and 4 mm thickness were considered for analysis. It is found that the stresses in 5 mm thick link are well within limits with a factor of safety of 2.3. This reduction in thickness would yield a reduction in weight of link and hence would reduce the cost of link with a saving potential of Rs.14, 40000/= per year considering the fact that 6, 00,000 tractors are sold in India every year. Experimental investigation showed the zone of failure of link is in line with the high stress zone indicated by finite element analysis.

Simulation of Influence of Friction Coefficient on Extrusion of TC4 Alloy

Based on Simufact11.0, a 3-D model of T profile extrusion is established and the extrusion process of TC4 is investigated using finite volumemethod(FVM) of Euler mesh description. Effects of different friction coefficients on the effective stress, extrusion pressure, effective strain and effective strain rate have been studied. The study shows that there is a high-stress zone at a certain distance from the entrance of the forming area and a high strain rate zone around that area. With the increase of friction coefficient, the value of the stress increased and the deformation is more uneven. The track of extrusion pressure shows that extrusion increase with the increase of friction coefficient.

Effects of Inoculation on Microstructures and Mechanical Properties of Resistance Spot Welded Magnesium Alloy Joints

Resistance spot welded magnesium alloy joints contain the nugget and heat affected zone (HAZ), and the weld nugget of magnesium alloy generally contains two different microstructures, the cellular dendritic crystals at the edge of the nugget and the equiaxed dendritic crystals in the center of the nugget. Characteristics of cellular dendritic crystals make the cellular dendritic crystals zone to be the weak area, and the more unfortunate thing is that it is located in the high-stress zone, which further degrades the mechanical properties of the joints. Based on this conditions, inoculation would be tried to refine the cellular dendritic crystals in order to improve the mechanical properties of resistance spot welded magnesium alloy joints. Al-10Sr was chosen as the inoculant in this experiment. As the addition of Al-10Sr increases from zero to 1.4mg, the average width of cellular dendritic crystal zone decreases from 332μm to 58μm while the microstructure tends to be refined, accordingly, tensile shear load of the joints increases by 24.3% from 2.379 KN to 2.959 KN. It is favorable to select a relative higher content of Al-10Sr addition to improve the mechanical properties of the spot welded magnesium alloy joints.

Deformation Mechanism of the Mountain and Research of Reinforcement in Yanchi Mountain

Mining activities would generate large scale goaf, and the existing of goaf makes the mountain body produce great distortion. Therefore, it has become a kind of serious geological hazard. Based on the concrete conditions of Yanchi Mountain, the simulation with ANSYS was conducted for analyzing the stability of goaf, mine pillar and roof, which would find out the high stress zone and plastic zone of the goaf. Therefore, the conclusion that inadequate of the pillar strength is the main cause of the mountain deformation is drawn, and a new strengthening method which is to strengthen the mine pillar and to increase new mine pillars is put forward on basis of the conclusion.The results show that the strengthening method has an obvious effect, and it reduces the workload and the cost, which also provides very significant evidence for the future studying.

Characters of Expressway Widened Engineering Reinforced with Geotextile

Based on nonlinear finite element method, the character of expressway widened engineering reinforced with geotextile is studied. It is found that the main vertical settlement, lateral displacement and failure surface of embankment occurred in the widened part of embankment. The lateral displacement decreased, the total incremental of displacement reduced and the stability of embankment enhanced when expressway widened engineering reinforced with geotextile. It also can be found that the axial force of geotextile get its maximal value at the intersection of old and new part of embankment, which is controlled by the differential settlement and normal stress mainly. In order to reinforce the embankment effectively, it is advised that the geotextile should be paved on high-stress zone.

Evaluation of Cracked Beam-to-Column Connection from Brittle Failure Using Finite Element Method

The bolted end-plate composite beam-CCSHRC column connection was validated to be ductile and offered an alternative to pre-Northridge connection. This study aims at the beam lower flange fracture in the connection test, and applies the J-integral criteria to examine the connection’s nonlinear fracture behavior. Advanced 3-D connection models containing initial crack in the high stress zone at lower flange are created, and the J values at the crack tip are calculated with considering the influences of certain parameters. The results demonstrate that the J values are strongly affected by the initial crack length and interstory drift. For 0.94, 1.35, 1.86 and 2.50 mm long crack, the J values sharply increase during loading history. The crack with a length of 2.50 mm propagates at a 66 mm drift, while the 1.35 mm long crack grows at a 120 mm drift. For 0.94 or 0.61 mm long crack, it keeps stable without growing upon loading. Besides, the J values exhibit a weak sensitivity to the beam concrete strength and tensile reinforcement ratio for beam. Under the same drift, the J-integral increases by about 3.5% when concrete strength changes from 15 to 24 MPa, and the J values at 0.6% tensile reinforcement ratio for beam are 1.5% larger than those at 0.3% or 1% reinforcement ratio.