Maximum Amount Of Deformation Research Articles

Water hammer stress on water transmission line

ABSTRACT The present work investigated the pressure changes caused by water hammer through the georeferenced model to investigate the stress impact on water transmission lines. The results of the hydraulic analysis of the research showed that the sudden stop of the pumps in the transmission line 1,600 m in length caused negative pressures of −5 to −10 (bar). In pressure values close to −10 (bar), the water vaporization, cavitation, and separation of the column happened. The maximum pressure in the transmission line was calculated to be 43 (mH2O) and the minimum pressure in the transmission line was 10 (mH2O). The relative vacuum mentioned in the transmission line as a destructive factor caused two columns of steam and water to collide. The collision of two columns caused a great pressure that had the potential to destroy the transmission line. The research results showed that the maximum amount of elastic strain was equal to 16772E-7 mm/m. The equivalent stress beneath the pipe Q4 varied from 0.000 to 7E-2 m and the maximum stress value was 3.3535E7 (Pascal). The maximum amount of deformation or change in the shape and size of the pipe due to the applied stress (0.000–7E-2 m) was equivalent to 1.9287E5 m.

Hot Deformation Behavior and Processing Maps of 26CrMo7S Steel Used in Oil Exploration.

The hot deformation behavior and flow stress characteristics of experimental 26CrMo7S steel were analyzed using a thermal simulator under a range of conditions, including a strain rate range of 0.01~10 s-1, a temperature range of 850~1250 °C, and a maximum deformation amount of 70%. The Arrhenius constitutive model was built for the corresponding conditions, and the model's accuracy was verified through error analysis. Additionally, hot processing maps were constructed to analyze the processing zone of the steel under different hot deformation conditions. Finally, the microstructure of the processing zones was observed and verified using the electron backscattered diffraction (EBSD). The results indicate that the interaction of work hardening and dynamic softening influences the hot deformation behavior of 26CrMo7S steel. The Arrhenius constitutive equation with a value of the correlation coefficient (r = 0.99523) accurately predicts the flow behavior of 26CrMo7S steel under different strains. The optimal processing zone obtained with the hot processing maps is within a deformation range of 1010~1190 °C and a strain rate range of 0.01~10-1.5 s-1, and the obtained microstructure is in good agreement with the analysis results.

Investigation on the performance of a helico-axial multiphase pump under slug flow

The helico-axial multiphase pump is often used for gas-liquid mixture transportation in offshore oilfields, and slug flow is the main reason for the unstable operation of the pump. Aimed for slug flow condition, a self-designed three-stage multiphase pump is set to the object to perform unsteady simulations and fluid-structure interaction calculations, and the inlet gas void fraction (IGVF) is set from 20% to 80%. The results show that affected by the flow from the slug, the gas-liquid two-phase flow pattern in the multiphase pump changes sharply, resulting in severe fluctuations in the differential pressure, spindle torque and deformation of the multiphase pump. The gas-phase enters the first-impeller along the suction blade surface when affected by Taylor bubbles, while the second and third-stage impellers gas-phases are in the form of small air masses flow into the impeller along the pressure blade surface. The deformation trend of impeller torque, differential pressure and the main pump spindle is similar to that of trigonometric function, while the fluctuation of torque is more intense, and the shape variable of spindle increases with the inflow of liquid plug, and the maximum deformation amount increases by 10.9% at high GVF relative to IGVF.

Study on the Loess Immersion Test of Metro Line 2 in Xi’an, Shaanxi Province, China

With the implementation of China’s western development and “One Belt, One Road” initiative, there are more and more projects in the collapsibility loess area, and the collapsibility loess problem encountered in the construction is becoming more and more prominent. In this paper, the collapsibility loess of the south extension section of Xi’an Metro Line 2 is investigated, and its collapsibility characteristics are studied through a large-scale site immersion test. The test site was a 15 m diameter circular test pit, which took 35 days for water injection and 60 days for observation after water stopped. The test results showed that the maximum self-weight collapsibility of the soil layer in the test pit is 32 mm, and the deformation amount is 10.05 mm in Q3 and 9.55 mm in Q2. The maximum deformation amount of 32 mm is less than 70 mm in the shallow marker; it may be caused by the paleosol layer as a bridge to provide a support to the overlying soil layer. The shape of the sphere of influence after immersion resembles a trumpet, slightly protruding outwards from the paleosol. The scope of influence between the infiltrated and saturated zones gradually increases with depth, and the saturated zone is generally smaller than the infiltrated zone. The research results of this paper can provide technical support and reference for the construction of Xi’an Metro Line 2 and other related projects in the region.

Parametric Design on Solving the Maximum Deformation of Traction Helical Gear on Locomotive

The helical gear for locomotive traction has a popular application in the locomotive transmission system due to its excellent transmission performance. The maximum amount of deformation needs to be taken into consideration when performing the tooth profile modification on helical gear. The tooth profile design and corresponding calculation process tend to be tedious since the variation of the contact ratio of gear might lead to the change of logarithm in meshing tooth. In this paper, starting from the effect of the contact ratio on the logarithm of meshing teeth, the mesh-stiffness of helical gear can be solved by cross-section deformation formula based on the similarity of helical gear and spur gear. And then the general calculation formula governing the variation on the length of contact line is derived regarding the moment when gear tooth just engages. On the basis of actual production requirements, the solution equation for inter-tooth load distribution coefficient is derived. As a result, the general mathematical model for maximum deformation of helical gear which can perform parameterized calculation is established. The theory provides a significant theoretical guide in the field of tooth profile modification on locomotive traction helical gear.

Research on the Pump Shaft Stability Analysis of Multistage Centrifugal Pump During Closed-Valve Start-Up Process

In order to analyze the pump shaft stability of multistage centrifugal pump during the closed-valve start-up process, the transient internal fluid field and structural field during the closed-valve start-up process of the TDM 35-140×13 segmental multistage centrifugal pump are solved by transient fluid-solid coupling. The transient deformation and vibration velocity of the pump shaft are analyzed. It is found that the maximum deformation amount of the third stage impeller and the pump shaft cylindrical contact surface (N=7 node area) during the whole closed-valve transition start-up process is the largest. The maximum deformation in the region where the nodes 1≤N≤10 are significantly greater than that in other regions. In the 11≤N≤19 node, with the node position coordinate value N increasing, the maximum deformation amount is continuously decreasing. During the entire closed-valve transition start-up process, the vibration speed of the pump shaft fluctuates drastically. In the node of 1≤N≤19, with the node position coordinate value N increasing, the maximum vibration velocity first increases and then decreases. The maximum vibration speed at N=11 nodes is higher than that of all other nodes.

Deformation properties of coarse-grained sulfate saline soil under the freeze-thaw-precipitation cycle

Salt expansion deformation is the main engineering hazard of saline soil, which restricts the application of coarse-grained sulfate or sulfite soil as roadbed filling. The main factors affecting salt expansion deformation are change of salt, water and temperature. The principal research objectives of this paper is to offer a basic data reference for the structural design of coarse-grained sulfate saline soil roadbed. To investigate the deformation properties of coarse-grained sulfate saline soil under the freeze-thaw-precipitation cycles, the large-scale sample experiments under the freeze-thaw-precipitation cycles and the freeze-thaw cycles were carried out with self-designed experiment equipment. The results showed that under the same freeze-thaw-precipitation cycles experiment conditions, the minimum temperatures of these samples with 1.5% and 3.0% soluble salt contents at a depth of 20 cm were 3.32 °C and 3.56 °C, respectively. In addition, it took less time for the lower salt content (1.5%) sample to reach the same low temperature compared to the higher salt content sample (3.0%). However, after seven freeze-thaw-precipitation cycles, it was shown that deformation of the sample with 1.5% soluble salt content was 32% higher than that with 3.0% soluble salt content. The maximum deformation amount of the coarse-grained sulfate saline soil after repeated freeze-thaw-precipitation cycles experiment was approximately 1.9–9.4 times larger than that after repeated freeze-thaw cycles experiment, which indicated that precipitation had a serious impact on the deformation of the sample. However, there was almost no difference between the lower salt content and higher salt content samples in the residual deformation caused by the cumulative effect of salt expansion in each cycle. Furthermore, the results showed that under the influence of precipitation, a high-level soluble salt content did not necessarily promote expansion deformation of coarse-grained sulfate soil. Water, salt, and temperature have complex coupling effects.

Mine Pressure Behavior Characteristics and Control Methods of a Reused Entry that Was Formed by Roof Cutting: A Case Study

Noncoal pillar mining with automatic formation of a roadway is a new coal mining method that is tailored to improve the coal resource recovery rate and reduce the investment in roadway tunneling. Using this proposed method, a reuse entry is formed by roof cutting instead of tunneling. In this paper, the S1201-II working face of the Ningtiaota Coal Mine was used as a case study. The stress distribution of surrounding rock and the roof deformation characteristics of the reused entry during the mining process of the second working face were studied through FLAC3D numerical simulations combined with field measurements. The results indicate that the zone close to the reused entry led to higher stress in advance. If this stress is superimposed with the lateral pressure of the adjacent mined working face, it will be more difficult to maintain the reused entry. In the engineering case study described here, the reused entry created a stress increase zone and a severe deformation zone in the range of 0–80 m in front of the working face, and its range was approximately 37.5% larger than an ordinary entry. The stress peak in the stress increase zone increased by approximately 34.7% over that of an ordinary entry. The maximum amount of deformation within the severe deformation zone increased by 94.4% over that of an ordinary entry. To properly control the surrounding rock stress and deformation of the reused entry, a dynamic pressure bearing support in front of the working face with adaptability to the large roof deformation and high support strength is proposed here. Field application results showed that the final roof deformation with the dynamic pressure bearing support can be satisfactorily controlled within 110∼130 mm. These findings can provide a reference for researchers and field engineering technicians when engaging in the support work of reused entry.

Construction and analysis of puncture clamp model for 10KV insulation line based on finite element

At present, the puncture clamp has been widely used in the cable branching technology. However, due to the complicated installation process, the clamping force is too large during installation, resulting in cable damage and reduced life. If the clamping force is too small, it may cause poor contact or even cause fire. In this paper, the 3D solid model of the puncture clamp is established by using SolidWorks 3D software. Then the finite element analysis model of the puncture clamp is established in the finite element analysis software ANSYS Workbench, and the static analysis and exploration of the puncture clamp are obtained. The results show that the puncture blade and the conductor on the puncture clamp have the greatest contact stress and the maximum amount of deformation of the bolt, while the bolt meets the required strength. The results can be used to further optimize the structural design of the puncture clamps, refine the installation specifications and guide the installation.

Influence of Process Variables on the Stamping Formability of Aluminum Wing Nose Rib

Ribs are the forming components of the framework of an airplane wing. The nose ribs studied have a U-shaped geometry that consisted of a flat plate, a curved flange with various radius of curvature, and straight flange, and were produced by a stamping process. During stamping, some defects such as thinning, thickening, wrinkling, and springback may occur. To design a forming tool that produces good quality, it was essential to understand the influence of process variables. This study evaluated the influence of stamping process variables on the formability of the nose rib for prevention of excessive thinning and control of the springback phenomenon. Three important process variables namely, blank holder gap, die corner radius, and clearance between the die and the punch were analyzed during an Al-2024-O nose rib stamping. The stamping simulation was a nonlinear problem in nonlinear behavior of solid materials and contacts, which was applied to an elastic–plastic material employed with contact behavior conditions. A DOE design matrix was generated by a full factorial design with every combination of the design variables. The main process variables affecting the multi-objective function, i.e., thickness reduction ratio and springback amount were suggested through main effect analysis, along with the stamping simulation. An experiment was performed to verify the validity of the simulation results. Results indicated that the thickness reduction rate and the springback amount predicted by the simulation were in good agreement with the experimental results. The locations where the maximum thickness reduction occurred, the maximum deformation amount caused by springback, the blank holder force, and the initial blank shape were suggested in this paper. The influence of the process variables will be considered as a reference for improving the quality of the nose rib.

Settlement Evaluation of a Concrete Face Rock-Fill Dam (CFRD) Using a Back-Analysis Method Based on Measurement Results (A Case Study of Siah-Bisheh Dam)

The behavior of the Siah-Bisheh concrete face rock-fill dam in Mazandaran, Iran was investigated. Numerical analyses were performed before construction to evaluate the stability and predict the deformation of the dam. The material properties were chosen based on the results of geotechnical investigations. The amounts for deformation and settlement of the concrete surface were also calculated with the numerical model. The information from a number of geotechnical instruments was collected after construction and analyzed to measure settlement at different sections of the dam. The locations of the different deformations and their values are presented with various contours. The data were analyzed and used to revise the original numerical model of the dam. Following that, the long-term stability of the dam was evaluated, using parameters that were modified based on the measurement data. A comparison of the results from the numerical analysis and the values obtained from the dam settlement measurement showed that the initial results from the numerical model were much higher than the real values. It also showed that the number of construction layers used in the modeling of the dam had a significant effect on the obtained maximum amount of deformation.

Detection of high and moderate crustal strain zones in Uttarakhand Himalaya, India

We present geodetically estimated crustal strain rates in Uttarakhand Himalaya, a region which has long been considered as a part of seismic gap. We processed and analyzed the GPS data, acquired from the sites enveloping all the litho-tectonic units from the Sub Himalaya in the south to the Tethys Himalaya in the north together with the major Himalayan thrust/fault systems. On the basis of the obtained dataset, we conclude that the maximum amount of crustal shortening takes place towards the hinterland in the vicinity of Main Central Thrust and Inner Lesser Himalaya which is also in agreement with high seismic activity in these sectors. The GPS velocities of the sites (Indian reference frame) show significant variation from the sub-Himalaya to the Tethys Himalaya. The Sub and Inner Lesser Himalayan parts exhibit low deformation rate in contrast to the maximum amount of deformation in the Inner Lesser and Higher Himalayan segments. The strain analysis reveals lateral variation with high strain zones (HSZ) and moderate strain zones (MSZ) within the compressional regime in the Uttarakhand Himalaya. The strain rate of 0.45 and 0.25 micro-strain/year is observed in the HSZ and MSZ respectively. By comparing the strain rate with the seismicity pattern for the past five decades, we suggest that the earthquakes in the HSZ are related with ramp structure of the MHT, whereas, part of accumulated strain in the MSZ is being released in form of the present day seismic activity.

Failure mechanisms of soft rock roadways in steeply inclined layered rock formations

ABSTRACTIn recent years, with the increasing depth of coal mining around the world, traditional shallow geology mechanics are no longer suitable for the research on deep geological problems. In terms of deep mining, soft rock roadways in inclined rock formations show different deformation types compared with soft rock roadways in shallow horizontal strata. Based on the –1000 m track contact roadway in Qishan Mine of Xuzhou, physical model tests on the failure process of 45° and 60° inclined layered soft rock formations are carried out using physical models. The real-time monitoring of strain inside the model during the failure of soft rock formation is conducted to explore the failure mechanisms of 45° and 60° inclined layered soft rock formations in terms of in-depth high self-weight stress and horizontal tectonic stress. FLAC3D is also used for numerical simulation and comparative analysis. The roof and floor of the tunnels through 45° and 60° inclined formations fail on the left, and left and right walls fail near the bottom. The maximum displacement of the roof and floor of the 60° inclined formation is larger than that of the 45° inclined formation, and the maximum amount of deformation of left and right walls of the 45° inclined formation is larger than that of the 60° inclined formation, indicating failure features of different steeply inclined layered soft rocks roadways under high lithostatic stress and horizontal tectonic stress can provide a theoretical basis for mining and support of deep roadways.

Reversible and Nonvolatile Modulations of Magnetization Switching Characteristic and Domain Configuration in L10-FePt Films via Nonelectrically Controlled Strain Engineering.

Reversible and nonvolatile modulation of magnetization switching characteristic in ferromagnetic materials is crucial in developing spintronic devices with low power consumption. It is recently discovered that strain engineering can be an active and effective approach in tuning the magnetic/transport properties of thin films. The primary method in strain modulation is via the converse piezoelectric effect of ferroelectrics, which is usually volatile due to the reliance of the required electric field. Also the maximum amount of deformation in ferroelectrics is usually limited to be less than 1%, and the corresponding magnetoelastic strain energy introduced to ferromagnetic films is on the order of 10(4) J/m(3), not enough to overcome magnetocrystalline anisotropy energy (Ku) in many materials. Different from using conventional strain inducing substrates, this paper reports on the significantly large, reversible, and nonvolatile lattice strain in the L10-FePt films (up to 2.18%) using nonelectrically controlled shape memory alloy substrates. Introduced lattice strain can be large enough to effectively affect domain structure and magnetic reversal in FePt. A noticeable decrease of coercivity field by 80% is observed. Moreover, the coercivity field tunability using such substrates is nonvolatile at room temperature and is also reversible due to the characteristics of the shape memory effect. This finding provides an efficient avenue for developing strain assisted spintronic devices such as logic memory device, magnetoresistive random-access memory, and memristor.

Structural analysis on variable characteristics of automotive seat frame by FEA

In this study, structural analysis for the seat frame of automotive was carried out using finite-element analysis (FEA) technique and comparative analysis of the designs of lightening method, while not degrading the strength and stability of the frame. Maximum equivalent stress and maximum deformation amount on the whole seat frame were analyzed by employing the loading condition of passengers on the back and cushion frames, which were made of steel as in the current seat frame of automotive. Moreover, an additional structural analysis of a seat frame that is made of carbon fiber reinforced plastic (CFRP), instead of the currently using steel material, was performed. The result of this analysis showed that the maximum displacement is increased when using CFRP, instead of steel. In addition, the lower density property of CFRP materials has the potential to reduce the weight of the frame when compared with that of the steel material. Therefore, this result suggests that the steel material that is being currently used in most automotive must be reduced. Overall, this study identifies the structural safety of the seat frame of automotive by comparing the distributed strength of different materials.

Design of continuous circulation sub for gas drilling and the mechanical analysis on the sub body

Gas drilling, as an important part of underbalanced drilling, can increase drilling speed. But in the process of conventional gas drilling, it tends to cause cutting settlement, borehole collapse, sticking and other safety hazards because gas circulation has to be interrupted. Therefore, this paper presents a continuous circulation sub which can be installed and removed easily. With this sub, gas circulation will not be interrupted when drilling tools are connected and removed. This sub is composed of body, main valve, bypass valve and side entry sub. The structure design of its key components (i.e. main and bypass valves) were fulfilled. Based on statics analysis on the sub body, its force situations under extension, torsion and internal pressure were simulated by using the ANSYS finite element analysis software. It is shown that its stress distribution trend is consistent with its elastic–plastic mechanics analysis results. Stress concentrates around the two round holes of the sub body, and the maximum deformation amount is still at the stage of elastic deformation. The analysis results are in line with the elastic–plastic mechanics analysis results, and the requirement of body strength is satisfied. This paper provides a new program to guarantee the drilling safety of extended-reach wells, underbalanced wells and narrow-density window wells.

Worm Shaving Cutter Tooth Stress and Deformation Analysis

This paper discusses a new type of worm gear shaver shaving cutter tooth contact point during deformation force, and the establishment of the shaving force model, through the instantaneous cutting force to analyze the force deformation cutter shaving cutter tooth and precision of impact. And making use of a simplified model for variable cross-section cantilever, analyzing of tooth stiffness at any cross section, find the maximum amount of deformation of worm gear shaving cutters do theoretical foundation structure optimization.

An experimental investigation on hydrodynamics of charged water droplets in dielectric liquid medium in the presence of electric field

An experimental study was carried out to investigate the motion, deformation and breakup of charged water droplets in the presence of electric field. A typical nozzle-ring electrode apparatus was conducted consisting of a nozzle employed as high voltage electrode and a metal ring as grounded electrode. Experiments were performed in silicone 100cSt oil as an insulating medium. Under influence of D.C. electric field the motion and deformation of conducting water droplet and its detachment from the tip of nozzle were experimentally studied. The droplet behavior was recorded by high speed camera precisely and its responses to deformation influenced by electric field were digitally extracted by image processing of the sequential frames. Three parameters were defined in order to characterize the detachment of drop from nozzle and its deformation result from electric and hydrodynamic forces. Results show that increase in applied voltage leads to an increase in frequency of drop formation and subsequently droplet size declining. Moreover the motion of produced drops occurs in particular branches for voltages more than 3.5kV. The number of these branches increases with applied voltage. The maximum amount of deformation increases in higher voltages leading to drop break-up in 4.5 and 5.5kV applied voltages. The results can be helpful for better understanding of the phenomena taking place during droplet detachment in dripping mode and reveal the drop behavior (e.g. deformation) in electrospraying apparatus geometry which has not been studied before.

Parametric Finite Element Analysis of Physical Stimuli Resulting From Mechanical Stimulation of Tissue Engineered Cartilage

While mechanical stimulation of cells seeded within scaffolds is widely thought to be beneficial, the amount of benefit observed is highly variable between experimental systems. Although studies have investigated specific experimental loading protocols thought to be advantageous for cartilage growth, less is known about the physical stimuli (e.g., pressures, velocities, and local strains) cells experience during these experiments. This study used results of a literature survey, which looked for patterns in the efficacy of mechanical stimulation of chondrocyte seeded scaffolds, to inform the modeling of spatial patterns of physical stimuli present in mechanically stimulated constructs. The literature survey revealed a large variation in conditions used in mechanical loading studies, with a peak to peak strain of 10% (i.e., the maximum amount of deformation experienced by the scaffold) at 1 Hz on agarose scaffolds being the most frequently studied parameters and scaffold. This loading frequency was then used as the basis for simulation in the finite element analyses. 2D axisymmetric finite element models of 2x4 mm2 scaffolds with 360 modulus/permeability combinations were constructed using COMSOL MULTIPHYSICS software. A time dependent coupled pore pressure/effective stress analysis was used to model fluid/solid interactions in the scaffolds upon loading. Loading was simulated using an impermeable frictionless loader on the top boundary with fluid and solid displacement confined to the radial axis. As expected, all scaffold materials exhibited classic poro-elastic behavior having pressurized cores with low fluid flow and edges with high radial fluid velocities. Under the simulation parameters of this study, PEG scaffolds had the highest pressure and radial fluid velocity but also the lowest shear stress and radial strain. Chitosan and KLD-12 simulated scaffold materials had the lowest radial strains and fluid velocities, with collagen scaffolds having the lowest pressures. Parametric analysis showed maximum peak pressures within the scaffold to be more dependent on scaffold modulus than on permeability and velocities to depend on both scaffold properties similarly. The dependence of radial strain on permeability or modulus was more complex; maximum strains occurred at lower permeabilities and moduli, and the lowest strain occurred at the stiffest most permeable scaffold. Shear stresses within all scaffolds were negligible. These results give insight into the large variations in metabolic response seen in studies involving mechanical stimulation of cell-seeded constructs, where the same loading conditions produce very different results due to the differences in material properties.

X-ray microbeam and recrystallization studies of plastic deformation around fatigue cracks

X-ray microbeam technique and recrystallization method were used to measure plastic zones around 20 kHz fatigue cracks in mild steel. Both methods render approximately the same extension of a plastic zone. In order to obtain the amount of deformation within a plastic zone measurements of integral line breadth and recrystallization temperature were calibrated by specimens deformed with known per cent static tension. But since static and cyclic loading cause different dislocation structures (especially the dislocation density is much more inhomogeneous in fatigued specimens) quantitative comparison is difficult. Furthermore the two methods display different values of the actual amount of deformation. X-ray line broadening indicates an average dislocation density, whereas recrystallization displays a maximum amount of deformation, which corresponds to the local dislocation concentrations.