Analisis Konstruksi Pipa Pompa Suction 112-JB

The 101-JTC condenser tank has excess steam condensate due to the addition of admission steam from 101-JT. Therefore, it is necessary to design a piping system that connects 101-JTC condenser tank with the 112-JB pump to drain the condensed excess steam. The designed piping system will encounter a dynamic response caused by fluid flow fluctuation over the time. This dynamic response causes the pipe to experience stress. To find out the resulting voltage which will not cause damage or failure, it is necessary to estimate the safety factor in a piping system that has been given static and dynamic loading. This research uses the fluid structure interaction or FSI method with the help of ANSYS software as a simulation tool. The results of this study are, the flow in the pipe causes an impact load which makes the structure vibrate freely damped. The resulting dynamic response describes, the structure displacement amplitude decreases with increasing time. This indicates a stable vibration. Finally, when viewed from the value of stress against time, the fatigue that occurs in the pipe structure induce a stress below the stress limit on Goodman diagram. It can be estimated that the structure has no service life limit. The fatigue safety factor is 7.1.

Transformative Use of Additive Technology in Design and Manufacture of Hydraulic Actuator for Fly-by-Wire System

In this paper, the results of research on additively manufactured aerospace parts made of maraging steel are presented. This state-of-the-art technology seems to have the highest potential for practical use in the field of ultra-light and high-performance aerospace hydraulic parts. The strength properties of representative specimens made with steel 1.2709 were investigated. The researchers conducted static tensile testing, fatigue tensile testing, and pressure impulse testing. A Goodman diagram was plotted to visualize the impact of the building orientation vs. load character on the fatigue strength of the additive manufacturing (AM) specimens. Based on the research carried out on the strength of the AM samples, an aircraft flight control actuator was designed to achieve the highest level of safety integrity along with the greatest simplicity and lowest weight relative to hydraulic actuators manufactured using classical methods. The entire design process was integrated with the manufacturing process to achieve this target.

Fatigue behavior of stent in tapered arteries: The role of arterial tapering and stent material

Stenting has achieved great success in treating cardiovascular diseases due to its high efficiency and minimal invasiveness. However, fatigue of stents severely limits its long-term outcome. In this article, finite element method was adopted to study the effects of arterial tapering and stent material on the fatigue performance of stents. A series of tapered vessels with different taper levels and two sets of stents with different materials were modeled. The Goodman diagram was used to evaluate the fatigue resistance of stents. Results showed that the fatigue resistance of stents can be extremely improved by simply changing stent material. In addition, the taper of the arteries had an important influence on the fatigue resistance of the stent. The fatigue life of the stent will be shortened with the increase of the arterial taper. The method that predicted stent fatigue life in tapered vessels can help clinicians select stents that are more suitable for tapered vessels and help stent engineers design stents that are more resistant to fatigue.

Fatigue Reliability Assessment of a Metro-Train Bolster

The bolster is a key structure for the metro train. To evaluate its fatigue reliability under the fatigue loading scheme, the full-scale fatigue test and theoretical calculation are performed. The bolster is modeled as a series system of stress concentration zones, namely weak points, and their stresses are calculated using validated finite element method (FEM). Since no fatigue crack is observed after the test and the fatigue life predicted by the Goodman diagram is more than [Formula: see text] load cycles, the bolster can service for more than 30 years with 90% reliability. To learn more about its fatigue reliability during the real service, a fatigue reliability model is established based on stress-life interference model. 10 load spectra are generated by Poisson processes, and the bolster is also modelled as a series system of six weak points. As a result, its cumulative failure probability is less than 0.002% within its 30-year service under normal atmospheric conditions.

Influence of the Realistic Artery Geometry Parameters on a Coronary Stent Fatigue Life

The stents’ adaptability and safety in realistic and idealized stenotic coronary model were compared to investigate the influence of artery geometry parameter on stent fatigue life. The stents’ fatigue resistance ability was calculated using Goodman diagram, and the cycle to failure, the fatigue life, and the fatigue safety factor (FSF) were analyzed. Although the peak top of the von Mises stress was located at the bending area of crowns, the stress distributions were different in the two models. Considering the safety and accuracy, it is necessary to use a realistic geometric model to calculate the stent fatigue performance.

Structural Design and Analysis of Cylindrical Squirrel Cage to Meet Stiffness, Strength and High Cycle Fatigue Life for an Aero Engine

Squeeze film dampers have traditionally been used in aircraft engine to overcome stability and vibration problems that are not adequately handled with conventional style bearings. One of the key design features in a squeeze film damper [1] configuration is the introduction of flexibility in the bearing support. The simplest means to provide the support flexibility in the squeeze film damper is through the use of squirrel cage [2]. This paper deals with structural design analysis of cylindrical squirrel cage of an aircraft engine. Design of the squirrel cage needs a balance between stiffness and strength requirements. To meet the strength, stiffness and fatigue life requirements, squirrel cage web dimensions and fillet radius are modified. The various configurations of the squirrel cage have been evaluated to arrive at the optimum design. Stress analysis of the bearing has been carried out for axial, radial unbalance loads. Stress distribution in the web region has been studied in detail. High cycle fatigue life margins are estimated using Goodman diagram. The squirrel cage web dimensions and fillet radius are modified to improve HCF life requirements. The operating stresses in the squirrel cage are reduced while meeting the stiffness and HCF life requirements of the component.

Light Weight Freight Rolling Stock Bogie Frame: Design Methodology Validated with Field Oscillation Trials

Indian railway has improved the laden to tare weight ratio by producing lighter as well as higher strength bogie frame of freight rolling stock. Bogie frame is the crucial component of the rail vehicle which carries static load in the form of gross weight and dynamic loads arising from various track and wheel irregularities. The three piece freight vehicle bogie frame comprises two side frames and one bolster. The side frame; fitted with three piece bogie frame and responsible for the ride quality of the freight vehicle, is considered in present study. The locations suitable for weight reduction are found by finite element analysis (FEA), using side frame solid model in MSC FEA environment. International standards of the association of American railroad (AAR specification M-203) [1] load cases and boundary conditions are deployed for analysis in the context of the operating scenario of Indian railways. Typical Indian railway track signatures are used as input for transient analysis. Time dependent stresses at critical speeds are used for fatigue strength evaluation as per Goodman diagram. The modified design is approx. 13.90% lighter and sustains 25.00 ton axle load in comparison of earlier 22.00 ton. Suggested topological changes have been compared by using frequencies of the initial and modified designs. Further, based on Indian railways running conditions, actual assessment and trial of the modified design bogie frame prototype has been carried out by Research Designs and Standards Organisation (RDSO) [2]. The results of the trial are found to be satisfactory and within the prescribed range.

Verification of Class B S-N Curve for Fatigue Design of Forged Steel Connectors

The fatigue design of forged steel connectors in steel catenary risers (SCRs) is commonly based on the BS 7608 Class B S-N curve, which was derived from longitudinal butt weld data. However, there is very little direct support for this. Therefore, its validity was checked by performing a fatigue test programme involving strip specimens extracted from actual forged J-lay connectors. The effects of stress ratio and surface roughness on fatigue strength were investigated. On the basis of these test results, together with available published data obtained from specimens or structural components that failed in plain steel, the Class B S-N curve was verified. The method was particularly conservative for low stress ratios in the high-cycle regime and a procedure based on the use of the Goodman diagram was devised for correcting the Class B curve for mean stress. Surface roughness in the range investigated, between 3.2 and 8.1μm in Ra, had little effect on the fatigue performance of the forged steel.

Impulse Testing and Blade Load Simulation Tools to Estimate Cyclic Stress Life in Blades and Impellers

A pragmatic approach for estimating cyclic stresses in rotating airfoils based on impulse testing with strain gauge sensors and application of simplified aerodynamic excitations is presented. The method has been successfully applied to determine the root causes of blade and impeller failures in gas turbines, steam turbines, and industrial compressors. The method provides guidance for quickly determining the natural frequency most responsible for a failure by analyzing experimental stress data at blade resonances, incorporating the Campbell diagram to evaluate frequency margins, and applying the Goodman diagram to evaluate endurance stress margins. The effects of mis-tuned blade responses can be included and operating lifetimes can be evaluated by use of the Palmgren-Miner analysis. Example cases of significant failure analyses for an axial flow gas turbine compressor and a driven industrial compressor are used to illustrate how the method is used.

Effect of Mean Stress on Fatigue Strength of Non-Combustible Magnesium Alloy

Effect of mean stress on fatigue strength at N=107 of non-combustible magnesium alloy AMX602B(X=Ca) was investigated. Rotating bending fatigue test and tension-compression fatigue test were carried out on specimens with a small hole or crack. It was clarified that the fatigue strength at N=107 of the specimen with the small hole was about 30-150% higher than that of the specimen with the small crack within the range of σm=0~100MPa. This is the reason why the fatigue strength at N=107 of the specimen with the small hole can be not threshold condition for crack propagation but crack initiation. The fatigue strength at N=107 of the specimens with the small hole decreased within the range of σm=100~195MPa due to a static small crack initiating from the small hole at first loading. The effect of mean stress on fatigue strength at N=107 both oh the specimens with the small hole and crack could be estimated using modified Goodman diagram.