Crankshaft Stress Analysis—Combination of Finite Element and Classical Analysis Techniques

1990 ◽  
Vol 112 (3) ◽  
pp. 268-275 ◽  
Author(s):  
A. R. Heath ◽  
P. M. McNamara
Keyword(s):  
Stress Analysis ◽  
Concept Design ◽  
Low Friction ◽  
Failure Investigation ◽  
Engine Design ◽  
Computer Based ◽  
Analysis System ◽  
High Level ◽  
Engine Components ◽  
Oil Films

The conflicting legislative and customer pressures on engine design, for example, combining low friction and a high level of refinement, require sophisticated tools if competitive designs are to be realized. This is particularly true of crankshafts, probably the most analyzed of all engine components. This paper describes the hierarchy of methods used for crankshaft stress analysis with case studies. A computer-based analysis system is described that combines FE and classical methods to allow optimized designs to be produced efficiently. At the lowest level simplified classical techniques are integrated into the CAD-based design process. These methods give the rapid feedback necessary to perform concept design iterations. Various levels of FE analysis are available to carry out more detailed analyses of the crankshaft. The FE studies may feed information to or take information from the classical methods. At the highest level a method for including the load sharing effects of the flexible crankshaft within a flexible block interconnected by nonlinear oil films is described. This method includes the FE modeling of the complete crankshaft and the consideration of its stress field throughout an engine cycle. Fatigue assessment is performed to calculate the distribution of fatigue safety factor on the surface of the crankshaft. This level of analysis can be used for failure investigation, or detailed design optimization and verification. The method is compatible with those used for vibration and oil film analysis.

Computer Based Optimisation and Automation of Analysis and Design Processes in Aero Engine Development

2002 ◽  
Author(s):  
Alexander Karl ◽  
Roland Hansen ◽  
Michael Pfitzner
Keyword(s):  
Loose Coupling ◽  
Analysis And Design ◽  
Repetitive Tasks ◽  
Engine Design ◽  
Aero Engine ◽  
Computer Based ◽  
Aero Engines ◽  
Engine Components ◽  
Engine Development

Many variants of designs of different engine components have to be analysed in detail during the design and subsequent optimisation of modern aero engines. This often involves repetitive tasks and even today this process still contains a considerable amount of manual work for the majority of the tasks in the design process. Experts from different technical disciplines are involved and several different analysis tools are used. An automation of this process not only saves a lot of time during the design phase; it also increases the quality of the design since many more design variants can be screened. In the present paper the integration of different analysis codes and optimisation tools into an automated process using off-the-shelf software is described. A mix of commercial and in-house codes is integrated in a loose coupling way. Several applications from different areas of aero engine design are described. It is shown that in all cases the computer based optimisation and the process automation yields results of equal or better technical quality compared to the original hand optimised ones or improves the understanding of the design space. In addition, the necessary wall-clock time to reach the results was in all cases a fraction of that of the manual process.

Alchemy: Distributed financial quantitative analysis system with high‐level programming model

2021 ◽  
Author(s):  
Rong Gu ◽  
Zhixiang Zhang ◽  
Zhihao Xu ◽  
Zhaokang Wang ◽  
Kai Zhang ◽  
...  
Keyword(s):  
Quantitative Analysis ◽  
Programming Model ◽  
Analysis System ◽  
High Level

Development and Application of Graphics Displays for a Mini-Computer Based Vibration Analysis System

1992 ◽  
Author(s):  
Bill Trevillion
Keyword(s):  
Three Dimensional ◽  
Large Data ◽  
Electric Utility ◽  
Chemical Processing ◽  
Acoustic Data ◽  
Interactive Display ◽  
Computer Based ◽  
Data Files ◽  
Vibration Problems ◽  
Analysis System

Abstract Radian Corporation has developed extensive data display capabilities to analyze vibration and acoustic data from structures and rotating equipment. The Machinery Interactive Display and Analysis System (MIDAS) displays data collected through the acquisition functions of MIDAS. The graphics capabilities include displaying spectra in three-dimensional waterfall and in X-Y formats. Both types of plots can relate vibrations to time, equipment speed, or process parameters. Using menu-driven parameter selection, data can be displayed in formats that are the most useful for analysis. The system runs on a popular mini-computer, and it can be used with a great variety of graphics terminals, workstations, and printer/plotters. The software was designed and written for interactive display and plotting. Automatic plotting of large data files is facilitated by a batch plotting mode. The user can define display formats for the analysis of noise and vibration problems in the electric utility, chemical processing, paper, and automotive industries. This paper describes the history and development of graphics capabilities of the MIDAS system. The system, as illustrated in the examples, has proven efficient and economical for displaying large quantities of data.

Design for Assembly Evaluation of Orientation Difficulty Features

1992 ◽  
Author(s):  
Robert H. Sturges ◽  
Jui-Te Yang
Keyword(s):  
Geometric Modeling ◽  
Boundary Representation ◽  
Design For Assembly ◽  
Assembly Process ◽  
Assembly Evaluation ◽  
Index Of Difficulty ◽  
Analysis System ◽  
Time Required ◽  
High Level ◽  
Geometric Modeling System

Abstract In support of the effort to bring downstream issues to the attention of the designer as parts take shape, an analysis system is being built to extract certain features relevant to the assembly process, such as the dimension, shape, and symmetry of an object. These features can be applied to a model during the downstream process to evaluate handling and assemblability. In this paper, we will focus on the acquisition phase of the assembly process and employ a Design for Assembly (DFA) evaluation to quantify factors in this process. The capabilities of a non-homogeneous, non-manifold boundary representation geometric modeling system are used with an Index of Difficulty (ID) that represents the dexterity and time required to assemble a product. A series of algorithms based on the high-level abstractions of loop and link are developed to extract features that are difficult to orient, which is one of the DFA criteria. Examples for testing the robustness of the algorithms are given. Problems related to nearly symmetric outlines are also discussed.

Comparison of Piston Concept Design Solutions for Composite Cycle Engines Part II: Design Considerations

2021 ◽  
Author(s):  
Dimitrios Chatzianagnostou ◽  
Stephan Staudacher
Keyword(s):  
Gas Turbine ◽  
Design Space ◽  
Piston Compressor ◽  
Design System ◽  
Surface Load ◽  
Preliminary Design ◽  
Concept Design ◽  
Piston Engine ◽  
Engine Design ◽  
Cylinder Piston

Abstract Hecto pressure composite cycle engines with piston engines and piston compressors are potential alternatives to advanced gas turbine engines. The nondimensional groups limiting their design have been introduced and generally discussed in Part I [1]. Further discussion shows, that the ratio of effective power to piston surface characterizes the piston thermal surface load capability. The piston design and the piston cooling technology level limit its range of values. Reynolds number and the required ratio of advective to diffusive material transport limit the stroke-to-bore ratio. Torsional frequency sets a limit to crankshaft length and hence cylinder number. A rule based preliminary design system for composite cycle engines is presented. Its piston engine design part is validated against data of existing piston engines. It is used to explore the design space of piston components. The piston engine design space is limited by mechanical feasibility and the crankshaft overlap resulting in a minimum stroke-to-bore ratio. An empirical limitation on stroke-to-bore ratio is based on existing piston engine designs. It limits the design space further. Piston compressor design does not limit the piston engine design but is strongly linked to it. The preliminary design system is applied to a composite cycle engines of 22MW take-off shaft power, flying a 1000km mission. It features three 12-cylinder piston engines and three 20-cylinder piston compressors. Its specific fuel consumption and mission fuel burn are compared to an intercooled gas turbine with pressure gain combustion of similar technology readiness.

Comparison of Prescription and Medical Records in Reflecting Patient Antihypertensive Drug Therapy

1994 ◽  
Vol 28 (1) ◽  
pp. 99-104 ◽  
Author(s):  
Dale B. Christensen ◽  
Barbara Williams ◽  
Harold I. Goldberg ◽  
Diane P. Martin ◽  
Ruth Engelberg ◽  
...  
Keyword(s):  
Medical Record ◽  
Medical Records ◽  
Health Maintenance Organizations ◽  
Antihypertensive Drug Therapy ◽  
Antihypertensive Medications ◽  
Pharmacy Records ◽  
Health Maintenance ◽  
Computer Based ◽  
High Level ◽  
Level Of Agreement

OBJECTIVE: To determine the completeness of prescription records, and the extent to which they agreed with medical record drug entries for antihypertensive medications. SETTING: Three clinics affiliated with two staff model health maintenance organizations (HMOs). PARTICIPANTS: Randomly selected HMO enrollees (n=982) with diagnosed hypertension. METHODS: Computer-based prescription records for antihypertensive medications were reviewed at each location using an algorithm to convert the directions-for-use codes into an amount to be consumed per day (prescribed daily dosage). The medical record was analyzed similarly for the presence of drug notations and directions for use. RESULTS: There was a high level of agreement between the medical record and prescription file with respect to identifying the drug prescribed by drug name. Between 5 and 14 percent of medical record drug entries did not have corresponding prescription records, probably reflecting patient decisions not to have prescriptions filled at HMO-affiliated pharmacies or at all. Further, 5–8 percent of dispensed prescription records did not have corresponding medical record drug entry notations, probably reflecting incomplete recording of drug information on the medical record. The percentage of agreement of medical records on dosage ranged from 68 to 70 percent across two sites. Approximately 14 percent of drug records at one location and 21 percent of records at the other had nonmatching dosage information, probably reflecting dosage changes noted on the medical record but not reflected on pharmacy records. CONCLUSIONS: In the sites studied, dispensed prescription records reasonably reflect chart drug entries for drug name, but not necessarily dosage.

Computer Based Process Piping Stress Analysis: ASME B31.3 Appendix S — Example S2

2006 ◽  
Author(s):  
Don R. Edwards
Keyword(s):  
Stress Analysis ◽  
Operating Temperature ◽  
Stress Range ◽  
Explicit Equation ◽  
The Past ◽  
Process Piping ◽  
Piping Systems ◽  
Sustained Loads ◽  
Computer Based ◽  
Temperature And Pressure

The American Standards Association (ASA) B31.3-1959 Petroleum Refinery Piping Code [1] grew out of an ASA document that addressed all manner of fluid conveying piping systems. ASA B31.3 was created long before widespread engineering use of computer “mainframes” or even before the inception of piping stress analysis software. Also as B31.3 continued to pass thru standards organizations from ASA, ANSI, to ASME, the B31.3 Process Piping Code [2] (hereafter referred to as the “Code”) has remained ambiguous over the past few decades in several areas. The displacement stress range, SE, has always been explicitly defined by both verbiage and equation. Yet, the sustained condition(s) stress, SL, is mentioned not with an explicit equation but with a statement that the sustained stress shall be limited by the allowable stress at the corresponding operating temperature, Sh. Also one might infer from the vague verbiage in the Code that there is only one sustained condition; this would also be an incorrect inference. Also, assumptions would then have to be made as to which supports are allowed to be included in a sustained analysis based on whether the piping “lifts-off” any of the pipe supports during the corresponding operating condition. This paper describes the subtle yet possibly radical concepts that are included in the (recently approved for inclusion into) ASME B31.3-2006 Appendix S Example S2. This paper discusses: • when and in what manner the most severe set of operating temperature and pressure is to be used; • the concept of “sustained condition” and multiple “anticipated” sustained conditions; • determining the support scenario(s) for each anticipated sustained condition; • establishing the most severe sustained condition to evaluate and determine the stress due to sustained loads, SL; • utilizing an equation with sustained stress indices to evaluate SL; • establishing the least severe sustained condition and its effect in determining the largest displacement stress range, SE.

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