Equal Life Optimization of Shells Based on Kiln Axis Alignment

2013 ◽  
Vol 404 ◽  
pp. 257-262 ◽  
Author(s):  
Xiao Yan Yang ◽  
You Gang Xiao ◽  
Xian Ming Lei
Keyword(s):  
Fatigue Life ◽  
Life Expectancy ◽  
Load Distribution ◽  
Fuzzy Optimization ◽  
Remaining Life ◽  
Design Variables ◽  
Stress Spectrum ◽  
Axis Alignment ◽  
Asymmetric Load ◽  
Set Up

The crack of kiln shells was seen regularly due to axis deflection and asymmetric load distribution. It will be helpful to improve kiln performance if the remaining life of kiln shells can be kept the same. For this the formulae of stress spectrum and fatigue life of kiln shells are obtained. Taking the aligned values of axis deflections as design variables, equal fatigue life of shells and maximum axis deflection as the objective function, considering the fuzzy factors during axis alignment, the fuzzy optimization model of kiln axis alignment is set up. The results indicate that kiln axis can be aligned as direct as possible, and life expectancy of kiln shells can be optimized to keep near the same. Accordingly, the valuable production time of kiln can be increased greatly by such aligned method.

Optimum Autofrettage and Shrink-Fit Combination in Multi-Layer Cylinders

2005 ◽  
Vol 128 (2) ◽  
pp. 196-200 ◽  
Author(s):  
Hamid Jahed ◽  
Behrooz Farshi ◽  
Morvarid Karimi
Keyword(s):  
Fatigue Life ◽  
Life Expectancy ◽  
Crack Depth ◽  
Optimization Procedure ◽  
Optimization Method ◽  
Stress Constraints ◽  
Simplex Search ◽  
Design Variables ◽  
Significant Life ◽  
Shrink Fit

The interest in the use of layered cylinders that combine autofrettage and shrink fit in order to extend fatigue lifetimes is increasing. As the number of layers increases, the sequential order of assembly and the size of each layer become more important. To achieve the most benefical result, a design optimization method is required. In this investigation, the optimum design of a three-layered vessel for maximum fatigue life expectancy under the combined effects of autofrettage and shrink fit has been considered. To obtain optimum size of each layer and to optimize the initial stress distribution, the numerical optimization procedure known as the Simplex search method is employed here. The thickness of each layer, shrink-fit pressures, and autofrettage percentages are treated as design variables. Under stress constraints, the operational sequences for assembly of a layered vessel have been formulated in order to lead to optimum results, defined as maximum life expectancy. The fatigue life consideration is based on ASME code provisions and standards for high pressure vessel technology, which define the allowable final crack depth for multilayer vessels. The proposed procedure has been carried out on a number of examples. The results show that, with proper combination of operations significant life enhancement can be achieved using the optimization procedure.

scholarly journals Modeling, Simulation and Uncertain Optimization of the Gun Engraving System

Mathematics ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 398
Author(s):  
Tong Xin ◽  
Guolai Yang ◽  
Fengjie Xu ◽  
Quanzhao Sun ◽  
Alexandi Minak
Keyword(s):  
Performance Evaluation ◽  
Optimal Design ◽  
Resistance Force ◽  
Gas Temperature ◽  
Evaluation Indexes ◽  
Uncertain Optimization ◽  
Design Variables ◽  
Set Up ◽  
Rotating Band ◽  
Percent Decrease

The system designed to accomplish the engraving process of a rotating band projectile is called the gun engraving system. To obtain higher performance, the optimal design of the size parameters of the gun engraving system was carried out. First, a fluid–solid coupling computational model of the gun engraving system was built and validated by the gun launch experiment. Subsequently, three mathematic variable values, like performance evaluation indexes, were obtained. Second, a sensitivity analysis was performed, and four high-influence size parameters were selected as design variables. Finally, an optimization model based on the affine arithmetic was set up and solved, and then the optimized intervals of performance evaluation indexes were obtained. After the optimal design, the percent decrease of the maximum engraving resistance force ranged from 6.34% to 18.24%; the percent decrease of the maximum propellant gas temperature ranged from 1.91% to 7.45%; the percent increase of minimum pressure wave of the propellant gas ranged from 0.12% to 0.36%.

The Influencing Factors and Assessment Rule of Fatigue Life of Shaft Based on Product Lifecycle Management

2007 ◽  
Vol 561-565 ◽  
pp. 2253-2256 ◽  
Author(s):  
You Tang Li ◽  
Ping Ma ◽  
Jun Tian Zhao
Keyword(s):  
Fatigue Life ◽  
Influencing Factors ◽  
Axial Stress ◽  
Assessment Method ◽  
Product Lifecycle Management ◽  
Product Lifecycle ◽  
Fatigue Design ◽  
Main Factors ◽  
Set Up ◽  
Lifecycle Management

Product lifecycle management is one of the main developmental aspects of advanced manufacturing technology. Anti-fatigue design is the key content in product lifecycle management. For designing the fatigue life of shaft exactly and determining the assessment method, the influencing factors must be realized roundly. The mechanical model of shaft is set up at first, and then the main factors that affect the fatigue life of shaft is discussed, the interrelations of the main factors and the framework are founded. The assessment equation of fatigue life for shaft is put forward and the influencing coefficient of multi-axial stress to fatigue life is analyzed. The results of this paper will establish the base of anti-fatigue and assessment life of shaft.

Osteoarthritis of the Wrist: Pathology, Radiology, and Treatment

2021 ◽  
Vol 25 (02) ◽  
pp. 294-303
Author(s):  
Jan-Peter Grunz ◽  
Carsten Herbert Gietzen ◽  
Georgios Christopoulos ◽  
Jörg van Schoonhoven ◽  
Florian Goehtz ◽  
...  
Keyword(s):  
Load Distribution ◽  
Synovial Joint ◽  
Close Collaboration ◽  
Degenerative Arthritis ◽  
Specific Patient ◽  
Rapid Disease Progression ◽  
Joint Surfaces ◽  
Osteoarthritis Of The Wrist ◽  
Advanced Stages ◽  
Asymmetric Load

AbstractOsteoarthritis (OA) is a degenerative disease that can manifest in any synovial joint under certain conditions. It leads to destruction of articular cartilage and adjacent bone, as well as formation of osteophytes at the edges of afflicted joint surfaces. Regarding the wrist, typical degenerative arthritis affects particular joints at a specific patient age, due to asymmetric load distribution and repetitive microtrauma. However, in the presence of instability or systemic diseases, early-onset degeneration can also impair the range of motion and grip strength in younger patients. Although advanced stages of OA display characteristic signs in radiography, the detection of early manifestations frequently requires computed tomography or magnetic resonance imaging (in some cases with additional arthrography). If a wrist becomes unstable, timely diagnosis and precise treatment are essential to prevent rapid disease progression. Therefore, close collaboration between radiologists and hand surgeons is obligatory to preserve the carpal function of patients.

A Study on Optimum Design Using Fuzzy Numbers As Design Variables

1995 ◽  
Author(s):  
Masao Arakawa ◽  
Hiroshi Yamakawa
Keyword(s):  
Fuzzy Sets ◽  
Optimum Design ◽  
Fuzzy Numbers ◽  
Fuzzy Optimization ◽  
Design Parameters ◽  
Numerical Examples ◽  
Design Variables ◽  
Conventional Methods

Abstract In this study, we summerize the method of fuzzy optimization using fuzzy numbers as design variables. In order to detect flaw in fuzzy calculation, we use LR-fuzzy numbers, which is known as its simplicity in calculation. We also use simple fuzzy numbers’ operations, which was proposed in the previous papers. The proposed method has unique characteristics that we can obtain fuzzy sets in design variables (results of the design) directly from single numerical optimizing process. Which takes a large number of numerical optimizing processes when we try to obtain similar results in the conventional methods. In the numerical examples, we compare the proposed method with several other methods taking imprecision in design parameters into account, and demonstrate the effectiveness of the proposed method.

A Method for Fatigue Analysis of Pipelines on Topsides of FPSO Systems

2005 ◽  
Author(s):  
Pol Spanos ◽  
Alba Sofi ◽  
Juan Wang ◽  
Berry Peng
Keyword(s):  
Fatigue Life ◽  
Random Vibration ◽  
Equations Of Motion ◽  
Plug Flow ◽  
Fatigue Curve ◽  
Sea Waves ◽  
Random Loading ◽  
Euler Beam ◽  
Stress Spectrum ◽  
The Galerkin Method

Pipelines located on the decks of FPSO systems are exposed to damage due to sea waves induced random loading. In this context, a methodology for estimating the fatigue life of conveying-fluid pipelines is presented. The pipeline is subjected to a random support motion which simulates the effect of the FPSO heaving. The equation of motion of the fluid-carrying pipeline is derived by assuming small amplitude displacements, modeling the empty pipeline as a Bernoulli-Euler beam, and adopting the so-called “plug-flow” approximation for the fluid (Pai¨doussis, 1998). Random vibration analysis is carried out by the Galerkin method selecting as basis functions the natural modes of a beam with the same boundary conditions as the pipeline. The discretized equations of motion are used in conjunction with linear random vibration theory to compute the stress spectrum for a generic section of the pipeline. For this purpose, the power spectrum of the acceleration at the deck level is determined by using the Response Amplitude Operator of the FPSO hull. Finally, the computed stress spectrum is used to estimate the pipeline fatigue life employing an appropriate S-N fatigue curve of the material. An illustrative example concerning a pipeline simply-supported at both ends is included in the paper.

Concrete Fatigue Life Characteristics of the Different Survival Rates in the Lateral Pressure Conditions

2012 ◽  
Vol 600 ◽  
pp. 250-255
Author(s):  
Qiang Cai ◽  
Ji Ming Kong ◽  
Ze Fu Chen
Keyword(s):  
Fatigue Life ◽  
Life Stress ◽  
Failure Modes ◽  
Survival Curve ◽  
Survival Rates ◽  
Life Distribution ◽  
Fatigue Design ◽  
Set Up ◽  
Fatigue Equation ◽  
Two Parameter

Under cyclic loading of concrete structures, fatigue failure is the main failure modes of fatigue, which has become the fatigue design of concrete structure must be considered, then the concrete fatigue studies must clarify the fatigue life of concrete under different survival curve S-N curve. Based on the statistics of the two parameter Weibull distribution theory, obtain the concrete under different survival rates of fatigue life distribution, namely to improve survival, reduce the fatigue life; stress level is reduced, the fatigue life is increased; and has set up more than 50% under different survival rates of concrete fatigue equation.

scholarly journals Neighborhood Disadvantage and Active, Disabled and Total Life Expectancy Among Community-living Older Persons

2021 ◽  
Author(s):  
Thomas M. Gill ◽  
Emma X. Zang ◽  
Terrence E. Murphy ◽  
Linda Leo-Summers ◽  
Evelyne A. Gahbauer ◽  
...  
Keyword(s):  
Prognostic Factors ◽  
Life Expectancy ◽  
Older Persons ◽  
Neighborhood Disadvantage ◽  
Community Living ◽  
Remaining Life ◽  
Disadvantaged Group ◽  
Individual Level ◽  
Total Life Expectancy ◽  
Total Life

AbstractBackgroundNeighborhood disadvantage is a novel social determinant of health that could adversely affect the functional well-being and longevity of older persons. We evaluated whether estimates of active, disabled and total life expectancy differ on the basis of neighborhood disadvantage after accounting for individual-level socioeconomic characteristics and other prognostic factors.MethodsWe used data on 754 community-living older persons from South Central Connecticut, who completed monthly assessments of disability from 1998 to 2020. Scores on the area deprivation index were dichotomized at the 80th state percentile to distinguish neighborhoods that were disadvantaged (81-100) from those that were not (1-80).ResultsWithin 5-year age increments from 70 to 90, active and total life expectancy were consistently lower in participants from neighborhoods that were disadvantaged versus not disadvantaged, and these differences persisted and remained statistically significant after adjustment for individual-level race/ethnicity, education, income, and other prognostic factors. At age 70, adjusted estimates (95% CI) for active and total life expectancy (in years) were 12.3 (11.5-13.1) and 15.0 (13.8-16.1) in the disadvantaged group and 14.2 (13.5-14.7) and 16.7 (15.9-17.5) in the non-disadvantaged group. At each age, participants from disadvantaged neighborhoods spent a greater percentage of their projected remaining life disabled, relative to those from non-disadvantaged neighborhoods, with adjusted values (SE) ranging from 17.7 (0.8) vs. 15.3 (0.5) at age 70 to 55.0 (1.7) vs. 48.1 (1.3) at age 90.ConclusionsLiving in a disadvantaged neighborhood is associated with lower active and total life expectancy and a greater percentage of projected remaining life disabled.

scholarly journals Growing Income-Based Inequalities in Old-Age Life Expectancy in Sweden, 2006–2015

Demography ◽  
2021 ◽  
Author(s):  
Stefan Fors ◽  
Jonas W. Wastesson ◽  
Lucas Morin
Keyword(s):  
Income Inequality ◽  
Life Expectancy ◽  
Life Span ◽  
Old Age ◽  
Remaining Life ◽  
Neighborhood Deprivation ◽  
Income Gap ◽  
Remaining Life Expectancy ◽  
Mortality Improvement ◽  
Income Quartile

Abstract Sweden is known for high life expectancy and economic egalitarianism, yet in recent decades it has lost ground in both respects. This study tracked income inequality in old-age life expectancy and life span variation in Sweden between 2006 and 2015, and examined whether patterns varied across levels of neighborhood deprivation. Income inequality in remaining life expectancy at ages 65, 75, and 85 increased. The gap in life expectancy at age 65 grew by more than a year between the lowest and the highest income quartiles, for both men (from 3.4 years in 2006 to 4.5 years in 2015) and women (from 2.3 to 3.4 years). This widening income gap in old-age life expectancy was driven by different rates of mortality improvement: individuals with higher incomes increased their life expectancy at a faster rate than did those with lower incomes. Women with the lowest incomes experienced no improvement in old-age life expectancy. Furthermore, life span variation increased in the lowest income quartile, while it decreased slightly among those in the highest quartile. Income was found to be a stronger determinant of old-age life expectancy than neighborhood deprivation.

Analytical determination of the optimal clearance for the fatigue life of ball bearing under different load conditions

2021 ◽  
pp. 1-28
Author(s):  
Bin Fang ◽  
Jinhua Zhang
Keyword(s):  
Fatigue Life ◽  
Load Distribution ◽  
Life Prediction ◽  
Ball Bearing ◽  
Operating Conditions ◽  
Analytical Determination ◽  
Parameters Selection ◽  
Bearing Life ◽  
Structural Design Optimization ◽  
Load Conditions

Abstract In this paper, a comprehensive analytical model for the fatigue life prediction of ball bearing in various operating conditions is presented. Not only the internal clearance variations induced by the centrifugal expansion and assembly interference, but also ball inertia forces and ball-raceway separations are fully considered in theoretical modeling to achieve accurate life prediction of ball bearing. The model has been validated by comparison with the static results in previous literature. Based on this, the results of the load distribution and fatigue life versus the internal clearance of ball bearing under various operating conditions are studied. The results show that there is always an optimal clearance to maximize bearing fatigue life for the radial load or the combined load conditions, and the size of the optimal clearance for bearing life is determined by both the load conditions and rotating speeds to ensure the uniformity of the internal load distribution of the ball bearing. Therefore, the above theoretical and conclusions can be used in structural design optimization and assembly parameters selection of ball bearing to maximize the life characteristic.

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