ABOUT SAFETY FACTOR LOAD FOR SOIL DW IN GEOTECHNICS

2016 ◽  
Vol 4 (3) ◽  
pp. 0-0
Author(s):  
Алексей Радкевич ◽  
Aleksey Radkevich ◽  
Александр Митькин ◽  
Aleksandr Mitkin ◽  
Б Кулачкин ◽  
...  
Keyword(s):  
Body Weight ◽  
Safety Factor ◽  
Safety Factors ◽  
Main Criterion ◽  
Reliability Coefficients

Reliability coefficients on loading from a body weight of metal, concrete and soil are considered. The analysis of the evolution of safety factors for load from its own weight. Noted that the safety factor of load from the weight of the soil is the main criterion of reliability and safety in Geotechnics and construction in General. Admitted blunder in SP 20.13330.2011. Heterogeneity of soil character bedding are the main characteristics that fully characterize the company according to the static sounding. The reliability coefficients for the load of its own weight soils significantly underestimated and may not be practically identical with concrete. It is recommended that you increase the value of the coefficient of reliability of load from the weight of the soil, and correct the terminology.

Limit State Philosophy in Pipeline Design

1987 ◽  
Vol 109 (1) ◽  
pp. 9-22 ◽  
Author(s):  
C. P. Ellinas ◽  
P. W. J. Raven ◽  
A. C. Walker ◽  
P. Davies
Keyword(s):  
Structural Analysis ◽  
Safety Factor ◽  
Current Knowledge ◽  
Limit State ◽  
Structural Behavior ◽  
Major Conclusion ◽  
Safety Factors ◽  
Suitable Framework ◽  
General Aspects ◽  
Pipeline Design

This paper considers the application of the limit state philosophy of structural analysis to pipeline design. General aspects of the philosophy are discussed and the approach to the evaluation of safety factors is reviewed. The paper further considers the various limit and serviceability states which would be relevant to a pipeline and reviews the various factors which may require consideration, before a code embodying the limit state philosophy could be formulated. A review of the state of current knowledge on various aspects of geometry and material characteristics, loading and structural behavior is presented. It is intended that such a review can be used as the basis for a larger study to provide guidance and data for the evaluation of rational levels of safety factor. The major conclusion reached by the authors is that a limit state philosophy would be valuable in providing a suitable framework, which may highlight the significant aspects of pipeline design and which can most easily accommodate new requirements and results obtained from research.

Improved defibrillator waveform safety factor with biphasic waveforms

1983 ◽  
Vol 245 (1) ◽  
pp. H60-H65 ◽  
Author(s):  
J. L. Jones ◽  
R. E. Jones
Keyword(s):  
Safety Factor ◽  
Voltage Gradient ◽  
Excitation Threshold ◽  
Efficacy And Safety ◽  
Myocardial Cells ◽  
Safety Factors ◽  
Adult Type ◽  
Intracellular Microelectrodes ◽  
Cultured Myocardial Cells

Excitation thresholds and arrhythmias were studied in "adult-type" cultured chick embryo myocardial cells after electric field stimulation with biphasic, truncated, and rectified underdamped RLC (resistance-inductance-capacitance) type waveforms, to test the hypothesis that the negative phase of biphasic waveforms ameliorates membrane dysfunction induced by the initial positive portion. Photocell mechanograms and intracellular microelectrodes monitored extrasystoles and depolarization-induced arrhythmias. Rectifying or truncating biphasic waveforms did not alter the excitation threshold. However, shock intensities producing specific postshock arrhythmias or a specific severity of postshock prolonged depolarization differed significantly when biphasic waveforms were truncated or rectified. The voltage gradient producing a specific dysfunction was 12-14% lower for the truncated version than for the biphasic; that for the rectified version was 17-27% lower than for the biphasic version (although both contained the same energy). Safety factor, the ratio between shock intensity producing specific dysfunction and that producing excitation, was determined for each waveform. Biphasic waveforms had larger safety factors than truncated or rectified waveforms. Since safety factor, as measured in cultured myocardial cells, closely corresponds with in situ defibrillating effectiveness (14), the significantly higher safety factors of biphasic waveforms suggest that carefully shaped biphasic waveforms might improve the efficacy and safety of cardiac defibrillation procedures.

Safety Factor in Fatigue Under Fluctuating Stresses

1987 ◽  
Vol 109 (4) ◽  
pp. 397-401 ◽  
Author(s):  
V. A. Avakov
Keyword(s):  
Safety Factor ◽  
High Cycle Fatigue ◽  
Stress Amplitude ◽  
Static Strength ◽  
Mean Stress ◽  
Cycle Fatigue ◽  
Safety Factors ◽  
Generalize Expression ◽  
Allowable Stresses ◽  
Number Of Cycles

It is common to assume identical allowable safety factors in static strength [m], defined by mean stress (Sm), and in fatigue [a], defined by stress amplitude (Sa), in order to find the full safety factor (F) under asymmetrical cycles, or to plot any type of the Sm–Sa diagram of allowable stresses. Here additional modification is considered to generalize expression of the full factor of safety in fatigue under asymmetrical stresses, utilizing unequal allowable safety factors in static strength (by mean stress) and in fatigue (by stress amplitude): ([a] ≠ [m]). We assume that loading is stationary, and cumulated number of cycles is large enough to consider high cycle fatigue.

Substantiation of probabilistic safety factors as a factor for optimizing the metal consumption of pipelines and the permissible operating pressure

2021 ◽  
pp. 364-371
Author(s):  
Юрий Григорьевич Матвиенко ◽  
Дмитрий Александрович Кузьмин ◽  
Владимир Васильевич Зацаринный ◽  
Максим Сергеевич Пугачев ◽  
Владимир Вячеславович Потапов
Keyword(s):  
Safety Factor ◽  
Probability Of Failure ◽  
Fracture Probability ◽  
Operating Pressure ◽  
Pipe Steels ◽  
Safety Factors ◽  
Metal Consumption ◽  
Load Variation ◽  
Coefficients Of Variation ◽  
The Given

Проведен анализ влияния коэффициентов вариации сопротивления материала разрушению и коэффициентов вариации нагрузки на вероятность разрушения и, следовательно, на коэффициенты запаса по характеристикам сопротивления материала разрушению при заданных показателях вероятности разрушения. Снижение неопределенности в условиях нагружения и повышение качества материала позволяют снизить коэффициенты запаса по пределу текучести и вязкости разрушения для заданных целевых показателей безопасности. На примере трубных сталей марок Ст 20 и 16ГС показана возможность снижения коэффициента запаса по пределу текучести до значений n = 1,45 при коэффициенте вариации нагрузки 0,1 и сохранении целевого показателя безопасности в терминах вероятности разрушения на уровне 10. Возможность снижения коэффициентов запаса по пределу текучести и вязкости разрушения при заданных целевых показателях безопасности в терминах вероятности разрушения позволяет оптимизировать металлоемкость и максимальные допустимые давления в эксплуатируемых трубопроводах. The analysis of the influence of the coefficients of variation of the material resistance and the coefficients of the load variation on the probability of failure as well as on the safety factors for the characteristics of the material resistance to failure has been done at given indicators of the probability of failure. Reducing uncertainty under loading conditions and improving material quality allow reducing the safety factors against fracture and collapse for given targets safety. Using the example of pipe steels of grades St 20 and 16GS, it seems possible to reduce the safety factor against collapse up to 1.45 with a load variation coefficient of 0.1 and maintaining the safety target in terms of the fracture probability at the level of 10. The possibility of reducing the safety factors against collapse and fracture at the given target safety indicators in terms of the fracture probability allows optimizing the metal consumption and the maximum allowable pressures in the operating pipelines.

Hydraulic conductance of lung endothelial phenotypes and Starling safety factors against edema

2007 ◽  
Vol 292 (2) ◽  
pp. L378-L380 ◽  
Author(s):  
James C. Parker
Keyword(s):  
Endothelial Cell ◽  
Safety Factor ◽  
Hydraulic Conductance ◽  
Safety Factors ◽  
Edema Formation ◽  
Exercise Induced ◽  
Permeability Studies ◽  
A Minor ◽  
Cell Phenotypes ◽  
Alveolar Capillary

Recent permeability studies comparing endothelial cell phenotypes derived from alveolar and extra-alveolar vessels have significant implications for interpreting the mechanisms of fluid homeostasis in the intact lung. These studies indicate that confluent monolayers of rat pulmonary microvascular endothelial cells had a hydraulic conductance ( Lp) that was only 5% and a transendothelial flux rate for 72-kDa dextran only 9% of values determined for rat pulmonary artery endothelial cell monolayers. On the basis of previous studies partitioning the filtration coefficients between alveolar and extra-alveolar vascular segments in rat lungs and previous studies of lymph albumin fluxes and permeability, the contribution of the alveolar capillary segment to total albumin flux in lymph was estimated to be less than 10%. In addition, the Starling safety factors against the edema calculated for the alveolar capillaries are quite different from those estimated for whole lung. Estimates of the edema safety factor due to increased filtration across the alveolar capillary wall based on the low Lp indicate it is quantitatively the greatest safety factor, although it would be a minor safety factor for extra-alveolar vessels. Also, a markedly higher effective protein osmotic absorptive force for plasma proteins must occur in the capillaries relative to extra-alveolar vessels. The lower Lp for alveolar capillaries also has implications for the sequence of hydrostatic edema formation, and it also may have a role in preventing exercise-induced alveolar flooding.

Factors Important in Determining the Heat Process Value, FT, for Low-Acid Canned Foods1

1987 ◽  
Vol 50 (6) ◽  
pp. 528-533 ◽  
Author(s):  
I. J. PFLUG
Keyword(s):  
Safety Factor ◽  
Clostridium Botulinum ◽  
Heat Processing ◽  
Processing Conditions ◽  
Safety Factors ◽  
Logarithmic Model ◽  
Heat Process ◽  
Canned Foods ◽  
Heat Preservation ◽  
Food Manufacturer

In this monograph an attempt is made to put into perspective several factors that impinge on the heat process value, FT. In the heat processing of low-acid canned foods (LACF), there are three specific types of final product spoilage that concern the food microbiologist and the food manufacturer. These three areas are discussed in some detail. The order to follow in the design of LACF and endpoint values are suggested. Use of descriptive and numerical terms for the endpoint of the LACF heat preservation process is discussed. The origin of the term, “commercial sterility,” is reviewed; reasons for replacing this term (in the future) with a specification are presented. The several faces of the widely-used heat process value, FT, are examined. The use of a safety factor to take care of unknown processing conditions is proposed. Suggested safety factors are listed. The classical research of Esty and Meyer on resistance of Clostridium botulinum is reviewed and interpreted using the simple logarithmic model. The often-quoted but poorly-understood term, 12D, is discussed.

Applying Partial Safety Factors in Mooring System Design

2005 ◽  
Author(s):  
Siril Okkenhaug ◽  
Bjo̸rn Sogstad ◽  
Jan Mathisen
Keyword(s):  
Safety Factor ◽  
Low Frequency ◽  
Offshore Structures ◽  
Mooring Line ◽  
Safety Factors ◽  
Safety Level ◽  
Partial Safety Factor ◽  
Account Due ◽  
Almost All ◽  
Partial Factor

The DNV offshore standard for position mooring, DNV-OS-E301 [1], was issued June 2001 based on the result from a joint industry project. A new revision was issued in October 2004. The consequences for mobile units when applying the new standard, compared to the old class rules, have been a major concern for operators of mobile units. A comparison study has therefore been initiated, where four relevant units are considered. We have applied the mooring design for existing mobile units that operate in Norwegian waters. Two different water depths are covered. The new standard, DNV-OS-E301, applies a partial safety factor format. However, the main difference when applying DNV-OS-E301 compared to the old POSMOOR [2] rules is that low frequency (LF) motions will have to be taken into account when calculating the line tensions. The results for the four mobile units are compared also to other relevant codes, i.e. the Draft International Standard ISO 19901-7 [4] and the present Norwegian regulations for offshore structures, NMD [5 & 6]. It should be noted that the present NMD regulations still do not require that LF motions are taken into account. Due to the partial safety factor format in DNV-OS-E301, more or less all of the units fulfill the requirements even though LF motion is accounted for. However, when comparing the results to the NMD regulations, the introduction of LF motion is crucial for almost all of the mobile units studied, as they have problems in fulfilling the requirements when this response is accounted for. Simply including LF motion in design would tend to increase the required strength of the resulting mooring line designs, and thereby raise the safety level if nothing else is done with the NMD regulations. Thus, provided that the present safety level for mobile units is sound, the present NMD safety factors could either be reduced or the partial factor format in DNV-OS-E301 could be adopted in order to maintain the safety level for mobile units when LF motion is taken into account.

Applied Taguchi Method for Fatigue Testing of Customized Hip Implant

2016 ◽  
Vol 39 (12) ◽  
pp. 611-618
Author(s):  
Mangesh R. Dharme ◽  
Abhaykumar M. Kuthe ◽  
Tushar R. Deshmukh
Keyword(s):  
Taguchi Method ◽  
Safety Factor ◽  
Fatigue Testing ◽  
Geometrical Parameters ◽  
Hip Implants ◽  
Safety Factors ◽  
Element Analysis ◽  
Hip Implant ◽  
Neck Shaft Angle ◽  
Minimum Number

Purpose Human activities generate stresses, which vary with time and may result in fatigue failure of the customized hip implant. This study aims to investigate fatigue testing of customized hip implants using the minimum number of experiments by the Taguchi method, for 147 patients. This study was also useful to determine the influential geometrical parameters on the fatigue safety factor of customized hip implants. Methods Horizontal offset (HO), vertical offset (VO) and neck shaft angle (NSA) of the hip joint of 147 patients were measured on computed tomography (CT) scanned images. Stress and strain of hip implants were calculated by finite element analysis and validated by in vitro experimental tests. Fatigue safety factors were calculated by Goodman, Soderberg and Gerber's fatigue theories and maximum stresses. Results Analysis of variance results show that the highest impact on fatigue safety factors was equal to 54.38% for HO, 16.33% for VO, and was equal to 29.16% for NSA with reference to Goodman, Soderberg and Gerber's fatigue theories. The hip implant shape of experiment no. 8 has the highest safety factor value compared to all other hip implants. Conclusions The results show that HO has the maximum influence on fatigue safety factors. The determination of influential geometric parameters may be useful to redesign customized hip implants in order to achieve the highest fatigue safety factor. The Taguchi method is suitable for fatigue testing of custom hip implant with a minimum number of experiments.

Fatigue Safety Factors for Deepwater Risers

2002 ◽  
Author(s):  
B. Stahl ◽  
H. Banon
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Safety Factor ◽  
Damage Index ◽  
Rational Approach ◽  
Fatigue Reliability ◽  
Safety Factors ◽  
Fatigue Design ◽  
Uncertainty Parameters ◽  
Deepwater Risers

Fatigue life is governed by a number of variables that are highly uncertain. The safety factor on fatigue life is used in a deterministic way to account for the estimated fatigue damage uncertainty. High uncertainties lead to high fatigue safety factors, and vice versa. Evaluation of the uncertainties in the variables governing fatigue design provides a grip on what the safety factor should be. This paper addresses riser fatigue using a fatigue reliability model that is relatively simple but still captures the important elements of the fatigue problem. The bias and uncertainty of stress range are extremely important parameters in design against fatigue. This is due not only to the fact that these parameters are highly uncertain, but also to the fact that they are greatly amplified in the fatigue damage equation by the ‘slope’ m of the S-N curve. The Palmgren-Miner fatigue damage index and the intercept value of the S-N curve are additional important variables in fatigue design. A model for combining wave-induced and vortex-induced vibration (VIV) is introduced together with the best available data and reference to industry work in this technology area. A recently completed joint industry project on riser reliability provides good calibration points for the critical fatigue reliability variables. Reliability and sensitivity studies are performed to demonstrate the effect of the uncertainty parameters. An approach to selecting deterministic fatigue design factors that yield specified reliability targets is developed and illustrated. The study provides a rational approach to selecting safety factors for design of deepwater risers, taking into account both wave and VIV-induced fatigue damage.

scholarly journals Probabilistic Assessment Approach of the Aerostatic Instability of Long-Span Symmetry Cable-Stayed Bridges

Symmetry ◽  
2021 ◽  
Vol 13 (12) ◽  
pp. 2413
Author(s):  
Fenghui Dong ◽  
Feng Shi ◽  
Libin Wang ◽  
Yang Wei ◽  
Kaiqi Zheng
Keyword(s):  
Finite Element ◽  
Safety Factor ◽  
Random Variables ◽  
Safety Analysis ◽  
Safety Factors ◽  
Long Span ◽  
Reliability Method ◽  
Sutong Bridge ◽  
Cable Stayed Bridges ◽  
Probabilistic Safety

The existing safety analysis methods for the assessment of the aerostatic stability of long-span symmetry cable-stayed bridges have difficulties in meeting the requirements of engineering applications. Based on the finite element method and the inverse reliability theory, an approach for the probabilistic safety analysis of the aerostatic instability of long-span symmetry cable-stayed bridges is proposed here. The probabilistic safety factor of aerostatic instability of long-span symmetry cable-stayed bridges was estimated using the proposed method, with Sutong Bridge as an example. The probabilistic safety factors for the aerostatic instability of Sutong Bridge were calculated using the finite element inverse reliability method, based on the FORM approach. The influences of the mean value and the coefficient of variation of random variables, as well as the iterative step length of finite difference, on the probabilistic safety factors of aerostatic instability of Sutong Bridge were analyzed. The results indicated that it is necessary to consider the uncertainties of random variables in probabilistic safety factor assessments of aerostatic instability in cable-stayed bridges using the proposed method, which could be recommended for the assessment of safety factors involved in the aerostatic instability of long-span symmetry cable-stayed bridges. The randomness of the parameters had an important influence on the probabilistic safety factor of the aerostatic stability of Sutong Bridge. Neglecting the randomness of these parameters may result in instability of the structure.

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