scholarly journals Code Calibration of the Eurocodes

2021 ◽  
Vol 11 (12) ◽  
pp. 5474
Author(s):  
Tuomo Poutanen
Keyword(s):  
High Reliability ◽  
High Accuracy ◽  
Variable Load ◽  
Reliability Model ◽  
Safety Factors ◽  
Rounding Errors ◽  
Code Calibration ◽  
Load Factors ◽  
Characteristic Values

This article addresses the process to optimally select safety factors and characteristic values for the Eurocodes. Five amendments to the present codes are proposed: (1) The load factors are fixed, γG = γQ, by making the characteristic load of the variable load changeable, it simplifies the codes and lessens the calculation work. (2) Currently, the characteristic load of the variable load is the same for all variable loads. It creates excess safety and material waste for the variable loads with low variation. This deficiency can be avoided by applying the same amendment as above. (3) Various materials fit with different accuracy in the reliability model. This article explains two options to reduce this difficulty. (4) A method to avoid rounding errors in the safety factors is explained. (5) The current safety factors are usually set by minimizing the reliability indexes regarding the target when the obtained codes include considerable safe and unsafe design cases with the variability ratio (high reliability/low) of about 1.4. The proposed three code models match the target β50 = 3.2 with high accuracy, no unsafe design cases and insignificant safe design cases with the variability ratio 1.07, 1.03 and 1.04.

The Remote Monitoring System of Highway Slope Safety

2014 ◽  
Vol 687-691 ◽  
pp. 747-750
Author(s):  
Cheng Hao Han ◽  
Jun Ping Zhu ◽  
Hao Li ◽  
Xing Tong Wang
Keyword(s):  
Real Time ◽  
Monitoring System ◽  
Remote Monitoring ◽  
High Reliability ◽  
Field Work ◽  
High Accuracy ◽  
Real Time Monitoring ◽  
Remote Monitoring System ◽  
Anchor System ◽  
Slope Condition

As it is impossible to conduct real-time monitoring on slope condition of highways, a remote monitoring system has been specially designed. Making use of GPRS technology, Labview and solar power, the system has realized nobody monitor on slope anchor system, automatic collection of slope pressure and displacement data. It enjoys advantages such as high-accuracy, real-time monitoring and high-reliability. Among existing effective monitoring ways, massive man-power is needed for on-field work, but real-time monitoring is still left to be achieved.

Design-development of a variable load tension—compression creep testing machine

1986 ◽  
Vol 21 (1) ◽  
pp. 25-31
Author(s):  
C J Morrison ◽  
D R Hayhurst
Keyword(s):  
High Temperature ◽  
Testing Machine ◽  
High Accuracy ◽  
Gauge Length ◽  
Ball Screw ◽  
Variable Load ◽  
High Temperature Creep ◽  
Design Development ◽  
Dead Weight ◽  
Compression Creep

The design and development is described of a variable load tension-compression creep machine (±50 kN) which overcomes the disadvantages of servo-hydraulic and recirculating ball screw testing machines. The use of dead weight levers to apply specimen loads ensures the achievement of low running costs. Screwed end specimens are used with a 25.40 mm parallel sided gauge length and a diameter of 12.70 mm. It is shown that, provided modest rates of loading (0.4 kN/s) are used, high accuracy ‘through zero’ loadings can be achieved. The machine has been shown to operate satisfactorily for long periods under tension-compression high temperature creep.

Assessing the Target Reliability Index for Nuclear Piping

2016 ◽  
Author(s):  
Kleio Avrithi
Keyword(s):  
Reliability Index ◽  
Historical Data ◽  
Allowable Stress ◽  
Safety Factors ◽  
Code Calibration ◽  
Target Reliability Index ◽  
Consistent Manner ◽  
Factor Design ◽  
Load And Resistance Factor ◽  
Allowable Stress Design

Previous research developed Load and Resistance Factor Design (LRFD) equations for Class 2 and 3 nuclear piping for different reliability levels and load combinations. The LRFD equations consider separate safety factors for each load and for the strength of steel in opposition to the Allowable Stress Design (ASD) equations used in the ASME Boiler and Pressure Vessel (B&PV) Code, Section III, Div. 1, where only one safety factor is considered. In order to use the developed LRFD equations for the design of nuclear piping, specific reliability levels or else acceptable probabilities of failure need to be assigned to each Code equation. The paper discusses the available methods for evaluating the target reliability index, such as historical data of piping failures, expert-opinion elicitation, and Code calibration. Code calibration is the method of determining the existing level of reliability in the Code equations and assigning the same reliability to the developed LRFD equations in a consistent manner. Code Calibration is explained to be the more appropriate method of assigning reliability levels to the LRFD equations. The other methods can supplement the analysis results.

Comparative Research on Attitude Algorithm of the Multi-Rotor UAV Based on the Gyroscope

2014 ◽  
Vol 651-653 ◽  
pp. 668-671
Author(s):  
Xin Zhang ◽  
Lan Yu
Keyword(s):  
Comparative Research ◽  
High Reliability ◽  
Euler Angle ◽  
High Accuracy ◽  
Mems Gyroscope ◽  
Autonomous Flight ◽  
Attitude Angle ◽  
The Stability ◽  
Mean Square Errors ◽  
Angle Calculation

Obtaining the flight attitude of high accuracy, high reliability is a prerequisite for achieving the autonomous flight of the multi-rotor UAV. MEMS gyroscope can solve attitude angle individually. The paper adopts Euler angle and quaternion algorithms respectively to calculate attitude angle of the multi-rotor UAV. The flight experiment shows that the quaternion algorithm can guarantee the accuracy and the stability of the attitude angle calculation. The root-mean-square errors of the pinch roll and heading angles which are calculated by the quaternion algorithm are 2.947o, 3.606o and 9.769o, which can meet the demand for the autonomous flight of the multi-rotor UAV.

Partial Safety Factors and Characteristic Values for Combined Extreme Wind and Wave Load Effects

2005 ◽  
Vol 127 (2) ◽  
pp. 242-252 ◽  
Author(s):  
Niels Jacob Tarp-Johansen
Keyword(s):  
Probabilistic Approach ◽  
Offshore Wind ◽  
Design Rule ◽  
Storm Event ◽  
Wave Loads ◽  
Wave Load ◽  
Safety Factors ◽  
Characteristic Values ◽  
Rule Method ◽  
Definition Of

Background: The present paper regards the concerted action of wind and wave loads on offshore wind turbines in the extreme storm event. The load combination problem involves the definition of the characteristic loads and safety factors. In wind engineering and offshore engineering well established practices for the definition of characteristic values and safety factors for wind and wave loads separately exist. The aim is to investigate the possibility of making a simple merger of these existing practices into a possibly conservative design rule. Method of Approach: The paper applies a simplified probabilistic approach giving an understanding of how the merging can possibly be established and finally gives first guidance on the choice of characteristic values and safety factors. Results and conclusions: Under the assumptions made herein, it is made probable that a simple combination rule can be established.

Safety factors and limit states analysis in geotechnical engineering

1984 ◽  
Vol 21 (1) ◽  
pp. 1-7 ◽  
Author(s):  
G. G. Meyerhof
Keyword(s):  
Geotechnical Engineering ◽  
Stability Conditions ◽  
Safety Factors ◽  
Limit States ◽  
Resistance Factors ◽  
Performance Factors ◽  
Load Factors ◽  
Partial Safety Factors ◽  
And Performance ◽  
Earth Retaining Structures

This paper outlines the ultimate and serviceability limit states in geotechnical engineering analyses. The magnitude of customary total and suggested partial safety factors in earthworks, earth retaining structures, excavations, and foundations is discussed. On the basis of comparisons between these safety factors and using recommended load factors on various types of loading, including water pressures, common resistance factors on cohesion and friction of soils and performance factors can be established together with some additional modification factors for particular stability conditions. The serviceability limit states of foundations and structures are briefly discussed.

A Framework for Patient Safety: A Defense Nuclear Industry–Based High-Reliability Model

2013 ◽  
Vol 39 (5) ◽  
pp. 233-240 ◽  
Author(s):  
David J. Birnbach ◽  
Lisa F. Rosen ◽  
Lorena Williams ◽  
Maureen Fitzpatrick ◽  
David A. Lubarsky ◽  
...  
Keyword(s):  
Patient Safety ◽  
High Reliability ◽  
Nuclear Industry ◽  
Reliability Model

Bolt Load Changes Due to Internal Pressure in Gasketed Flange Connections

2003 ◽  
Author(s):  
Satoshi Nagata ◽  
Mitsuhiro Matsumoto ◽  
Toshiyuki Sawa
Keyword(s):  
Internal Pressure ◽  
Thrust Force ◽  
High Reliability ◽  
Constant Load ◽  
Point Of View ◽  
Load Factor ◽  
Test Results ◽  
Performance Point ◽  
Load Factors ◽  
Sealing Performance

Bolt load changes due to internal pressure are very important in order to evaluate the integrity of gasketed flange connections in the sealing performance point of view, because its gasket stress which dominates leak rate changes according to the bolt load changes. For establishing a connection possesses high reliability and sufficient integrity, it is necessary to clarify the mechanics ofgasketed flange connections. For this purpose, authors carried out experimental pressurizing tests for 3B and 20B gasketed flange connections clamped by various bolt preloads and measured the bolt load changes with increasing internal pressure up to 5MPa. Also a load factor, which is defined as the ratio of axial bolt force increment to pressure thrust force, was calculated using the test results. The test results indicate that 3B and 20B flange connections with the spiral wound gaskets have a constant load factors under sufficient initial clamping forces in assemble.

scholarly journals Multieffect Coupled Nanogenerators

Research ◽  
2020 ◽  
Vol 2020 ◽  
pp. 1-24
Author(s):  
Yun Ji ◽  
Yuan Liu ◽  
Ya Yang
Keyword(s):  
Electronic Device ◽  
High Reliability ◽  
High Accuracy ◽  
Charge Carriers ◽  
Energy Harvesters ◽  
Available Energy ◽  
Potential Applications ◽  
Self Powered ◽  
Output Characteristics ◽  
Device Interaction

With the advent of diverse electronics, the available energy may be light, thermal, and mechanical energies. Multieffect coupled nanogenerators (NGs) exhibit strong ability to harvest ambient energy by integrating various effects comprising piezoelectricity, pyroelectricity, thermoelectricity, optoelectricity, and triboelectricity into a standalone device. Interaction of multitype effects can promote energy harvesting and conversion by modulating charge carriers’ behaviour. Multieffect coupled NGs stand for a vital group of energy harvesters, supporting the advances of an electronic device and promoting the resolution of energy crisis. The matchless versatility and high reliability of multieffect coupled NGs make them main candidates for integration in complicated arrays of the electronic device. Multieffect coupled NGs can also be employed as a variety of self-powered sensors due to their rapid response, high accuracy, and high responsivity. This article reviews the latest achievements of multieffect coupled NGs. Fundamentals mainly including basic theory and materials of interest are covered. Advanced device design and output characteristics are introduced. Potential applications are described, and future development is discussed.

scholarly journals DEVELOPMENT OF A TECHNICAL SOLUTION OF THE KNOTTING ROOT SCRIPALS OF A SWITCHING TRANSMISSION

2019 ◽  
pp. 87-96
Author(s):  
V. S. SYDORENKO ◽  
YE. M. FEDORENKO ◽  
O. V. HUBAR ◽  
M. A. ARBUZOV ◽  
V. S. ANDRIEIEV
Keyword(s):  
High Reliability ◽  
High Accuracy ◽  
Climatic Conditions ◽  
Operating Conditions ◽  
Technical Solution ◽  
Lateral Direction ◽  
Straight Line ◽  
Current Content ◽  
Improved Design ◽  
Technical Solutions

Purpose. The article proposes a technical solution to the design of the root-fastening assembly of turnouts, which corresponds to the operating conditions of the railways. Methodology. To achieve the stated goal, the authors analyzed the existing designs of root binding of turnouts and formulated proposals that should be used when developing new technical solutions for root binding. The designs of root bonds should provide simplicity of construction, have a few number of parts, be repairable; allow to use of special devices for the mechanization of installation and dismantling works, have a few cost, provide high reliability. It must also to provide high accuracy along the width of the path. Structures should be able to control the width of the path to the standard indicators in the lateral direction, and if necessary (in a straight line). The designs of root bonds should be adapted for all climatic conditions of Ukraine. Findings. Proposals have been used in the development and improvement of technical solutions for root bonding. A root binding was developed which was called the root binding of the insert-nodule type P and an improved root binding was developed, the improved design was called the root binding of the insert-nodular type SD. The developed technical solutions for the design of root bonds meet the requirements, and with the current content of the switch, they solve the problem of the need to adjust the width of the path in the knit root node. Originality. It has been established that the technical solution of root fastening of the insert-overlay type of CD has advantages over the technical solution of root fastening of the insert-overlay type P since it has the ability to move the root of the wit by changing the position of the regulating element to the field side, thereby facilitating the current maintenance of the path. Practical value. Proposals were developed for regulating the width of the path using the regulating element of the root fastening of the liner-overlay type of CD, the proposals took into account the requirements for different operating conditions, namely for the main, receiving and other routes taking into account the corresponding tolerances for them, the corresponding schemes of the control plates are given.

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