Quantitative Decisions Relative to Structural Integrity

1980 ◽  
Vol 102 (1) ◽  
pp. 56-63 ◽  
Author(s):  
C. A. Rau ◽  
P. M. Besuner
Keyword(s):  
Failure Modes ◽  
Structural Integrity ◽  
Product Liability ◽  
Turbine Rotor ◽  
Recent Developments ◽  
Quantitative Basis ◽  
Strong Motivation ◽  
Definition Of ◽  
And Control ◽  
Liability Claims

The injury potential and increased cost of licensing, insurance premiums, product liability claims, and field repairs or recalls provide strong motivation to quantitatively evaluate and control the risk of various products. Risk analysis involves the definition of the probable failure modes and the assessment of failure probability, failure severity and the corresponding risks and costs. Basic concepts are reviewed and recent developments in methods to quantify the risk of structural failure when limited failure experience is available are presented. An example involving a turbine rotor is described which illustrates how the conventional and, new methods provide a quantitative basis for assessing structural integrity and risk and for making decisions regarding future operation, repair, or replacement.

Fracture mechanics in design and service: ‘living with defects’ - Statistical aspects of design: risk assessment and structural integrity

1981 ◽  
Vol 299 (1446) ◽  
pp. 111-130 ◽  
Keyword(s):  
Fracture Mechanics ◽  
Structural Reliability ◽  
Structural Integrity ◽  
Product Liability ◽  
Probabilistic Methods ◽  
Statistical Variations ◽  
Engineering Designs ◽  
Recent Developments ◽  
Quantitative Basis ◽  
And Control

Statistical variations in input parameters that affect structural reliability have historically been incorporated approximately in engineering designs by application of safety factors. Increased concerns over the injury potential and costs of licensing, insurance, field repairs or recalls, and product liability claims now demand more quantitative evaluation of possible flaws or unusual usage conditions that might result from statistical variations or uncertainties. This paper describes the basic concepts of probabilistic fracture mechanics that are used to assess and control risk. Recent developments in combined analysis methods are presented that utilize field experience data with probabilistic analysis to improve the accuracy of the structural integrity predictions. Several specific examples are described that illustrate how these probabilistic methods are used to assess risk and to provide a quantitative basis for establishing design, operation or maintenance allowables. These procedures, which realistically model the actual statistical variations that exist, can eliminate unnecessarily conservative approximations and often achieve improved reliability at reduced cost.

On-Line Monitoring and Warning of Important In-Service Pressure Equipment Based on Characteristic Safety Parameters

2017 ◽  
Author(s):  
Xuedong Chen ◽  
Tiecheng Yang ◽  
Zhichao Fan ◽  
Yunrong Lv
Keyword(s):  
Big Data ◽  
Real Time ◽  
Failure Mechanism ◽  
Failure Modes ◽  
Structural Integrity ◽  
Safety Margin ◽  
Measurement Monitoring ◽  
Safety Parameters ◽  
Safety Parameter ◽  
Definition Of

Characteristic safety parameter refers to the parameter that reflects the inherent safety margin of pressure equipments subjected to certain failure mechanism. It has three main characteristics. Firstly, it is sensitive to the change in failure mechanism. Secondly, the safety of pressure equipments can be guaranteed by controlling this parameter. Thirdly, it is easy to measure. By real-time monitoring of this characteristic safety parameter, the quantitative assessment of the structural integrity and furhter the diagnosis and warning on the safety of in-service pressure equipments can be realized. In this paper, the definition of characteristic safety parameter is given first for the pressure equipments subjected to several typical failure modes. After that, the selection principle, measurement technique and determination of its critical value, etc., are then introduced by analyzing typical examples. In combination with the technical concepts of the Internet of Things and Big-Data, some research suggestions are proposed with respect to the remote monitoring and diagnosis techniques based on the characteristic safety parameter, including the sensing measurement, monitoring and analysis of big data, real-time diagnosis and early warning of safety condition, etc.

administrasi ketatausahaan sekolah

2020 ◽  
Author(s):  
Isra Revenia
Keyword(s):  
Information Needs ◽  
Control Functions ◽  
Definition Of ◽  
The Right ◽  
And Control

This article is made to know the destinantion and the administrasi functions of the school in order to assist the leader of an organazation in making decisions and doing the right thing, recording of such statements in addition to the information needs also pertains to the function of accountabilitty and control functions. Administrative administration is the activity of recording for everything that happens in the organization to be used as information for leaders. While the definition of administration is all processing activities that start from collecting (receiving), recording, processing, duplicating, minimizing and storing all the information of correspondence needed by the organization. Administration is as an activity to determine everything that happens in the organization, to be used as material for information by the leadership, which includes all activities ranging from manufacturing, managing, structuring to all the preparation of information needed by the organization.

A STRATEGY FOR MONITORING THE IMPACTS OF COMBINED SEWER OVERFLOWS ON THE OHIO RIVER

1994 ◽  
Vol 30 (1) ◽  
pp. 167-175
Author(s):  
Alan H. Vicory ◽  
Peter A. Tennant
Keyword(s):  
National Policy ◽  
The United States ◽  
Ohio River ◽  
Combined Sewer Overflows ◽  
Treatment Technology ◽  
Design Storm ◽  
Combined Sewer ◽  
Sewer Overflows ◽  
Definition Of ◽  
And Control

With the attainment of secondary treatment by virtually all municipal discharges in the United States, control of water pollution from combined sewer overflows (CSOs) has assumed a high priority. Accordingly, a national strategy was issued in 1989 which, in 1993, was expanded into a national policy on CSO control. The national policy establishes as an objective the attainment of receiving water quality standards, rather than a design storm/treatment technology based approach. A significant percentage of the CSOs in the U.S. are located along the Ohio River. The states along the Ohio have decided to coordinate their CSO control efforts through the Ohio River Valley Water Sanitation Commission (ORSANCO). With the Commission assigned the responsibility of developing a monitoring approach which would allow the definition of CSO impacts on the Ohio, research by the Commission found that very little information existed on the monitoring and assessment of large rivers for the determination of CSO impacts. It was therefore necessary to develop a strategy for coordinated efforts by the states, the CSO dischargers, and ORSANCO to identify and apply appropriate monitoring approaches. A workshop was held in June 1993 to receive input from a variety of experts. Taking into account this input, a strategy has been developed which sets forth certain approaches and concepts to be considered in assessing CSO impacts. In addition, the strategy calls for frequent sharing of findings in order that the data collection efforts by the several agencies can be mutually supportive and lead to technically sound answers regarding CSO impacts and control needs.

Social Failure Modes in Technology and the Ethics of AI

2020 ◽  
pp. 441-461
Author(s):  
Jason Millar
Keyword(s):  
Engineering Design ◽  
Failure Modes ◽  
Design Practice ◽  
Detailed Understanding ◽  
Ethical Implications ◽  
The Social ◽  
Underlying Causes ◽  
Physical Defects ◽  
Definition Of

This chapter argues that, just as technological artefacts can break as a result of mechanical, electrical, or other physical defects not fully accounted for in their design, they can also break as a result of social defects not fully accounted for in their design. These failures resulting from social defects can be called social failures. The chapter then proposes a definition of social failure as well as a taxonomy of social failure modes—the underlying causes that lead to social failures. An explicit and detailed understanding of social failure modes, if properly applied in engineering design practice, could result in a fuller evaluation of the social and ethical implications of technology, either during the upstream design and engineering phases of a product, or after its release. Ideally, studying social failure modes will improve people’s ability to anticipate and reduce the rate or severity of undesirable social failures prior to releasing technology into the wild.

An LQ Approach to Active Control of Vibrations in Helicopters

1996 ◽  
Vol 118 (3) ◽  
pp. 482-488 ◽  
Author(s):  
Sergio Bittanti ◽  
Fabrizio Lorito ◽  
Silvia Strada
Keyword(s):  
Optimal Control ◽  
Active Control ◽  
Linear Quadratic ◽  
Control Effort ◽  
Vibration Effect ◽  
Suitable Definition ◽  
Lq Optimal Control ◽  
The One ◽  
Definition Of ◽  
And Control

In this paper, Linear Quadratic (LQ) optimal control concepts are applied for the active control of vibrations in helicopters. The study is based on an identified dynamic model of the rotor. The vibration effect is captured by suitably augmenting the state vector of the rotor model. Then, Kalman filtering concepts can be used to obtain a real-time estimate of the vibration, which is then fed back to form a suitable compensation signal. This design rationale is derived here starting from a rigorous problem position in an optimal control context. Among other things, this calls for a suitable definition of the performance index, of nonstandard type. The application of these ideas to a test helicopter, by means of computer simulations, shows good performances both in terms of disturbance rejection effectiveness and control effort limitation. The performance of the obtained controller is compared with the one achievable by the so called Higher Harmonic Control (HHC) approach, well known within the helicopter community.

scholarly journals Method for designing multi-input system identification signals using a compact time-frequency representation

2021 ◽  
Author(s):  
Mathias Stefan Roeser ◽  
Nicolas Fezans
Keyword(s):  
System Identification ◽  
Design Method ◽  
Flight Test ◽  
Compact Representation ◽  
Time Frequency ◽  
Stability And Control ◽  
Frequency Representation ◽  
Aerodynamic Parameters ◽  
Definition Of ◽  
And Control

AbstractA flight test campaign for system identification is a costly and time-consuming task. Models derived from wind tunnel experiments and CFD calculations must be validated and/or updated with flight data to match the real aircraft stability and control characteristics. Classical maneuvers for system identification are mostly one-surface-at-a-time inputs and need to be performed several times at each flight condition. Various methods for defining very rich multi-axis maneuvers, for instance based on multisine/sum of sines signals, already exist. A new design method based on the wavelet transform allowing the definition of multi-axis inputs in the time-frequency domain has been developed. The compact representation chosen allows the user to define fairly complex maneuvers with very few parameters. This method is demonstrated using simulated flight test data from a high-quality Airbus A320 dynamic model. System identification is then performed with this data, and the results show that aerodynamic parameters can still be accurately estimated from these fairly simple multi-axis maneuvers.

scholarly journals Physical modelling of failure in composites

2016 ◽  
Vol 374 (2071) ◽  
pp. 20150280 ◽  
Author(s):  
Ramesh Talreja
Keyword(s):  
Composite Materials ◽  
Failure Modes ◽  
Structural Integrity ◽  
Failure Mechanisms ◽  
Local Stress ◽  
Physical Modelling ◽  
Stress Fields ◽  
Systematic Analysis ◽  
Composite Failure ◽  
Failure Theories

Structural integrity of composite materials is governed by failure mechanisms that initiate at the scale of the microstructure. The local stress fields evolve with the progression of the failure mechanisms. Within the full span from initiation to criticality of the failure mechanisms, the governing length scales in a fibre-reinforced composite change from the fibre size to the characteristic fibre-architecture sizes, and eventually to a structural size, depending on the composite configuration and structural geometry as well as the imposed loading environment. Thus, a physical modelling of failure in composites must necessarily be of multi-scale nature, although not always with the same hierarchy for each failure mode. With this background, the paper examines the currently available main composite failure theories to assess their ability to capture the essential features of failure. A case is made for an alternative in the form of physical modelling and its skeleton is constructed based on physical observations and systematic analysis of the basic failure modes and associated stress fields and energy balances. This article is part of the themed issue ‘Multiscale modelling of the structural integrity of composite materials’.

scholarly journals Veterinary Parasitology – recent developments in immunology, epidemiology and control

Parasitology ◽  
2000 ◽  
Vol 120 (7) ◽  
pp. 1-1
Author(s):  
RICHARD J. MARTIN ◽  
HENK D. F. H. SCHALLIG ◽  
L. H. CHAPPELL
Keyword(s):  
Field Of Study ◽  
Veterinary Parasitology ◽  
Recent Developments ◽  
And Control

There have been important developments in the field of veterinary parasitology over the last few years. This symposium was called to collect individuals together, who have made significant contributions to their field of study, to present and summarize their work.I would like to pause for a moment before introducing the Symposium in this preface to comment on the sad loss of Professor Peter Nansen, a particularly eminent Danish scientist who developed our field of study. I, like many others, remember him with affection. He was a very helpful colleague and outstanding leader of the Danish Centre for Experimental Parasitology, Royal Veterinary and Agricultural University, Frederiksberg C. We are all saddened by his death and will continue to carry our memories of him with us.

Sign in / Sign up

Export Citation Format

Share Document