scholarly journals Reliability and Lifetime Assessment of Glider Wing’s Composite Spar through Accelerated Fatigue Life Testing

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2310 ◽  
Author(s):  
Sebastian Marian Zaharia ◽  
Mihai Alin Pop ◽  
Răzvan Udroiu
Keyword(s):  
Sandwich Structures ◽  
High Reliability ◽  
Statistical Processing ◽  
Bending Test ◽  
Design Stage ◽  
Test Time ◽  
Glass Fiber Reinforced Plastic ◽  
Reliability Indicators ◽  
Inverse Power Law ◽  
Number Of Cycles

The evaluation of the reliability and the lifetime of aerospace components has become an important segment of the design stage. The aeronautical components are subjected to complex, rigorous tests and have a long test life. The main goal in the field of aviation is to have components with high reliability and quality and to meet the mandatory requirements and regulations. The spars are stiffening components positioned along the wing and which take up most of the load and are tested for fatigue over a long period of time. The spar which was analysed in this study has a sandwich structure with GFRP (glass fiber reinforced plastic) skin and foam core. In this paper, the performances in the static and dynamic conditions of the GFRP-foam sandwich structures cut out of the composite spar of a glider were analysed. Additionally, using accelerated techniques based on the three-point fatigue bending test, the main reliability indicators of the GFRP-foam sandwich structures were determined. Using the statistical processing of the experimental data and the Inverse Power Law–Weibull acceleration model, the mean number of cycles to failure, in normal testing conditions of the GFRP-foam specimens was determined, with a value of 102,814. Using the accelerated testing techniques of the GFRP-foam sandwich structures an important decrease of the test time (8.43 times) was obtained.

scholarly journals DETERMINATION OF THE TREND OF CHANGES OF RELIABILITY INDICATORS OF STATE AVIATION HELICOPTERS ACCORDING TO OPERATING DATA

2020 ◽  
pp. 17-27
Author(s):  
V. Golub ◽  
V. Bashynskyi ◽  
M. Zhdaniuk
Keyword(s):  
High Reliability ◽  
Statistical Processing ◽  
Armed Forces ◽  
Operational Reliability ◽  
Flight Safety ◽  
Aviation Accidents ◽  
Reliability Indicators ◽  
Equipment Reliability ◽  
Reliability Characteristics ◽  
Different Types

The most important characteristics of the processes efficiency in aircraft equipment technical operation are the operational reliability characteristics. High reliability of aviation equipment is the main condition for its readiness, efficiency and safety. The aircraft equipment reliability is its ability to perform specified functions, maintaining during some time the values of the established flight and technical and operational indicators within the specified limits, which correspond to the specified modes and conditions of use, maintenance, repair, storage and transportation. Despite the quick scientific and technological progress in aviation, the problem of flights safety has become extremely acute in the present time. Empirical data statistical processing is an urgent task in monitoring of the Ukrainian Armed Forces aircrafts operation and determining trends in maintenance and repair, areas of modernization of armaments and military equipment. The subject of the work is the analysis and system approach based on the developed estimation technique of aviation equipment reliability indicators. The results of determined helicopters and their functional systems reliability are presented. The trend and the main reasons for the change in reliability indicators for 2016-2019 are determined. The main purpose of reliability analysis is to determine the causal relationships between quantitative and qualitative reliability indicators and the level of flight safety that lead to aviation accidents. Statistical information in the form of fault records and reports, where the generalized operational data are sent by the State aviation units according to the methodical recommendations. Indicators analysis of operational reliability and flights safety for helicopters according to statistical data of failures, damages and incidents is done. Moreover, the trend and the main reasons for the helicopters reliability indicators changes for the period 2016-2019 are defined. The results of research are presented in the final tables, which show the average values of operational reliability, flight safety and the level of combat flight task for different types of helicopters in all specialties. The causes of malfunctions that affect the level of operational reliability, flight safety and non-fulfillment of the flight task on helicopters for the period 2015-2019 were taken into account. According to the statistics analysis of the malfunctions reported causes , it is determined that the total number of reported malfunctions on different types of helicopters in 2019 increased by 11.0% compared to 2018, compared to 2017 by 43.7%, compared to 2016 by 58.4%, compared to 2015 by 70.0%.

DEVELOPMENT OF RELIABILITY PROJECT ESTIMATION PROCEDURE CONSIDERING EFFECTS OF IONIZING RADIATION FOR ELECTRONIC EQUIPMENT

2019 ◽  
pp. 57-63
Author(s):  
M. A. Artyukhova ◽  
S. N. Polesskiy
Keyword(s):  
Ionizing Radiation ◽  
Radiation Resistance ◽  
Power Plants ◽  
Estimation Procedure ◽  
Reliability Estimation ◽  
Electronic Equipment ◽  
Design Stage ◽  
Space Systems ◽  
Reliability Indicators ◽  
Project Estimation

Human activity is often accompanied by exposure of ionizing radiation: the exploitation of space systems and power plants, research using isotopic sources, medicine. The development of electronic equipment is regulated by carrying out activities to ensure the required reliability and radiation resistance. However, the effect of ionizing radiation on reliability indicators is not taken into account properly, or is not taken into account at all, that sometimes leads to the loss of expensive equipment and even to human victims. The article discusses the methodology for carrying out an adequate estimate of the reliability considering the influence of external influencing factors, including ionizing radiation. The timeliness of decisions making to ensure the required reliability indicators is determined by the completeness of the reliability estimation at the design stage. Effort to ensure the reliability and durability of devices after the design stage is not economically viable. The completeness and adequacy of the estimation always depends on the interaction of specialists in different fields: designers, programmers, experts in the field of circuit design, electrical engineering and experts in the field of reliability and radiation resistance.

Effect of Core Thickness and Intermediate Layers on Mechanical Properties of Polypropylene Honeycomb Multi-Layer Sandwich Structures

2014 ◽  
Vol 59 (1) ◽  
pp. 11-16 ◽  
Author(s):  
J. Arbaoui ◽  
Y. Schmitt ◽  
J.-L. Pierrot ◽  
F.-X. Royer
Keyword(s):  
Mechanical Properties ◽  
Sandwich Structures ◽  
Bending Test ◽  
Honeycomb Core ◽  
Lightweight Construction ◽  
Specific Strength ◽  
High Specific Strength ◽  
Intermediate Layers ◽  
Core Thickness ◽  
Strength And Stiffness

Abstract Sandwich structures are widely used in lightweight construction especially in aerospace industries because of their high specific strength and stiffness. This paper investigates the effect of core thickness and intermediate layers on the mechanical properties of a polypropylene honeycomb core/composite facing multilayer sandwich structure under three points bending. We developed a theoretical model which makes it possible to calculate the shear properties in multi-cores. The results obtained by this model are agreed with our experimental results, and the results obtained with bending test showed that the mechanical properties of the composite multilayer structures increase with core thickness and intermediate layers.

Evaluating children’s websites from an information visualization perspective: findings of a comparative mixed-methods study

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yaghoub Norouzi ◽  
Hamid Keshavarz ◽  
Zahra Jafari Athar
Keyword(s):  
Mixed Methods ◽  
Conceptual Model ◽  
Information Visualization ◽  
Interface Design ◽  
Evaluation Method ◽  
High Reliability ◽  
Comparative Approach ◽  
Extensive Literature ◽  
Content Type ◽  
Reliability Indicators

Purpose This study aims to evaluate the selected children’s websites in terms of information visualization features based on the criteria existing in the related literature and expert scrutiny. Design/methodology/approach A mixed-methods (qualitative-quantitative) study was conducted with a descriptive-comparative approach. A set of 80 English websites, as well as 24 quality Persian websites, were selected constituting a sample size of 104 websites. A conceptual model was developed from an extensive literature review on information visualization in children’s websites. In the quantitative part, a checklist derived from the conceptual model and based on the heuristic evaluation method was distributed among 20 related experts, the data of which were then analysed through Partial Least Squares using SmartPLS 3.0. Findings Confirmatory factor analysis showed high-reliability indicators and fit indices in measurement and structural models showing that the conceptual model had the necessary validities among the expert evaluators. Path coefficients showed that layout design and user interface design were the first and last priorities among the dimensions. It was also found that English websites were much more successful than Persian websites in supporting the features of information visualization. Originality/value The current study has implications for the effective use of standard features related to information visualization in children’s websites usable for designers, media specialists, parents, instructors and librarians, which would also make the children more engaged to better use, learn and interact with the websites.

scholarly journals Research on the Weld Position Detection Method for Sandwich Structures from Face-Panel Side Based on Backscattered X-ray

Sensors ◽  
2019 ◽  
Vol 19 (14) ◽  
pp. 3198 ◽  
Author(s):  
Angang Wei ◽  
Baohua Chang ◽  
Boce Xue ◽  
Guodong Peng ◽  
Dong Du ◽  
...  
Keyword(s):  
Detection Method ◽  
Sandwich Structures ◽  
Detection System ◽  
High Reliability ◽  
Sandwich Panels ◽  
Experimental System ◽  
Maximum Absolute Error ◽  
X Ray ◽  
Position Detection ◽  
The Face

Web-core sandwich panels are a typical lightweight structure utilized in a variety of fields, such as naval, aviation, aerospace, etc. Welding is considered as an effective process to join the face panel to the core panel from the face panel side. However, it is difficult to locate the joint position (i.e., the position of core panel) due to the shielding of the face panel. This paper studies a weld position detection method based on X-ray from the face panel side for aluminum web-core sandwich panels used in aviation and naval structures. First, an experimental system was designed for weld position detection, able to quickly acquire the X-ray intensity signal backscattered by the specimen. An effective signal processing method was developed to accurately extract the characteristic value of X-ray intensity signals representing the center of the joint. Secondly, an analytical model was established to calculate and optimize the detection parameters required for detection of the weld position of a given specimen by analyzing the relationship between the backscattered X-ray intensity signal detected by the detector and the parameters of the detection system and specimen during the detection process. Finally, several experiments were carried out on a 6061 aluminum alloy specimen with a thickness of 3 mm. The experimental results demonstrate that the maximum absolute error of the detection was 0.340 mm, which is sufficiently accurate for locating the position of the joint. This paper aims to provide the technical basis for the automatic tracking of weld joints from the face panel side, required for the high-reliability manufacturing of curved sandwich structures.

Assessment of Products Future Reusability Based on Consumers Usage Behavior: Implications for Lithium-Ion Laptop Batteries

2015 ◽  
Author(s):  
Mostafa Sabbaghi ◽  
Behzad Esmaeilian ◽  
Ardeshir Raihanian Mashhadi ◽  
Willie Cade ◽  
Sara Behdad
Keyword(s):  
High Reliability ◽  
Lithium Ion ◽  
Degradation Process ◽  
Rechargeable Batteries ◽  
Data Set ◽  
Utilization Behavior ◽  
Product Reuse ◽  
Number Of Cycles ◽  
Stability Time ◽  
Product Durability

Product reuse is a recommended action toward sustainability. However, the profitable reusability of End-of-Use or End-of-Life (EoU/L) products depends on how consumers have used them over the initial lifecycles and what are their EoU conditions. In addition to consumers’ behavior, product design features such as product durability has an impact on the future reusability. In this paper, a data set of Lithium-ion laptop batteries has been studied with the aim of investigating the potential reusability of laptop batteries. This type of rechargeable batteries is popular due to their energy efficiency and high reliability. Therefore, understanding the lifetime of these batteries and improving the recycling process is becoming important. In this paper, the reusability assessment is linked to the consumer behavior and degradation process simultaneously through monitoring the performance of batteries over their lifetimes. After capturing the utilization behavior, the performance-based stability time of batteries is approximately derived. Consequently, the Reusability Likelihood of batteries is quantified using the number of cycles that the battery can be charged with the aim of facilitating future remarketing and recovery opportunities.

1.2 Computers and Their Potential: Software

1981 ◽  
Vol 5 ◽  
pp. 5-8
Author(s):  
Pamela A. Geisler ◽  
J. France
Keyword(s):  
High Reliability ◽  
Computer Hardware ◽  
Design Stage ◽  
Final Phase ◽  
Implementation Phase ◽  
Storage Media ◽  
Systems Software ◽  
And Performance ◽  
High Level

At the present time, with the high reliability and performance of computer hardware, computer systems applied in any field must be judged more by the quality of the software provided. Thus it is highly relevant in an investigation of the use of computers in a field such as animal production, to concentrate on aspects of the software.Software provides the computer with the ability to obey instructions and to do as the user wishes. However, before arriving at these ‘machine instructions’ a number of steps have to be covered. First, it is essential to design the software — that is, to establish the requirements to be achieved on the computer. This design stage is followed by the implementation phase, in which the requirements as stated in English are transformed into such instructions as the machine can read and obey. The final phase is testing, in which it must be determined whether the requirements have been met, and to modify the design and iterate until the performance is satisfactory.Software in general can be divided into three classes — systems, utility and applications software. The systems software drives the machine and its associated peripherals such as a VDU and printer. The systems software also includes a file system for organization of the data on the relevant storage media (floppy disks, cartridges, magnetic tape). Also considered part of the systems software are the assembler, interpreters and compilers for high level languages such as BASIC and FORTRAN and for programming aids such as DEBUGGERS. Systems software is normally supplied with the computer and needs to be evaluated along with the hardware by any prospective purchaser of a computer system.

Technological Principles for the Formation of Instrument Structures with Reproducible Parameters

2020 ◽  
Vol 22 (9) ◽  
pp. 489-492
Author(s):  
M.G. Mustafaev ◽  
◽  
G.A. Mustafaev ◽  
D.G. Mustafaeva ◽  
◽  
...  
Keyword(s):  
Production Process ◽  
Technological Process ◽  
Failure Mechanisms ◽  
Statistical Processing ◽  
Dielectric Strength ◽  
Design Stage ◽  
Statistical Relationships ◽  
Materials Used ◽  
The Stability ◽  
The Relationship

It is shown that increasing the role of control methods, identifying patterns and accuracy of performing technological operations, establishing the relationship between the characteristics of the technological process and the yield of suitable products, will ensure the reproducibility of technology and the formation of instrument structures with specified parameters. In the technological process of production, instrument structures are formed and constructive and technological foundations are implemented, on which the specified parameters are established in technological and final tests. Providing the specified parameters of device structures, depending on the production processes, is carried out on the basis of increasing the dielectric strength of oxide layers, improving the production process, and reducing the number of defects in oxide films. Improving the cleanliness during the production process allows you to reduce the level of defective structures. The inconsistency of the coefficients of thermal expansion of the materials used is the cause of failures of elements of integral electronics and a decrease in their reliability. Analysis of thermal effects and associated mechanical loads allows one to assess the optimality of the selected materials and to clarify the likely failure mechanisms. Knowledge of the failure mechanisms makes it possible to calculate the reliability of the device at the design stage, as well as to predict the reliability of the equipment being developed. The reproducibility of the technology is ensured by conducting a statistical analysis of the technological process, containing statistical processing, establishing statistical relationships between parameters, determining the regularities of the technological process, constructing regression models for the relationship between the yield of good products and modes of technological operations, and analyzing the stability of the technological process. The traceability of the relationship between the parameters of instrument structures and the technology of their manufacture allows to reduce the level of their defectiveness, statistical regulation, based on the measured values of the parameters, and determining their position relative to the regulation limits, ensures the accuracy of the production process.

A Review of Reliability Principles in Conceptual Design

2011 ◽  
Vol 199-200 ◽  
pp. 583-586
Author(s):  
Yu Lian Cui ◽  
Wei Wu
Keyword(s):  
Conceptual Design ◽  
High Reliability ◽  
Reliability Prediction ◽  
Design Stage ◽  
Design Phase ◽  
Product Reliability ◽  
Design Decisions ◽  
Early Stages ◽  
Conceptual Design Phase

In this paper an attempt has been made to identify certain useful parts that will assist to consider reliability during conceptual design phase. The aim is to provide some thoughts and a toolkit for addressing reliability during the early stages of design, influencing design decisions and product reliability, and reducing the relying on the reliability prediction and expensive experiments in later design stage. Therefore high reliability can be cost-effectively achieved.

Parametric study on factors influencing the stiffness of honeycomb sandwich panels using impulse excitation technique

2017 ◽  
Vol 21 (1) ◽  
pp. 115-134 ◽  
Author(s):  
M Phani Surya Kiran ◽  
I Balasundar ◽  
K Gopinath ◽  
T Raghu
Keyword(s):  
Thermal Protection ◽  
Sandwich Panels ◽  
Bending Stiffness ◽  
Bending Test ◽  
Design Stage ◽  
Design Parameters ◽  
Thermal Protection Systems ◽  
Honeycomb Sandwich ◽  
Protection Systems ◽  
Impulse Excitation

Metallic thermal protection systems are used to protect the airframe and pay load from aerodynamic and aerothermal heating in hypersonic cruise vehicles that are powered with advanced scramjet engines. Metallic thermal protection systems is a composite structure that contains honeycomb sandwich panels at the top and bottom and a variety of thermal insulating materials placed in between them. Several design factors influence the structural and thermal performance of the honeycomb sandwich panels. Panel bending stiffness is one important structural property that is generally estimated using a destructive 3-point or 4-point bending test. In this study, a numerical model based on the impulse excitation nondestructive evaluation technique has been developed to estimate the effect of various design parameters that affect the bending stiffness of the honeycomb sandwich panels. The results obtained are analyzed using standard statistical procedures. A major advantage of this method lies in evaluating the panel stiffness at the design stage without resorting to actual fabrication of the panels for destructive testing.

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