scholarly journals Selected Aspects Related to Preparation of Fatigue Tests of a Metallic Airframe

2014 ◽  
Vol 2014 (6) ◽  
pp. 95-101
Author(s):  
Józef Brzęczek ◽  
Jerzy Chodur ◽  
Janusz Pietruszka
Keyword(s):  
Control System ◽  
Service Life ◽  
Fatigue Tests ◽  
Landing Gear ◽  
Full Scale ◽  
Test Plan ◽  
Safe Life ◽  
Wing Load ◽  
Life Philosophy ◽  
Test Objects

AbstractThe basis for the computation of the service life of the PZL M28 was the results of the full-scale fatigue tests of the structure [1]. As the PZL M28 is a commuter category airplane according to the 14 CFR Part 23 and CS-23 regulations, the test objects were: (1) wing and wing load carry-through structure, (2) empennage and attached fuselage structure. Additionally, there were fatigue tests carried out for the landing gear and other selected elements including control system elements. The aircraft load carry-through structure is metallic and the cabin is unpressurized. The fatigue tests were conducted stage-by-stage. As the tests progressed, it was possible to extend the aircraft’s target service life, applying a safe life philosophy with reference to the primary components of the load carry-through structure.This paper brings into attention selected issues related to the fatigue tests preparation (the stage following the preparation of the test plan), with focus on the wing and wing load carry-through structure.

scholarly journals Selected Aspects Related to the Applied Loads Control During Fatigue Tests of a Metallic Airframe

2014 ◽  
Vol 2014 (6) ◽  
pp. 102-106
Author(s):  
Józef Brzęczek ◽  
Jerzy Chodur ◽  
Janusz Pietruszka
Keyword(s):  
Control System ◽  
Service Life ◽  
Fatigue Tests ◽  
Landing Gear ◽  
Full Scale ◽  
Safe Life ◽  
Wing Load ◽  
Life Philosophy ◽  
Test Objects

Abstract Service life of the PZL M28 is computed based on the results of the full-scale fatigue tests of the structure [1]. As the PZL M28 is a commuter category airplane according to the 14 CFR Part 23 and CS-23 regulations, the test objects are: (1) wing and wing load carry-through structure, (2) empennage and attached fuselage structure. Additionally, there are fatigue tests carried out for the landing gear and other selected elements including control system elements. The aircraft load carry-through structure is metallic and the cabin is unpressurized. The fatigue tests are conducted stage-by-stage. As tests progress, it is possible to extend the aircraft target service life, applying the safe life philosophy with reference to the primary components of the load carry-through structure. The article brings into attention the issue of the applied loads control in conducting fatigue tests of the metallic airframe.

scholarly journals Selected Aspects Related to Preparation of a Fatigue Test Plan of a Metallic Airframe

2014 ◽  
Vol 2014 (6) ◽  
pp. 88-94 ◽  
Author(s):  
Józef Brzęczek ◽  
Henryk Gruszecki ◽  
Leszek Pieróg ◽  
Janusz Pietruszka
Keyword(s):  
Control System ◽  
Service Life ◽  
Fatigue Test ◽  
Fatigue Tests ◽  
Landing Gear ◽  
Test Plan ◽  
Wing Load ◽  
Life Philosophy ◽  
Test Objects ◽  
Structure Test

Abstract Service life of the PZL M28 is computed based on the results of the full-scale fatigue tests of the structure [1]. As the PZL M28 is a commuter category airplane according to the 14 CFR Part 23 and CS-23 regulations, the test objects were: (1) wing and wing load carry-through structure, (2) empennage and attached fuselage structure. Additionally, there were fatigue tests carried out for the landing gear and other selected elements including control system elements. The aircraft load carry-through structure is metallic and the cabin is unpressurized. The fatigue tests were conducted stage-by-stage. As tests progressed, it was possible to extend the aircraft target service life, applying the safe-life philosophy with reference to the primary components of the load carry-through structure. The article brings into attention selected issues related to the fatigue tests plan preparation, with focus on wing and wing load carry-through structure test.

Energy savings potential of new aeration system: Full scale trials

2012 ◽  
Vol 7 (4) ◽  
Author(s):  
A. Lazić ◽  
V. Larsson ◽  
Å. Nordenborg
Keyword(s):  
Control System ◽  
Energy Consumption ◽  
Total Energy ◽  
Energy Savings ◽  
Treatment Plant ◽  
Full Scale ◽  
Total Energy Consumption ◽  
Aeration System ◽  
Fine Bubble ◽  
Aeration Control

The objective of this work is to decrease energy consumption of the aeration system at a mid-size conventional wastewater treatment plant in the south of Sweden where aeration consumes 44% of the total energy consumption of the plant. By designing an energy optimised aeration system (with aeration grids, blowers, controlling valves) and then operating it with a new aeration control system (dissolved oxygen cascade control and most open valve logic) one can save energy. The concept has been tested in full scale by comparing two treatment lines: a reference line (consisting of old fine bubble tube diffusers, old lobe blowers, simple DO control) with a test line (consisting of new Sanitaire Silver Series Low Pressure fine bubble diffusers, a new screw blower and the Flygt aeration control system). Energy savings with the new aeration system measured as Aeration Efficiency was 65%. Furthermore, 13% of the total energy consumption of the whole plant, or 21 000 €/year, could be saved when the tested line was operated with the new aeration system.

scholarly journals Robust force and displacement control of an active landing gear for vibration reduction at touchdown and during taxiing

2021 ◽  
Vol 3 (4) ◽  
Author(s):  
Mehran Pirooz ◽  
Seyed Hossein Mirmahdi ◽  
Ahmad Reza Khoogar
Keyword(s):  
Control System ◽  
Force Control ◽  
Direct Method ◽  
Landing Gear ◽  
Gear System ◽  
Displacement Control ◽  
Robust Nonlinear Control ◽  
Control Loops ◽  
Tire Force ◽  
The Mathematical Model

AbstractIn this paper, a new approach is proposed to control the dynamic response of a landing gear system subjected to runway force, both on heavy landing conditions and at the taxiing process. The mathematical model of the system is used in a way that covers nonlinear dynamics characteristics of landing gear and nonlinear/nonaffine property of the external actuator. The operation of the landing gear system and its components are described briefly. The desired control system includes two different interior loops for displacement and force control. The inner loop determines the actuator force and the outer loop performs the displacement control. A lumped uncertainty is considered in both displacement and force control loops that represent uncertainties including parametric errors, measurement noises, unmodeled dynamics, disturbance due to runway excitation, and other disturbances. The direct method of Lyapunov is utilized for asymptotic stability analysis of the robust nonlinear control system (RNCS). This system is simulated in MATLAB software and the performance of the proposed controller is analyzed exactly. Besides, the results are compared with a passive system and conventional PID control. The comparison indicates that RNCS works better and more precisely. This method can reduce vibrations at touchdown and taxiing and effectively overcome uncertainty and provide well aircraft handling by decreasing the changes in tire force.

A Reliability-Based Approach to Assess Fatigue Behaviour Based on Small Incomplete Data Sets

2008 ◽  
Vol 44-46 ◽  
pp. 871-878 ◽  
Author(s):  
Chu Yang Luo ◽  
Jun Jiang Xiong ◽  
R.A. Shenoi
Keyword(s):  
Incomplete Data ◽  
Standard Procedure ◽  
Fatigue Behaviour ◽  
Fatigue Tests ◽  
Small Sample ◽  
Data Sets ◽  
Safe Life ◽  
A New Technique ◽  
And Performance

This paper outlines a new technique to address the paucity of data in determining fatigue life and performance based on reliability concepts. Two new randomized models are presented for estimating the safe life and pS-N curve, by using the standard procedure for statistical analysis and dealing with small sample numbers of incomplete data. The confidence level formulations for the safe and p-S-N curve are also given. The concepts are then applied for the determination of the safe life and p-S-N curve. Two sets of fatigue tests for the safe life and p-S-N curve are conducted to validate the presented method, demonstrating the practical use of the proposed technique.

scholarly journals Optimal Surface Aeration Control in Full-Scale Oxidation Ditches through Energy Consumption Analysis

Water ◽  
2018 ◽  
Vol 10 (7) ◽  
pp. 945 ◽  
Author(s):  
Yong Qiu ◽  
Chi Zhang ◽  
Bing Li ◽  
Ji Li ◽  
Xiaoyuan Zhang ◽  
...  
Keyword(s):  
Control System ◽  
Energy Consumption ◽  
Rural Areas ◽  
Energy Model ◽  
Full Scale ◽  
Economic Feasibility ◽  
Model Parameters ◽  
Online Data ◽  
Improve Energy Efficiency ◽  
Aeration Control

Oxidation ditches are popularly used in rural areas and decentralized treatment facilities where energy deficiency is of concern. Aeration control technologies are well established for diffusion systems in order to improve energy efficiency, but there are still challenges in their application in oxidation ditches because surface aerators have unique characteristics with respect to oxygen transfer and energy consumption. In this paper, an integral energy model was proposed to include the energy, aeration, and fluidic effects of surface aerators, by which the energy for aeration of each aerator can be estimated using online data. Two types of rotating disks with different diameters (1800 mm and 1400 mm) were monitored in situ to estimate the model parameters. Furthermore, a feedforward–feedback loop control strategy was proposed using the concept of energy analysis and optimization. The simplified control system was implemented in a full-scale Orbal oxidation ditch, achieving an approximately 10% saving in full-process energy consumption. The cost–benefit analysis and carbon emission assessment confirmed the economic feasibility and environmental contribution of the control system. The energy model can help process designers and operators to better understand and optimally control the aeration process in oxidation ditches.

A Hybrid Supervised Deep Learning and Nonlinear Finite Element Framework for Efficient Fatigue Life Predictions of Rotary Shouldered Threaded Connections

2020 ◽  
Author(s):  
Fei Song ◽  
Ke Li
Keyword(s):  
Finite Element ◽  
Deep Learning ◽  
Fatigue Life ◽  
Learning Algorithm ◽  
Fatigue Tests ◽  
Full Scale ◽  
Remaining Useful Life ◽  
Nonlinear Finite Element ◽  
Threaded Connections ◽  
Life Predictions

Abstract In this paper, a hybrid computational framework that combines the state-of-the art machine learning algorithm (i.e., deep neural network) and nonlinear finite element analysis for efficient and accurate fatigue life prediction of rotary shouldered threaded connections is presented. Specifically, a large set of simulation data from nonlinear FEA, along with a small set of experimental data from full-scale fatigue tests, constitutes the dataset required for training and testing of a fast-loop predictive model that could cover most commonly used rotary shouldered connections. Feature engineering was first performed to explore the compressed feature space to be used to represent the data. An ensemble deep learning algorithm was then developed to learn the underlying pattern, and hyperparameter tuning techniques were employed to select the learning model that provides the best mapping, between the features and the fatigue strength of the connections. The resulting fatigue life predictions were found to agree favorably well with the experimental results from full-scale bending fatigue tests and field operational data. This newly developed hybrid modeling framework paves a new way to realtime predicting the remaining useful life of rotary shouldered threaded connections for prognostic health management of the drilling equipment.

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