Piotr Reymer

Development of Load Spectrum for Full Scale Fatigue Test of a Trainer Aircraft

PZL-130 “Orlik” is a turbo-propeller engine trainer airplane, entirely designed and build in Poland. This plane is used in Polish Air Force mainly for primary training of polish military pilots.

Introduction of an Individual Aircraft Tracking Program for the Polish SU-22

Abstract The Su-22 fighter-bomber is a military aircraft used in the Polish Air Force (PLAF) since the mid 1980’s. By decision of the Ministry of National Defence Republic of Poland, the assumed service life for this type of aircraft was prolonged up to 3200 flight hours based on the Full Scale Fatigue Test (FSFT) results. The FSFT was conducted using the real load profile defined during the Operational Load Monitoring Program (OLM) and the 3200 hour service life was also based on this load profile. In order to assure safe operation of all the 18 Su-22 aircraft, the Individual Aircraft Tracking program was introduced. The program was based on the results of the FSFT as well as the analysis of the flight parameters recorded by the THETYS onboard flight recorder. In this paper, the authors present the methodology, assumed fatigue hypothesis and preliminary results of the IAT program for the Polish Su-22.

Simulating the fatigue crack in the PZL-130 TC-II aircraft structure

Within the following article authors present the methodology for estimating crack propagation within the PZL-130 TC-II trainer aircraft structure. The considered crack initiated in the starboard of the fuselage near the canopy lock mechanism mounting holes during the Full Scale Fatigue Test (FSFT) and was discovered during a Non Destructive Investigation (NDI). The main goal of the presented work was to determine the crack propagation curve taking into account the geometry of the damaged element as well as the adjacent structure, material properties and the actual load spectrum used during the FSFT. Obtained curve was used to estimate safe NDI intervals during operation. Authors present results only for the considered damage, however identical methodology was used for other nine Critical Points (CP) determined during the FSFT.

Full scale fatigue test of the Su-22 aircraft – Assumptions, process and preliminary conclusions

The following article describes the Full Scale Fatigue Test of the Su-22 UM3K fighter-bomber. The test was carried out due to the decision of the Polish Ministry of Defense to prolong the service life for this type of aircraft. Within the article authors present the main goals of the test as well as main assumptions and simplifications which had to be done due to time and cost limitations. Furthermore the preparation and progress of each stage is described. Final section includes selected results and final remarks.

The Definition of the Load Spectrum for SU-22 Fighter-Bomber Full Scale Fatigue Test

Abstract The Su-22 fighter-bomber is a military aircraft used in the Polish Air Force since the mid 1980’s. By the decision of the Polish Ministry of Defense the predicted service life for this type of aircraft will be extended to 3200 flight hours. Due to the fact that some aircraft were nearing the end of the service life guaranteed by the manufacturer, the actual service life, determined based on the flight profile in the Polish Air Force, had to be validated. Consequently, the Full Scale Fatigue Test (FSFT) had to be carried out in order to verify that the required service life was attainable. This article describes the process of preparation of the load spectra used in the Su-22 FSFT. Due to the fact that the Su-22 has a variable sweep wing the whole test was divided into three Stages (landing, flight and flap loads) carried out at different wing sweep angles (30°/45°/30°). The spectra were developed using the historical data gathered from Flight Data Recorders (FDR), strain signals acquired during the Operational Load Monitoring program (OLM) and aerodynamic calculations.

Simulating Crack Propagation of a Selected Structural Component of the PZL-130 Orlik TC-II Aircrafts

Abstract This paper presents the process of estimating crack propagation within a selected structural component of the PZL-130 Orlik TC-II using a numerical model. The model is based on technical drawings and measurements of the real structure. The proper definition of the geometry, including the location and size of the gap between elements, is significant for mesh generation. During the simulation process the gap is combined node by node. Each time, the strain energy release rate (G) is calculated. The stress intensity factor and geometry correction factor are defined for consecutive crack lengths, and used further on to estimate crack propagation.

The Concept of a Full Scale Fatigue Test of a Su-22 Fighter Bomber

Abstract This article presents a concept of the full scale fatigue test of a Su-22 fighter bomber. The authors define the general concept and goals of the test as well as the tasks to be accomplished in the preparation stage. The current work status is summarized and future tasks are defined.

Preliminary Verification of Selected Solutions for Crack Detection

Abstract Throughout its service life an aircraft is subjected to varying loads. Because of those periodically appearing stresses, undesirable and irreversible changes in structure may occur. As a consequence, cracks are formed, which reduce aircraft structural strength, significantly affecting structural integrity. For that reason, intensive research works are carried out around the world to develop innovative and reliable methods for detection of cracks initiation and propagation. This paper presents two methods of crack detection. One of them uses wireless polymer gages for determining deformation in a test region. The other one uses electrical, resistive ladder sensors for detection of cracks and their length determination.

Fatigue Life Estimation of the Tail Boom and Vertical Stabilizer of MI-24 Helicopter

Fatigue Life Estimation of the Tail Boom and Vertical Stabilizer of MI-24 Helicopter The aim of this work was to estimate fatigue life of the Mi-24 helicopter tail boom and vertical stabilizer sheathing. The analysis was based on a numerical model of the helicopter airframe crucial to obtain stress fields under defined loads and to estimate fatigue life. In order to do so, the load spectrum, specific for Polish army helicopters, was obtained by means of strain gauge measurements during a series of experimental flights. Data collected during flights was post-processed to create a characteristic ten hour spectrum that would statistically represent the flight profile for Polish Army Mi-24 helicopters. The third crucial element of the analysis was the safe S-N curve that was created on the basis of 2024-T3 aluminum S-N curve. Two factors were introduced in order to change the curve in a way that would guarantee a higher level of certainty that the outcome is not overrated. As a result of this analysis the total fatigue life was estimated including the list of critical locations in which fatigue damage is prone to occur. These regions are going to be carefully examined during scheduled inspections.