The Influence of The Degree of the Rivet Hole Sizing on the Fatigue Life

• Autorzy: Lipski A.

Identyfikatory

DOI

10.2478/v10164-012-0057-2

• Języki publikacji: EN

Abstrakty

EN

The paper presents the results of fatigue tests of specimens with sized rivet holes. Samples for tests were made of 0.05'' (1.27 mm) thick non-clad plates of aluminium grade 2024-T3. Rivet holes were prepared assuming that they shall be used for 3 mm nominal diameter snap head rivets for aviation-related purposes. Different sizing degrees were achieved by drilling holes of different diameters in the samples followed by the sizing process using a sizing mandrel of the same diameter of 3.15 mm. Holes in the test samples were drilled using special device ensuring appropriate quality and repeatability of the holes. Five different sizing degrees were achieved be means of five drills of different diameters. Samples with holes of varying degrees of sizing were tested under constant amplitude sinusoidal loading conditions (cycle asymmetry coefficient R = 0) at the load frequency of 5 Hz. The study was conducted at three levels of maximum stress in the cycle. Fatigue life test results were presented in the form of fatigue diagrams (regression lines) determined in the bi-logarithmic coordinate system log N, log S_max. The results of the fatigue life tests received for the drilled as well as drilled and reamed holes were also presentedfor comparison. The results obtained lead to the conclusion that that the lowest fatigue life characterises samples with drilled holes and drilled and reamed holes. Fatigue life of specimens with holes for rivets improved (by 50% to 74%, depending on load level), even as a result of the hole surface polishing only (minimum sizing degree), whilst the two-fold growth of fatigue life was achieved for holes of a slight sizing degree. A further significant increase in fatigue life was achieved by the cold work of the hole's surface. Based on the location of the fatigue diagrams and the fatigue life tests results, it may be concluded that the higher a sizing degree, the higher the fatigue life growth. The growth is also proportional to the specimen load level: the lower the load level, the higher the fatigue life growth. Fatigue diagrams obtained from tests were divided into three groups: diagrams for drilled holes and drilled and reamed holes, diagrams for holes with a low degree of sizing and diagrams for holes with a high degree of sizing. This division was confirmed by statistical tests of regression lines parallelism by the “peer-to-peer” method.

Słowa kluczowe

EN

fatigue tests; rivets; holes; fatigue life

• Wydawca: Wydawnictwa Naukowe Sieci Badawczej Łukasiewicz - Instytutu Lotnictwa
• Czasopismo: Fatigue of Aircraft Structures
• Rocznik: 2012
• Tom: Iss. 4
• Strony: 64--69
• Opis fizyczny: Bibliogr. 4 poz., rys., tab., wykr., wzory

Twórcy

autor

Lipski A.

• University of Technology and Life Sciences in Bydgoszcz, Faculty of Mechanical Engineering, Bydgoszcz, Poland

Bibliografia

• [1] Larouche S. at all. (2001). Influence of Cold Working and Interference Fit on Fatigue Life of 7475-T7351 Aluminum Alloy Fastener Hole. Ed. J. Rouchon Cepadues. Design for Durability in the 21th Symposium of the International Committee on Aeronautical Fatigue, 27-29 June 2001 (pp. 681-698), Toulouse, France.
• [2] Lipski A., Mroziński S., Lis Z. (2011). Evaluation of the rivet hole sizing degree effect on the fatigue life, Journal of Polish CIMAC, Vol. 6(3), pp. 119-125.
• [3] Branch standard: Snap head rivet for aircraft. BN-70/1121-03 (in Polish).
• [4] Branch standard: Rivets for aviation-related purposes. Length selection, formed rivet heads dimensions and diameters of holes for rivets. BN-70/1120-03 (in Polish).

Uwagi

EN

This work was financed from the funds of the Polish Ministry of Science and Higher Education in the years 2006-2010 as the research project No. 61/EUR/2006/02.

PL

Opracowanie ze środków MNiSW w ramach umowy 812/P-DUN/2016 na działalność upowszechniającą naukę.