PSI - Issue 48

Available online at www.sciencedirect.com Available online at www.sciencedirect.com ScienceDirect Structural Integrity Procedia 00 (2023) 000–000

www.elsevier.com/locate/procedia

ScienceDirect

Procedia Structural Integrity 48 (2023) 19–26

Second International Symposium on Risk Analysis and Safety of Complex Structures and Components (IRAS 2023)

Fatigue Lifetime of a Howitzer Cannon Gašper Fašun a , Mirco D. Chapetti b , Nenad Gubeljak c*

a SIJ Ravne Systems d.o.o., Koroška c. 14, SI-2390 Ravne na Koroškem, Slovenia b Laboratory of Experimental Mechanics, INTEMA, CONICET - University of Mar del Plata. Av. Colón 10.850, (7600) Mar del Plata, Argentina c Faculty of Mechanical Engineering, University of Maribor, Smetanova ul. 17, 2000 Maribor, Slovenia

© 2023 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the IRAS 2023 organizers The approach allows quantifying the influence of different variables on the fatigue resistance and life of the barrel, enabling the estimation of safe operating conditions and the identification of an unsafe condition. The analysis provides valuable insights into enhancing the fatigue resistance of the barrel material, such as improving the fatigue threshold for long cracks to increase the critical crack length for a given maximum pressure. Addressing this issue could enhance the durability of the barrel and ensure better performance over an extended period of use. © 2023 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the IRAS 2023 organizers Keywords: howitzer; cannon barrel; estimation; lifetime; fatigue resistance; fracture mechanics 1. Introduction The high-strength steel 35NiCrMoV12-5 is ideal for structures that face heavy loads, such as howitzer cannon barrels, which are towed weapons used to support tactical units, with a firing range of up to 39 km and a rate of fire of up to three missiles per minute. To ensure safe and optimal operation, careful material selection and heat treatment are critical. 2 Fašun et al/ Structural Integrity Procedia 00 (2023) 000–000 Abstract This This work investigates the fatigue integrity of a barrel made of KATO1 alloy (35NiCrMoV12-5) with two different heat treatments, using a fracture mechanics approach based on fatigue resistance curve concepts. The analysis includes experimental and theoretical estimation of various necessary variables, such as microstructural size, static strength, fracture toughness, fatigue threshold for long and short cracks, and fatigue crack propagation properties. The thermographic method is used to experimentally estimate the fatigue limit of the two materials.

* Corresponding author.

E-mail address: nenad.gubeljak@uni-mb.si

The main input parameter in the lifetime analysis is certainly the pressure created by the combustio explosive acting on the inner wall of the cannon barrel. In this paper, the maximum values of press commonly found in the literature for cannon barrels of similar geometries are used. In the analysis of the li the classic cannon barrel we can find the pressure value of 380 MPa [1,2]. Experimental measurements container for testing howitzer barrel pressure showed maximum pressure of 420 MPa for barrel with inner 155 mm [3]. In the analysis of the exit pressure of a howitzer muzzle with the same diameter, a maximum 377 MPa has been measured [4]. In the analysis of simulation of artillery chambers [5], a pressure of 322 barrels with a diameter of 130 mm is mentioned. Besides, for a howitzer of the same dimensions a pressu MPa was found [6]. The distribution of pressure in barrel, p(x), whose value depends on position summarized according to [7]. Based on the pressure distribution p(x), the location of the samples w maximum pressure pmax is experimented can be determined for further analyses. Fig. 1 shows the cann geometry, the pressure distribution along the barrel and a cross section with schemas of all the specimens the experimental characterization of the material, and their localization and orientations.

2452-3216 © 2023 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the IRAS 2023 organizers

2452-3216 © 2023 The Authors. Published by ELSEVIER B.V. This is an open access article under the CC BY-NC-ND license (https://creativecommons.org/licenses/by-nc-nd/4.0) Peer-review under responsibility of the IRAS 2023 organizers 10.1016/j.prostr.2023.07.105