624.014.078.45

welded truss, strength and deformability of the truss, cyclic loads, fracture of the truss.

The paper determines the effect of operational cyclic loads on damage to welded trusses. A physical model of a 600x120 rectangular welded truss with parallel belts was developed for the study. The scheme of its basing and loading corresponds to the conditions for a real 12000x2400 truss. The physical model of a 600x120 truss was investigated under static and cyclic loads on the STM-100 test complex. Under cyclic loads, the fatigue crack nucleation site was identified, its propagation rate was determined, and the critical crack length at which the truss collapses was found. An analytical dependence has been developed to determine the dynamics of fatigue crack propagation during the operation of a truss under cyclic loads. Recommendations for the safe operation of a welded truss under cyclic loads, its strengthening and repair to increase the service life of the structure are formulated. Using the results of the work in engineering practice will help prevent accidental destruction of the truss during its operation.

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3. Basara M. A. Damage and destruction of K-shaped assemblies of flat welded trusses: PhD thesis for the degree of Doctor of Philosophy: 131 – Applied Mechanics. Ternopil, 2021. 142 p.
4. Basara M. A., Kovalchuk Y. O. Durability of K-shaped assemblies of welded trusses. Proceedings of the VI International Scientific and Technical Conference “Damage to materials during operation, methods of its diagnosis and prediction”, 24–27 September 2019. Ternopil, 2019. pp. 143–144.
5. Jiang T., Wu Q., Wang L., Huo L., Song G. Monitoring of Bolt Looseness-induced Damage in Steel Truss Arch Structure using Piezoceramic Transducers. IEEE Sens. J. 2018, 18, 6677–6685.
6. Kaveh A., Khayatazad M. Ray optimisation for size and shape optimisation of truss structures. Comput. Struct. 2013, 117, pp. 82–94.
7. Fenton M., McNally C., Byrne J., Hemberg E., McDermott J., O'Neill M. Automatic innovative truss design using grammatical evolution. Autom. Constr. 2014, 39, pp. 59–69.
8. Khademi F. Load Rating of Railway Bridges by Analysis and Testing; Dissertations & Theses-Gradworks; Illinois Institute of Technology: Chicago, IL, USA, 2015.
9. Shynhera N. Y., Kovalchuk Y. O. Pat. No. 40196 Ukraine, IPC G01N 3/00. Device for basing of welded trusses during tests for static and cyclic strength; applicant and patentee Ternopil State Technical University № 40196; application for 13.11.08 ; published 25.03.09, Bulletin No. 6.
10. Smyrnaios S., Iliopoulos A., Vayas I., Truss models for inelastic stability analysis and design of steel plate girders, Engineering Structures, 2015, 105, pp. 165–173.
11. Piątkowski M., Elastic lateral buckling of steel truss with imperfections, Materiały Budowlane, 2016, 8, pp. 82–83. [In Polish]
12. Kortiš J., Daniel L., Škarupa M., Ďuratný M. Experimental modal test of the laboratory model of steel truss structure. Civ. Environ. Eng. 2016, 12, pp. 116–121.
13. De Castro Lemonge A. C., Duarte G. R., Da Fonseca L. G. An algorithm inspired by bee colonies coupled to an adaptive penalty method for truss structural optimization problems. J. Braz. Soc. Mech. Sci. Eng. 2019, 41, pp. 1–19.
14. Azad S. K., Aminbakhsh S. High-dimensional optimization of large-scale steel truss structures using guided stochastic search. Structures, 2021, 33, pp. 1439–1456. 
15. Shved Y., Kovalchuk Y., Bodrova L., Kramar H., Shynhera N. Material consumption optimization of a welded rafter truss made of angle profiles. Procedia Structural Integrity, 2022, 36, pp. 10–16.

1. General principles of ensuring the reliability and structural safety of buildings, structures, building structures and foundations: DBN V.1.2.-14-2009. Kyiv, Derzhkomstroy of Ukraine, 2009.
2. Shynhera N. Y. Statistical model for determining the residual life of a typical welded truss under cyclic loads: PhD thesis for the degree of Cand: 01.05.02 – mathematical modelling and computational methods.Ternopil, 2012. 166 p.
3. Basara M. A. Damage and destruction of K-shaped assemblies of flat welded trusses: PhD thesis for the degree of Doctor of Philosophy: 131 – Applied Mechanics. Ternopil, 2021. 142 p.
4. Basara M. A., Kovalchuk Y. O. Durability of K-shaped assemblies of welded trusses. Proceedings of the VI International Scientific and Technical Conference “Damage to materials during operation, methods of its diagnosis and prediction”, 24–27 September 2019. Ternopil, 2019. pp. 143–144.
5. Jiang T., Wu Q., Wang L., Huo L., Song G. Monitoring of Bolt Looseness-induced Damage in Steel Truss Arch Structure using Piezoceramic Transducers. IEEE Sens. J. 2018, 18, 6677–6685.
6. Kaveh A., Khayatazad M. Ray optimisation for size and shape optimisation of truss structures. Comput. Struct. 2013, 117, pp. 82–94.
7. Fenton M., McNally C., Byrne J., Hemberg E., McDermott J., O'Neill M. Automatic innovative truss design using grammatical evolution. Autom. Constr. 2014, 39, pp. 59–69.
8. Khademi F. Load Rating of Railway Bridges by Analysis and Testing; Dissertations & Theses-Gradworks; Illinois Institute of Technology: Chicago, IL, USA, 2015.
9. Shynhera N. Y., Kovalchuk Y. O. Pat. No. 40196 Ukraine, IPC G01N 3/00. Device for basing of welded trusses during tests for static and cyclic strength; applicant and patentee Ternopil State Technical University № 40196; application for 13.11.08 ; published 25.03.09, Bulletin No. 6.
10. Smyrnaios S., Iliopoulos A., Vayas I., Truss models for inelastic stability analysis and design of steel plate girders, Engineering Structures, 2015, 105, pp. 165–173.
11. Piątkowski M., Elastic lateral buckling of steel truss with imperfections, Materiały Budowlane, 2016, 8, pp. 82–83. [In Polish]
12. Kortiš J., Daniel L., Škarupa M., Ďuratný M. Experimental modal test of the laboratory model of steel truss structure. Civ. Environ. Eng. 2016, 12, pp. 116–121.
13. De Castro Lemonge A. C., Duarte G. R., Da Fonseca L. G. An algorithm inspired by bee colonies coupled to an adaptive penalty method for truss structural optimization problems. J. Braz. Soc. Mech. Sci. Eng. 2019, 41, pp. 1–19.
14. Azad S. K., Aminbakhsh S. High-dimensional optimization of large-scale steel truss structures using guided stochastic search. Structures, 2021, 33, pp. 1439–1456. 
15. Shved Y., Kovalchuk Y., Bodrova L., Kramar H., Shynhera N. Material consumption optimization of a welded rafter truss made of angle profiles. Procedia Structural Integrity, 2022, 36, pp. 10–16.