A unified elasto-viscoplastic model for rate-dependent materials

Nagode, Marko (avtor), Šeruga, Domen (avtor), Oman, Simon (avtor), Klemenc, Jernej (avtor)

This paper presents a generalized elasto-viscoplasticity framework for modelling material behaviour under static, impact, and potentially cyclic loading. A theoretical equivalence between the classical Cowper–Symonds formulation and Chaboche’s viscoplasticity law is established, demonstrating that both can be expressed within a unified constitutive structure. Based on this equivalence, a new procedure is proposed for identifying elastoplastic and viscoplastic parameters directly from tensile, compressive, or strain-controlled tests performed at different strain rates. The method eliminates the need for additional creep or relaxation experiments and enables decomposition of the stress–strain response into elastoplastic and viscoplastic contributions. Several variants of the viscoplasticity law are introduced, each satisfying relevant physical constraints, and a regression-based strategy is employed for robust parameter identification. The framework is validated using four materially diverse datasets: X2CrNi18-9 stainless steel, Ti6Al4V titanium alloy, short glass fibre-reinforced polybutylene terephthalate (PBT), and hydroxyl-terminated polybutadiene (HTPB) propellant. In all cases, excellent agreement with experimental data is obtained. The proposed formulation further enables prediction of stress–strain behaviour at the limiting cases of zero and infinitely high strain rates, which cannot be accessed experimentally. The results demonstrate that a single constitutive law can capture rate-dependent responses across metals, polymers, and elastomers, making it suitable for structural analyses under monotonic loading, with potential extension to cyclic, multiaxial, and thermo-mechanical conditions.

• Jezik: Angleški jezik
• Ključne besede: viscoplasticity, strain rate effects, constitutive modelling, elasto-viscoplasticity modelling, finite element analysis, cowper–symonds and chaboche models
• Vrsta gradiva: Članek v reviji
• Tipologija: 1.01 - Izvirni znanstveni članek
• Organizacija: FS - Fakulteta za strojništvo
• Status publikacije: Objavljeno
• Različica publikacije: Objavljena publikacija
• Leto izida: 2026
• Št. strani: 15 str.
• Številčenje: Vol. 314, art. 111410
• PID: 20.500.12556/RUL-180870
• UDK: 544.236.4:519.6
• ISSN pri članku: 0020-7403
• DOI: 10.1016/j.ijmecsci.2026.111410
• COBISS.SI-ID: 272121603
• Datum objave v RUL: 18.03.2026

Gradivo je del revije

• Naslov: International journal of mechanical sciences
• Skrajšan naslov: Int. j. mech. sci.
• Založnik: Elsevier
• ISSN: 0020-7403
• COBISS.SI-ID: 25648384

Licence

• Licenca: CC BY 4.0, Creative Commons Priznanje avtorstva 4.0 Mednarodna
• Povezava: http://creativecommons.org/licenses/by/4.0/deed.sl
• Opis: To je standardna licenca Creative Commons, ki daje uporabnikom največ možnosti za nadaljnjo uporabo dela, pri čemer morajo navesti avtorja.

Sekundarni jezik

• Jezik: Slovenski jezik
• Ključne besede: viskoplastičnost, hitrost deformacij, konstitutivno modeliranje, analiza končnih elementov, model cowper–symonds, model chaboche

Projekti

• Financer: ARIS - Javna agencija za znanstvenoraziskovalno in inovacijsko dejavnost Republike Slovenije
• Številka projekta: P2-0182
• Naslov: Razvojna vrednotenja