A gradient-enhanced JH2 model for dynamic simulations of concrete structures

  • Concrete structures subjected to impact and blast loads experience complex failure mechanisms that are challenging to simulate accurately. Local constitutive models formulated using plasticity with softening are commonly used for this purpose. The softening behavior is typically represented by a scalar damage field, which scales the yield surface to capture the degradation of material strength. However, these local models often exhibit meshdependent results with localization of damage into a few cells. To address this limitation, this study combines a modified version of the Johnson-Holmquist (JH2) model with a gradientenhancement approach. The introduction of an inertia term into the additional PDE for the determination of the nonlocal equivalent plastic strain transforms it into a hyperbolic equation, enabling an efficient solution with an explicit dynamics solver. A one-dimensional benchmark simulation demonstrates the differences between the local and gradient-enhanced models.Concrete structures subjected to impact and blast loads experience complex failure mechanisms that are challenging to simulate accurately. Local constitutive models formulated using plasticity with softening are commonly used for this purpose. The softening behavior is typically represented by a scalar damage field, which scales the yield surface to capture the degradation of material strength. However, these local models often exhibit meshdependent results with localization of damage into a few cells. To address this limitation, this study combines a modified version of the Johnson-Holmquist (JH2) model with a gradientenhancement approach. The introduction of an inertia term into the additional PDE for the determination of the nonlocal equivalent plastic strain transforms it into a hyperbolic equation, enabling an efficient solution with an explicit dynamics solver. A one-dimensional benchmark simulation demonstrates the differences between the local and gradient-enhanced models. The local model shows severe damage localization and diminishing plastic energy dissipation with finer meshes. In contrast, the gradient-enhanced model distributes damage over multiple elements, though the plastic strain still localizes within a single element. Introducing strain hardening with respect to the local equivalent plastic strain resolves this issue, ensuring convergence of plastic energy and non-localizing plastic strain. These findings are extended and validated with two-dimensional simulations, showcasing the model’s practical relevance. Additionally, the impact of the added inertia term is analyzed in the context of dynamic strength enhancement, a critical characteristic of concrete under high strain rates. The proposed gradient-enhancement approach demonstrates improved numerical stability and mesh-independence compared to local models, making it a suitable tool for simulating concrete behavior under extreme loading conditions.zeige mehrzeige weniger

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Metadaten
Autor*innen:Sjard Mathis RosenbuschORCiD
Koautor*innen:Jörg F. UngerORCiD, Daniel BalzaniORCiD
Dokumenttyp:Vortrag
Veröffentlichungsform:Präsentation
Sprache:Englisch
Jahr der Erstveröffentlichung:2025
Organisationseinheit der BAM:7 Bauwerkssicherheit
7 Bauwerkssicherheit / 7.7 Modellierung und Simulation
DDC-Klassifikation:Technik, Medizin, angewandte Wissenschaften / Ingenieurwissenschaften / Ingenieurbau
Freie Schlagwörter:Concrete modelling; Explicit dynamics; Gradient-enhancement; High strain rate
Themenfelder/Aktivitätsfelder der BAM:Infrastruktur
Infrastruktur / Green Intelligent Building
Infrastruktur / Security
Veranstaltung:GAMM 2025
Veranstaltungsort:Posen, Poland
Beginndatum der Veranstaltung:07.04.2025
Verfügbarkeit des Dokuments:Datei im Netzwerk der BAM verfügbar ("Closed Access")
Datum der Freischaltung:07.11.2025
Referierte Publikation:Nein
Eingeladener Vortrag (wissenschaftliche Konferenzen):Nein
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