Mass transport is a fundamental process in living organisms, responsible for the delivery of oxygen, nutrients, and drugs from blood vessels to tissues, as well as the removal of waste products back to the vascular and lymphatic systems. This exchange occurs across various biological barriers, including blood vessel walls and cellular membranes, an...

By Vladimir Simić, Miljan Milošević, Bodan Milićević, E.J. Koay, Xuewu Liu, Antonio Martino, Rossana Terracciano, Carly Filgueira, Miloš Kojić

The extremely complex biological and biochemical processes are mainly treated by laboratory and clinical investigations. In recent decades, the application of computational modeling has become more important in research and applications in the medical sciences. Despite enormous efforts and achievements in this modeling, there is still a need for ne...

By Miloš Kojić, Miljan Milošević, Vladimir Simić, Bogdan Milićević

The paper presents the procedure of implicit stress integration for constitutive models for soil and rock. The theoretical basis of Mohr-Coulomb, Matsuoka-Nakai, Hoek-Brown and Hyperbolic soil constitutive models are presented. Stress integration was performed using the theory of incremental plasticity. The general procedure of implicit stress inte...

By Dragan Rakić, Miroslav Živković

This paper presents the integration of muscle fatigue modeling into the finite element solver PAK, based on an extended version of Hill’s phenomenological model. While traditional muscle models focus primarily on force generation, this study incorporates fatigue dynamics to provide a more realistic representation of muscle performance over ti...

By Boban Stojanović, Miloš Kojić, Srboljub Mijailovich

This paper describes software developed based on numerical implementation of algorithms for coupled acoustic – structure interaction. This class of problems implies coupling of the fluid domain, with sound wave propagation, and the domain of solid, which vibrates under the pressure caused by sound waves from the fluid domain. The physical beh...

By Velibor Isailović, Nenad Filipović, Milica Nikolić, Miloš Kojić

Huxley-type muscle models offer a physiologically grounded description of cardiac contraction but remain computationally prohibitive for large-scale, multi-scale simulations. This article reviews surrogate modeling strategies that alleviate these costs for ventricular biomechanics, with emphasis on data-driven (RNN/TCN/GRU) and physics-informed (PI...

By Bogdan Milićević, Miloš Ivanović, Boban Stojanović, Miljan Milošević, Miloš Kojić, Nenad Filipović

Wave acoustic equation is implemented and solved using finite element method in PAK solver to simulate propagation of sound waves, that cause oscillations of ear’s components, such as cochlea (part of inner ear). To simulate mechanical behaviour of cochlea, behaviour of fluid in chambers and behaviour of basilar membrane which separates them ...

By Milica Nikolić, Velibor Isailović, Nenad Filipović

X-ray angiography is one of the diagnostic procedures applied in clinical practice to analyze the state of patient-specific coronary arteries. During this examination a parameter called fractional flow reserve (FFR) is invasively measured to quantitatively assess the existence of potential stenosis and its significance. The software proposed in thi...

By Tijana Đukić, Ognjen Pavić, Lazar Dašić, Tijana Geroski, Nenad Filipović

In this paper, we give a short overview of the basic concept of stress integration for inelastic material models. This methodology was introduced by the author, initially for thermo-elasticplastic and creep deformation of metals, termed as ‘effective-stress-function’ (ESF), and then generalized to the ‘governing parameter method&r...

By Miloš Kojić

The paper presents various examples of the application of the PAK software and its modules for thermal, filtration, and stress–strain analysis of different complex engineering structures such as gravity dams, arch dams, embankment dams, tunnels, and mines. Examples of research, studies, and projects in which PAK has been applied to assess the...

By Dejan Divac, Slobodan Radovanović, Maja Pavić, Nikola Milivojević, Vladimir Milivojević, Miroslav Živković, Dragan Rakić, Snežana Vulović