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Simulation of inelastic rubber material using a force field based FE approach
Published in Per-Erik Austrell, Leif Kari, Constitutive Models for Rubber IV, 2017
L. Nasdala, M. Kaliske, Y. Wei
ABSTRACT: Inelastic material behavior is the result of a continuous rearrangement of chemical and physical bonds. The atomic interactions can be described using force fields, which can be deduced from quantum-mechanical considerations or rather ab initio computations or even determined from measurements. In order to be able to use force fields in the framework of the finite element method, a special 4-node-element without rotational degrees of freedom is developed to which the interatomic equilibrium distances and angles can be given as intrinsic material parameters. In contrast to standard elements, it has the advantage that the coordinates of the initial configuration only has to be given approximately, i.e. the finite elements model automatically relaxes to the equilibrium configuration with the lowest energy level.
Numerical Methods for Modeling of Nanosystems
Published in Alexander V. Vakhrushev, Computational Multiscale Modeling of Multiphase Nanosystems, 2017
There are force fields built on the calculations of molecular systems with quantum-mechanical methods. The example of such field is MMFF. Force field CVFF comprises specifying contributions of anharmonicity and interactions of force field components. The field is parameterized for the calculations peptides and proteins. The field GROMOS is intended to model aqueous or non-polar solutions of proteins, nucleic acids, and sugars.
AI for Molecular Physics
Published in Volker Knecht, AI for Physics, 2023
QM-parameterized ML models for MD simulations are often denoted as machine learning force fields. In general, a force field is a mathematical function yielding interatomic forces for a given configuration. Force fields have been employed for MD simulations for decades.
Regularized ab initio molecular force fields for key biological molecules: melatonin and pyridoxal-5′-phosphate methylamine Shiff base (Vitamin B6)
Published in Inverse Problems in Science and Engineering, 2021
Gulnara M. Kuramshina, Igor V. Kochikov, Svetlana A. Sharapova
The idea of the force field arises when a molecule is considered as a mechanical system of nuclei while all the interactions due to the electrons are included in an effective potential function U(q1,q2, … ,qn) where {q1,q2, … ,qn} denote n = 3N−6 generalized coordinates describing mutual positions of N atomic nuclei of the molecule. Together with the nuclear masses, this function determines the most important properties of a molecule. As is well known (see, e.g. [1,2]), the equilibrium configuration of the molecule satisfies the relation where we define coordinates { q1, q2, … , qn} so that in the equilibrium configuration q1 = q2 = … = qn = 0, and the following expansion is valid: U0 is a certain constant. The force constants constitute a positive definite matrix F determining all the molecular characteristics related to the small vibrations. Mathematically, the concept of the force field may be obtained through the adiabatic theory of perturbations with the use of a small parameter related to the ratio of electron mass to the mass of nuclei [1,2]. In a certain approximation the nuclei may be treated as particles moving in the force field determined by the potential energy function (2).
New development of atomic layer deposition: processes, methods and applications
Published in Science and Technology of Advanced Materials, 2019
Peter Ozaveshe Oviroh, Rokhsareh Akbarzadeh, Dongqing Pan, Rigardt Alfred Maarten Coetzee, Tien-Chien Jen
Molecular dynamics (MD) is a numerical method that uses Newton’s equations of motion for computationally simulating the movements of atoms and molecules. The techniques depend on the description of the interaction of molecules-force field and are extensively used in chemistry, physics, biophysics and biochemistry. MD more often is about developing quantitative predictions of molecular shape, sizes, flexibilities, the interactions with other molecules, its behaviour under pressure, and the relative frequency of one state or conformation compared to the others [95]. Using Newton’s equation of motions, the simulation calculates the forces between the atoms at each time step and updates the positions of the atoms at the following time step [96]. High costs and difficult chemical management associated with ALD studies have made more researchers to conduct numerical modelling of the ALD process to understand and study the operation process. In modelling, further insight into the ALD process is gained, hence minimizing the precursors’ inputs and wastes and also reduces the potential environmental impacts in future industrial productions [97].
Thermostructural Characterization of Silicon Carbide Nanocomposite Materials via Molecular Dynamics Simulations
Published in Advanced Composite Materials, 2022
Jose M. Ortiz-Roldan, Francisco Montero-Chacón, Elena Garcia-Perez, Sofía Calero, A. Rabdel Ruiz-Salvador, Said Hamad
In order to get a high level of confidence about the predicted properties of the nanocomposites, the force fields are first validated with experimental and DFT data. We compared the behaviour of the five potentials against some mechanical and structural properties, which allows us to choose the force field that better describes the materials and employ it to predict the properties of the SiC nanocomposites.