EFFECTS OF STOICHIOMETRY ON PROPERTIES OF DGEBF/DETDA EPOXY USING MOLECULAR DYNAMICS

2021 ◽  
Author(s):  
SAGAR PATIL ◽  
MICHAEL OLAYA ◽  
PRATHAMESH DESHPANDE ◽  
MARIANNA MAIARÙ ◽  
GREGORY ODEGARD
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Molecular Modeling ◽  
Bulk Modulus ◽  
Mass Density ◽  
Strong Dependence ◽  
Crosslinking Density ◽  
Mechanical Deformation ◽  
Epoxy System ◽  
Reactive Interface

This article details the molecular modeling of full and off-stoichiometry models of the DGEBF/DETDA epoxy system using Molecular Dynamics to predict the mechanical properties as a function of the crosslinking density. The Reactive Interface Force Field (IFF-R) is implemented in this work to simulate mechanical deformation. The “fix bond/react” command in LAMMPS is used to simulate crosslinking between epoxy monomers. The results show that the predicted mass density, volumetric shrinkage, and bulk modulus have a strong dependence on the stoichiometry of the epoxy.

MOLECULAR DYNAMICS SIMULATION OF POLYBENZOXAZINE RESIN FOR PROCESS MODELING

2021 ◽  
Author(s):  
PRASHIK S. GAIKWAD ◽  
AARON S. KRIEG ◽  
JULIA A. KING ◽  
MARIANNA MAIARU ◽  
GREGORY M. ODEGARD
Keyword(s):  
Molecular Dynamics ◽  
Process Modeling ◽  
Mass Density ◽  
Md Simulations ◽  
Crosslinking Density ◽  
Dynamics Simulation ◽  
Molecular Models ◽  
Gelation Point ◽  
Reactive Interface ◽  
Good Agreement

In this work, Molecular Dynamics (MD) simulations are performed to predict the physical properties (gelation point, mass density, volumetric shrinkage) and mechanical properties (Bulk modulus, Shear modulus, Young’s Modulus, Poisson’s ratio) of a PolyBenzoxazine (PBZ) resin system as a function of crosslinking density. The molecular models are developed using the Reactive Interface Force Field (IFF-R). The results obtained from MD are in good agreement with the experimental data.

MECHANICAL PROPERTIES PREDICTION OF PHENOLIC RESIN: A MOLECULAR DYNAMICS STUDY

2021 ◽  
Author(s):  
IVAN GALLEGOS ◽  
JOSHUA KEMPPAINEN ◽  
SAGAR U. PATIL ◽  
PRATHAMESH DESHPANDE ◽  
JACOB GISSINER ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Phenolic Resin ◽  
Mass Density ◽  
Carbon Composites ◽  
Mechanical And Thermal Properties ◽  
Phenolic Resins ◽  
Suitable Candidate ◽  
Mechanical Properties Prediction ◽  
Experimental Values

Carbon-carbon composites (CCCs) widely used in the aerospace and automotive industries due to their excellent mechanical and thermal properties. Phenolic resins have a relatively high carbon yield, which makes them a suitable candidate for CCCs manufacturing. Molecular Dynamics (MD) can further reduce costs by predicting properties of a material before manufacturing and testing. In the present work, a Molecular Dynamics (MD) model of a crosslinked phenolic resin was developed to predict mechanical properties by implementing the fix bond/react algorithm in LAMMPS. The predicted mass density (ρ) and Young’s Modulus (E) agree well with experimental values and highlights the validity of the topologybased approach to building stable molecular models of phenolic resins.

Effect of Size on the Mechanical Properties of Rh-20at%Pd Nanowire

2011 ◽  
Vol 403-408 ◽  
pp. 1173-1177
Author(s):  
Jamal Davoodi ◽  
Mohammad Javad Moradi
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Bulk Modulus ◽  
Elastic Constants ◽  
Constant Pressure ◽  
Young Modulus ◽  
Dynamics Simulation ◽  
Many Body ◽  
Temperature Constant ◽  
Body Potential

The aim of this research was to calculate Yong modulus, Bulk modulus and the elastic constants of Rh-20at%Pd (atom percent) nanowire. The molecular dynamics simulation technique was used to calculate the mechanical properties at constant temperature, constant pressure ensemble. The cohesive energy of the model nanowire systems was calculated by Quantum Sutton-Chen many body potential. The temperature and the pressure of the system were controlled by Nose-Hoover thermostat and Berendsen barostat, respectivly. In addition effects of the diameter of nanowire on the mechanical properties were studied. The obtained results show that, when the diameter of Rh-Pd nanowire increase, elastic constants, bulk modulus and Young modulus all increase, and when the diameter reaches about 5.5 nm, the properties began to level off and remain constant.

PROCESS MODELLING THE CURE OF BISPHENOL-A EPOXY/JEFFAMINE SYSTEM USING ICME

2021 ◽  
Author(s):  
P. P. DESHPANDE ◽  
S. SHAH, ◽  
S. U. PATIL, ◽  
M. OLAYA ◽  
G. M. ODEGARD ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Residual Stresses ◽  
Crosslink Density ◽  
Room Temperature ◽  
Thermoset Resin ◽  
Complex Process ◽  
Computational Material ◽  
Reactive Interface ◽  
Good Agreement

The prediction of thermo-mechanical properties of a thermoset resin at different stages of cure is a complex process. An Integrated Computational Material Engineering (ICME) approach is used to predict the properties of a EPON828/Jeffamine D230 system. The proposed framework integrates two length scales - nano and microscale. Molecular Dynamics (MD) is used to predict the volume shrinkage and mechanical properties of the epoxy resin as a function of the progressing crosslink density at room temperature using the Reactive Interface forcefield (IFF-R). The predicted resin properties show good agreement with the literature, proving that IFF-R can be reliably used for this purpose. Once characterized, the predicted properties are used to further predict the effects of cure shrinkage and property transformation on the bulk-level composite residual stresses. P. P. DESHPANDE

Effect of van der Waals Interaction Strength and Nanocluster Size on the Dynamical and Mechanical Properties of 1,4-cis-polybutadiene Melts

2012 ◽  
Vol 1424 ◽  
Author(s):  
Canan Atilgan ◽  
Ibrahim Inanc ◽  
Ali Rana Atilgan
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Bulk Modulus ◽  
Residence Time ◽  
Van Der Waals ◽  
Interaction Strength ◽  
Polymeric Materials ◽  
Van Der Waals Interactions ◽  
Increasing Trend ◽  
Dynamics Simulations

ABSTRACTUsing molecular dynamics simulations, we have investigated the effect of embedding nanoclusters of radius 3-7 Å on the dynamical and mechanical properties of 1,4-cispolybutadiene melts. To see the effect of polymer-nanocluster interaction strength on the bulk modulus, the van der Waals interactions (vdW) between the polymer chain and nanocluster have been varied from weak to very stong while keeping polymer-polymer and nanoclusternanocluster interactions constant. The modulus depends on the interaction strength, but not on nanocluster size. Residence time of chains on the surface of the nanocluster (τr) has an increasing trend that reaches to a plateau as the vdW strength is increased. τr also doubles from 100 ps to 200 ps as the nanocluster size is increased from 3 to 7 Å. Our findings give clues on how the properties of polymeric materials may be controlled by nanoparticles of different chemistry and size.

scholarly journals Using Molecular Dynamics Simulation to Analyze the Feasibility of Using Waste Cooking Oil as an Alternative Rejuvenator for Aged Asphalt

2021 ◽  
Vol 13 (8) ◽  
pp. 4373
Author(s):  
Lin Li ◽  
Cheng Xin ◽  
Mingyang Guan ◽  
Meng Guo
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Elastic Modulus ◽  
Shear Modulus ◽  
Bulk Modulus ◽  
Md Simulation ◽  
Waste Cooking Oil ◽  
Dynamics Simulation ◽  
Cooking Oil ◽  
Aged Asphalt

The purpose of this study was to investigate the regeneration effect of waste cooking oil (WCO) on aged asphalt with molecular dynamics (MD) simulation, comparing it with a rejuvenator. Firstly, the molecular models of virgin and aged asphalt were established by blending the four components of asphalt (saturate, aromatic, resin, and asphaltenes). Then, different dosages of the rejuvenator and WCO (6, 9, and 12%) were included in the aged asphalt model for its regeneration. After that, MD simulations were utilized for researching the mechanical and cohesive properties of the recycled asphalt, including its density, viscosity, cohesive energy density (CED), shear modulus (G), bulk modulus (K), and elastic modulus (E). The results show that the density values of the asphalt models were relatively lower than the existing experimental results in the literature, which is mostly attributed to the fact that the heteroatoms of the asphalt molecules were not considered in the simulation. On the other hand, the WCO addition decreased the viscosity, the shear modulus (G), the bulk modulus (K), and the elastic modulus (E) of the aged asphalt, improving its CED. Moreover, the nature of the aged asphalt was gradually restored with increasing rejuvenator or WCO contents. Compared with the rejuvenator, the viscosity of the aged asphalt was more effectively restored through adding WCO, while the effect of the CED and the mechanical properties recovery of the aged asphalt was relatively low. This implies that WCO could restore partial mechanical properties of aging asphalt, which proves the possibility of using WCO as an asphalt rejuvenator. Additionally, the MD simulation played an important role in understanding the molecular interactions among the four components of asphalt and the rejuvenator, which will serve as a guideline to better design a WCO rejuvenator and optimize its content.

Molecular dynamics simulations of mechanical properties of epoxy-amine: cross-linker type and conversion degree effects

2021 ◽  
Author(s):  
Yongqin Zhang ◽  
Hua Yang ◽  
Yaguang Sun ◽  
Xiangrui Zheng ◽  
Yafang Guo
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Active Sites ◽  
Phenol Formaldehyde ◽  
Md Simulations ◽  
Crosslinking Density ◽  
Molecular Structures ◽  
Conversion Degree ◽  
Epoxy Amine ◽  
Cross Linker

Abstract In this work, molecular dynamics (MD) simulations are conducted to study the thermo-mechanical properties of a family of thermosetting epoxy-amine. The crosslinked epoxy resin EPON862 with a series of cross-linkers are built and simulated under the polymer consistent force-field (PCFF). Three types of curing-agents (rigidity1,3-phenylenediamine (1,3-P), 4,4-diaminodiphenylmethane (DDM), and phenol-formaldehyde-ethylenediamine (PFE)) with different number of active sites are selected in the simulations. We focus on the effects of the cross-linkers on thermo-mechanical properties such as density, glass transition temperature (T g), elastic constants, and strength. Our simulations show a significant increase in T g, Young’s modulus and yield stress with the increase of conversion degree. The simulation results revealed that the mechanical properties of thermosetting polymers are strongly dependent on the molecular structures of cross-linker and network topological properties, such as end-to-end distance, crosslinking density and conversion degree.

scholarly journals Microstructure and Mechanical Performance of Resistance Spot Welded Martensitic Advanced High Strength Steel

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1021
Author(s):  
Yunzhao Li ◽  
Huaping Tang ◽  
Ruilin Lai
Keyword(s):  
Mechanical Properties ◽  
Failure Modes ◽  
Mechanical Performance ◽  
Strong Dependence ◽  
High Strength ◽  
Weld Nugget ◽  
Resistance Spot ◽  
Pull Out ◽  
Cross Tension ◽  
Spot Welded

Resistance spot welded 1.2 mm (t)-thick 1400 MPa martensitic steel (MS1400) samples are fabricated and their microstructure, mechanical properties are investigated thoroughly. The mechanical performance and failure modes exhibit a strong dependence on weld-nugget size. The pull-out failure mode for MS1400 steel resistance spot welds does not follow the conventional weld-nugget size recommendation criteria of 4t0.5. Significant softening was observed due to dual phase microstructure of ferrite and martensite in the inter-critical heat affected zone (HAZ) and tempered martensite (TM) structure in sub-critical HAZ. However, the upper-critical HAZ exhibits obvious higher hardness than the nugget zone (NZ). In addition, the mechanical properties show that the cross-tension strength (CTS) is about one quarter of the tension-shear strength (TSS) of MS1400 weld joints, whilst the absorbed energy of cross-tension and tension-shear are almost identical.

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