An Experimental and Numerical Study of the Tensile Behavior of PA6-GF30 under Various Environmental Conditions Nicolae Stefanoaea, Olivia-Laura Petrascu, Adrian-Marius Pascu Engineering Technology and Applied Science Research, 2026 This study analyzed the tensile behavior of PA6-GF30 composite material exposed to different environments (ambient, distilled water, cooling oil, saline solution, and UV-C radiation). Experimental tests and numerical simulations were conducted using the Finite Element Method (FEM), yielding very good correlations between the experimental and simulated results. Experimentally, the PA6-GF30 specimens showed an increase in tensile strength after immersion in distilled water (+34.00%) and saline solution (+0.28%), whereas specimens exposed to cooling oil (-6.52%) and UV-C radiation (-24.89%) exhibited reduced tensile performance. Significant differences were also observed in strain and elastic modulus across the different environments.
Strain Rate Impact into the Stress and Strain Values at Break of the PA6 GF30-Reinforced Polyamides Adrian Marius Pascu, Nicolae Stefanoaea Applied Sciences Switzerland, 2025 The study of the strain rate effects on the PA6 glass fiber-reinforced polyamide, in this specific case, PA6 GF30 (30% reinforced glass fiber), is critical due to composites widely used in automotive applications where the velocity of loading can vary significantly. Some insights into material safety under high quasistatic strain rate regime are given by understanding tensile behavior with focus on strain and stress at break. For this, using injection molding, dog bone samples were subjected to tensile tests at different strain rates, using a precise displacement control and extensometer to record the engineering stress–strain. The results demonstrate that higher strain rates increased the stiffness and strength of the specimen, shifting the stress–strain behavior to higher stress at break due to the reduced time for the polymer relaxation. However, the strain at break decreases under rapid movement, indicating the fact that the specimens exhibited reduced ductility. The results indicate a pronounced strain rate sensitivity that needs to be evaluated and considered for the design and failure mechanism of the components made of PA6 GF30, highlighting the necessity of strain rate specific mechanical characterization for accurate evaluation of performance under high quasistatic strain rate load cases, leading to a more safe and reliable design.
Damage to Natural Gas Distribution Steel Pipelines caused by Rigid Bodies resulting from the Excavation of Laying Trenches Stefan-Mihai Filip, Eugen Avrigean, Adrian-Marius Pascu Engineering Technology and Applied Science Research, 2024 The present paper focuses on analyzing the occurrence of defects such as dents and local deformations by laboratory simulations of a real case of a defect detected on a natural gas distribution pipeline lain at a depth of approximately 0.6 m. The defect is caused by a river stone which due to the compression forces, damages the pipe to the point of cracking. In the laboratory, the simulation was carried out on a steel pipe insulated with extruded polyethylene which was acted upon by a mandrel made of duralumin. The purpose of the tests is to determine the maximum values at which the pipe material fractures. It was found that the fracture of the pipes when there are rigid bodies in the protective layer of sand is accelerated by the sand existing between them and the pipe and by the change in the properties of the steel the pipes are made of when they are kept in water.
A Simulation Method for the One-time Snap-fit Assembly Process of PA6 GF60-Components Nicolae Stefanoaea, Dan-Mihai Rusu, Adrian-Marius Pascu Engineering Technology and Applied Science Research, 2024 This paper's scope is to develop an intelligible Finite Element Analysis (FEA) method, utilized to determine and quantify the assembly forces required to assemble the snap-fit component, which is made of a glass fiber reinforced polyamide (type 6, 60% glass fiber, PA6 GF50), as well as to determine the snap-fit joint maximum retention forces. The proposed FEA method is to be used in Abaqus as a standard solver type, considering its operation ease and simplicity in creating the model. The setback of implementing the standard solver approach is that during the snap-fit assembly, at a certain point in the simulation, the behavior is transformed from a static movement to a dynamic one, precisely when the snap moves backward in the assembled position, at this point, due to the dynamic behavior of the simulation, the solution will continue to diverge, and the convergence is not achieved.
Analysis on the Impact of Industrial Agents on 3D-printed Polymeric Materials in Soft Robotics Dan-Mihai Rusu, Olivia-Laura Petrascu, Alexandru Barsan, Timotei Morariu, Fineas Morariu, et al. Materiale Plastice, 2024 The study investigates the effects of aggressive factors environments commonly found in industrial environments on the elastomeric material TPU 95 A, which is integrated into a multitude of soft robotics applications. Specimens made of TPU 95 A were subjected to aggressive liquid media - cooling oil, distilled water, and ultraviolet radiation (UV-C) to evaluate changes in their mechanical and elastic properties following uniaxial tensile tests. The research, carried out using additive manufacturing technology, highlights the importance of monitoring how the external factors impact elastic and mechanical characteristics of TPU 95 A material. The results obtained after the experimental tests proves to us that the aggressive media analyzed had a greater or lesser influence on the material. By uniaxial tensile tests, it was found that the liquid absorption had a very important impact on the tensile strength of the material. For example, at 1.02% absorption in distilled water, the maximum value of the ultimate strain decreased by 0.257 mm/mm, and at 3.06% absorption in cooling oil, the maximum value of the strain decreased by 0.672 mm/mm.
The Influence of Industrial Environmental Factors on Soft Robot Materials Dan Mihai Rusu, Olivia Laura Petrașcu, Adrian Marius Pascu, Silviu Dan Mândru Materials, 2023 This work aims to identify the effects that a series of environmental factors, specific to the industrial conditions, have on the materials in the structure of soft robots and, therefore, on soft robotics systems. The purpose is to understand the changes in the mechanical characteristics of silicone materials, with the aim of transferring soft robotics applications from the sphere of services in the industrial field. Distilled water, hydraulic oil, cooling oil, and UV rays are the environmental factors considered in which the specimens were immersed/exposed for 24 h according to ISO-62/2008. The analysis was carried out on two of the most widely used materials in the field, belonging to the category of silicone rubber, which were subjected to uniaxial tensile tests on the strength testing machine Titan 2 Universal. The results show that the greatest impact on the characteristics of the two materials was when exposed to UV rays, while the other media tested had relatively little impact on the mechanical and elastic properties (tensile strength, elongation at break, and tensile modulus) of these materials.
STUDY STRAIN RATE IMPACT INTO THE STRESS AND STRAIN VALUES AT BREAK OF THE PA6 GF30 REINFORCED POLIAMYDE 39th Danubia Adria Symposium on Advances in Experimental Mechanics Das 2023, 2023
Analysis on the impact of industrial agents on 3D-printed polymeric materials in soft robotics 39th Danubia Adria Symposium on Advances in Experimental Mechanics Das 2023, 2023
Comparative analysis regarding the influence of 3D-printing strategies on the compressibility of elastomeric materials 39th Danubia Adria Symposium on Advances in Experimental Mechanics Das 2023, 2023
COMPARATIVE STUDY OF POLYAMIDE 6 (PA6) AND POLYAMIDE 6 REINFORCED WITH GLASS FIBER (PA6 GF30) 38th Danubia Adria Symposium on Advances in Experimental Mechanics Das 2022, 2022
STUDY OF IMPLEMENTATION THE TENSILE DATA OF THE GLASS FIBER REINFORCED POLYAMIDE INTO THE FINITE ELEMENT ANALYSES 38th Danubia Adria Symposium on Advances in Experimental Mechanics Das 2022, 2022
Stress and strain distribution in perforated plate loaded in median plane 36th Danubia Adria Symposium on Advances in Experimental Mechanics Das 2019, 2019
Key factors towards a high quality additive manufacturing (3D printing) process with ABS material 35th Danubia Adria Symposium on Advances in Experimental Mechanics, 2018
Study regarding the geometrical deviations for 3D printed functional parts 35th Danubia Adria Symposium on Advances in Experimental Mechanics, 2018
Experimental studies on uniaxial and echibiaxial tensile tests applied to plastic materials sheets 35th Danubia Adria Symposium on Advances in Experimental Mechanics, 2018
Optical study for springback prediction, thickness reduction and forces variations on single point incremental forming 35th Danubia Adria Symposium on Advances in Experimental Mechanics, 2018
Experimental and numerical study regarding the paralel plane test for polyethylene pipe stiffness 30th Danubla Adria Symposium on Advances in Experimental Mechanics Das 2013 Proceedings, 2013
Numerical study about the strain analysis and the marginal design of dental indirect restorations Romanian Biotechnological Letters, 2012
Temperature and loading speed influence on the polyamide 6.6 Yarn-to-Yarn frictions 28th Danubia Adria Symposium on Advances in Experimental Mechanics Das 2011, 2011
Experimental studies regarding the single point incremental forming process Academic Journal of Manufacturing Engineering, 2010
Non-destructive composite testing using transient thermography method Academic Journal of Manufacturing Engineering, 2010
Experimental strain field distribution in ankle-foot orthosis (AFO) Proceedings of the 2nd Wseas International Conference on Biomedical Electronics and Biomedical Informatics Bebi 09, 2009
Numerical simulation of the incremental forming process for knee implants Computational Plasticity X Fundamentals and Applications, 2009
Fatigue mechanism and multistage fatigue modeling for wrought Mg-3Al-1Zn TMS Annual Meeting, 2009
Stress and strain field distribution in Ankle-Foot Orthosis (AFO) using FEM Annals of Daaam and Proceedings of the International Daaam Symposium, 2009
Determination of forces at the bending of perforated plates with slotted holes through experimental and FEM Annals of Daaam and Proceedings of the International Daaam Symposium, 2009
Determination of the stress and strain states and regression equations for different parameters in perforated plates with square holes placed in a parallel pattern, stressed with uniaxial traction Wseas Transactions on Computers, 2007
Constructive optimisation of the elastic element comprised in a mechanic dynamometer by finite element method 24th Danubia Adria Symposium on Developments in Experimental Mechanics Das 2007, 2007
Computational fluid dynamics for thermal analysis of a standard PC system Proceedings 2005 International Symposium on Microelectronics Imaps 2005, 2005
