DYNAMIC RESPONSE OF PHOTOPOLYMER RESINS CORES FOR NAVAL APPLICATIONS IN EXTREME ENVIRONMENTS

2021 ◽  
Author(s):  
ZACKERY NIETO ◽  
ALEJANDRA G. CASTELLANOS

Due to the melting of polar ice caps, large deposits of natural resources are becoming more readily available, leading to an increase in arctic naval exploration. Naval vessels and ship hulls must be built with lightweight structures, such as sandwich composites, to increase the ship’s fuel efficiency. However, identifying new material choices that can withstand the harsh Arctic environments is crucial for the survivability and safety of personnel and structures. This study investigates the potential of photopolymer resins through additive manufacturing as a lightweight sandwich composite core material. The thermo-mechanical properties of this resin were evaluated using: tensile, flexural, and compressive tests according to the ASTM Standards D638, D695, and D790, respectively. Tests were conducted at room temperature (23 C) and arctic temperature (-60 C). The experimental data will be used as an input for high-fidelity finite element (FE) simulations with the software ABAQUS. From the performed tests, the photopolymer exhibited isotropic behavior at both room (RT) and Arctic temperatures. Preliminary quasi-static results for “Durable Resin” at AT showed an increase of ~300% in its tensile, flexural, and compressive modulus and an increase of ~300% in its tensile and flexural strength and ~100% in its compressive strength when compared to the same resin at RT. The finite element analysis models showed good agreement with the experimental results. Zackery Nieto, The University of Texas at El Paso, 500 W. University Ave, El Paso,

Author(s):  
Y P Ravitej ◽  
V Swaroop ◽  
S Ramesh ◽  
H Adarsha ◽  
Veerachari ◽  
...  

Author(s):  
Özgün Şener ◽  
Oğuzhan Dede ◽  
Oğuz Atalay ◽  
Mert Atasoy ◽  
Altan Kayran

Transverse shear moduli of the sandwich core and flexural stiffness of all-composite sandwich constructions are determined with three-point beam bending tests, and compared with the analytical and finite element analysis solutions. Additionally, Digital Image Correlation (DIC) system is employed to validate the experimental results by monitoring the displacements. The effect of orientation of the composite core material with respect to the beam axis on the shear modulus of the core material itself, flexural stiffness of the sandwich beam, maximum loading, and the maximum stresses on the sandwich panel are also examined. Comparable results are achieved through experiments, finite element and analytical analyses.


2014 ◽  
Vol 711 ◽  
pp. 535-541
Author(s):  
Mohd Affiq Jamaluddin ◽  
Mohd Shahir Liew ◽  
Kurian V. John ◽  
Lee Hsiu Eik

This paper presents the finite element structural sensitivity analysis of a cable guyed monotower known as the Tarpon Monopod when subjected to extreme environments in Malaysian waters. A hydrodynamic loading and static platform response analysis is performed in SACS v5.3 to gauge the structural robustness in extreme Malaysian metocean conditions. A Stokes Fifth Order Wave Theory was employed to obtain wave kinematics and dynamics for load computation. The Tarpon Monopod design is reviewed generically. An actual platform located in 60m water depth within Malaysian waters is modelled for analysis. Four different guying cable scenarios are considered which are the fully guyed condition (three guy cables pinned), two guy cables condition (one wire loss), one guy cable condition (two wire loss) and free standing condition (total loss of guy wires) are presented. The environmental load sets are simulated at different headings using 45 degree steps. The results suggest that the structural caisson contributes little to the lateral stiffness of the platform. The Tarpon Monopod has little structural redundancy and its integrity is highly dependent on guy wire condition and environmental load headings.


Author(s):  
C. Yüce ◽  
F. Karpat ◽  
N. Yavuz ◽  
Ö. Kaynaklı ◽  
E. Dolaylar ◽  
...  

Profitability is the key concern for transport companies. Costs are increased due to the rising fuel prices and technological investments. As well as new legal restrictions on the emission rates have forced the sector different fuel efficient technologies. Reducing weight is one of the most important methods of improving fuel efficiency and cutting CO2 emissions. Accordingly lighter, more fuel efficient, environmentally sustainable and safety vehicles are in the priority list of European authorities. And also the future of hybrid and electric vehicles depends on the lightweighting. The seat structure was chosen as the area for study which presented the best opportunity for weight reduction by the use of new materials. A seat provides comfort and safety of an occupant’s while travelling. In the event of crash, the passenger seat is exposed many different forces. For this reason it should be designed sufficient strength and stiffness. Therefore an optimized seat design should be aesthetically pleasing, ergonomic, light and meet the safety requirements. Seats play an important role in mass of buses and coaches due to number of seats per vehicle. In this project, finite element analysis, together with topology and free-size optimization is used to design a lightweight passenger seat for new generation commercial vehicles. The seat CAD models were created with CATIA V5 and then imported into HyperMesh for finite element model creation and analysis. Results from the nonlinear analysis provide an accurate prediction of the material yielding and load path distribution on the seat structural frame components. In the end, the verification tests which were determined by ECE are applied the new seat and results were compared with the FEA results. In this study, the lightweight passenger seat prototypes have developed. High strength steel and fiber-reinforced plastic parts are used. An overall 20% weight reduction is achieved including the structural frame, cushion, armrest, and pillar. And also the new passenger seat provides ECE safety norms.


2017 ◽  
Vol 1143 ◽  
pp. 139-144 ◽  
Author(s):  
Florentina Rotaru ◽  
Ionel Chirica ◽  
Elena Felicia Beznea

In this paper the influence cell honeycomb geometry on the mechanical behaviour of a composite sandwich plate is analyzed. Three cell geometries (circular, hexagonal and square) are static analysed so that to select the best type of honeycomb that will be used in the manufacturing the sandwich plate core. The main aim is to develop approach models of equivalent orthotropic materials to replace the real model of honeycomb core with their properties so that to quickly calculate the sandwich plate made out of composite when is used a finite element analysis code. Geometry and material properties of the honeycomb are delivered by the material provider. Comparative analysis, by using Finite element analysis is performed for all geometries, in the same boundary conditions. Since in the impact loading of the composite sandwich plate the core is mainly loaded to compression, comparative study of the three cell geometries honeycomb was performed for this type of compressive loading. Since the cell is the basic element of the honeycomb core, the calculus is performed for one unit volume of sandwich, concerning also the part of skins.


2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Ki-Sun Lee ◽  
Joo-Hee Shin ◽  
Jong-Eun Kim ◽  
Jee-Hwan Kim ◽  
Won-Chang Lee ◽  
...  

The aim of this study was to evaluate the biomechanical behavior and long-term safety of high performance polymer PEKK as an intraradicular dental post-core material through comparative finite element analysis (FEA) with other conventional post-core materials. A 3D FEA model of a maxillary central incisor was constructed. A cyclic loading force of 50 N was applied at an angle of 45° to the longitudinal axis of the tooth at the palatal surface of the crown. For comparison with traditionally used post-core materials, three materials (gold, fiberglass, and PEKK) were simulated to determine their post-core properties. PEKK, with a lower elastic modulus than root dentin, showed comparably high failure resistance and a more favorable stress distribution than conventional post-core material. However, the PEKK post-core system showed a higher probability of debonding and crown failure under long-term cyclic loading than the metal or fiberglass post-core systems.


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