Estimation of the Elastic Properties of Polymer Plates Using a Structured Light Technique

Experimental Techniques, 2019

Engineering elastic constants and strength parameters shall be known to the designer in order to predict the structural response of composite materials. These properties shall be determined in various directions as per the designated standards. Testing of composite materials under the combined effect of in-plane shear and normal stress is of great importance. In this work, a new Arcan fixture has been designed, and then manufactured from aluminum alloy AA7075-T73. This test fixture can be used for uniaxial as well as biaxial testing of fiber reinforced polymers (FRPs) laminates in pure shear, and combined normal/shear stress states. Nevertheless, the fixture can be used for other materials where combined in-plane testing is required including metals and polymers. The special butterfly shape Arcan specimen was optimized based on the parametric study in ABAQUS environment by a Python scripting. The objective of the parametric study was to get a uniform shear stress field in the notch section of the specimen which is the cross-sectional area between the two opposite V-notch roots. The domain of the uniform shear stress-strain distribution in the notch section must be greater enough than the size of the strain gauge rosettes where these can be effectively installed for strain acquisition. The experimental setups for the realization of pure shear stress, normal stress, and combined normal/shear stress scenarios are schematically elaborated. The pure shear stress-strain response based on the Arcan test was compared with the tensile testing of ±45 0 symmetric laminate.

Science and engineering of composite materials, 1992

Materiale Plastice, 2010

In the recent years the utilization of polymeric materials increased due to their good mechanical properties and easy manufacturing. Starting from automotive industry up to food industry polymeric materials are used for obtaining components by molding or by machining. Taking into account the wide range of applications, it is important to know the mechanical behaviour of these materials in different loading conditions. Accordingly, this paper presents an experimental study to determine mechanical properties on 11 commercial polymeric materials. Tensile and shear static tests and impact tests on notched and un-notched specimens were performed. The results are presented comparatively, and two new parameters were introduced for material selection purpose.

Polymer Testing, 2002

Anisotropic polymeric matrix composite discs supported on three points were subjected to a non-destructive bending test to study their behaviour in complex flexural loading situations. The results show that the flexural behaviour of the composites depends on several factors, such as fibre orientation, laminate stacking, surface waviness and moulding temperature. The experimental data were compared with those obtained from the finite element program software Algor. Differences up to 13% were found between the experimental and simulated values of the flexural stiffness. In spite of that, it was concluded that the non-destructive test used is a useful tool to predict the behaviour of anisotropic composites and to validate the results obtained from computer FEM analysis.

Additive Manufacturing, 2018

3D printing, more formally known as Additive Manufacturing (AM), is already being adopted for rapid prototyping and soon rapid manufacturing. This review provides a brief discussion about AM and also the most employed AM technologies for polymers. The commonly-used ASTM and ISO mechanical test standards which have been used by various research groups to test the strength of the 3D-printed parts have been reported. Also, a summary of an exhaustive amount of literature regarding the mechanical properties of 3D-printed parts is included, specifically, properties under different loading types such as tensile, bending, compressive, fatigue, impact and others. Properties at low temperatures have also been discussed. Further, the effects of fillers as well as post-processing on the mechanical properties have also been discussed. Lastly, several important questions to consider in the standardization of mechanical test methods have been raised.

Prediction of the flexural strength of a laminated composite is important for engineering application yet difficult in nature. The purpose of this work is to experimentally analyze the progressive failure process of laminated composites subjected to a bending load, with application to different reinforced fibers. The analysis is based on the classical lamination theory and a bridging micromechanics model. Only the mechanical properties of constituent fiber and matrix materials under the bending load condition and the laminate geometric parameters are required. All these data can be measured independently before composite fabrication. As the internal stresses in the fiber and matrix have been explicitly determined using the bridging model, a lamina in the laminate is considered to have failed whenever any of its constituents fails, according to a stress failure criterion. Then, a stiffness discount is applied to the failed lamina, and a predicted progressive failure process results. Unlike in an in-plane load situation where the ultimate tensile strength occurs when the laminate's last ply fails, the ultimate bending strength of the laminate is attained generally before its last-ply failure. As one does not know a priori which ply failure corresponds to the ultimate failure, the use of only the stress failure criterion is no longer sufficient for the determination of the laminate ultimate strength. An additional critical deflection or curvature condition must be adopted either. The critical deflection or curvature is the laminate deflection or curvature corresponding to which the ultimate bending strength is measured. Experiments have been INTERNATIONAL JOURNAL OF MECHANICAL ENGINEERING AND TECHNOLOGY (IJMET) ISSN 0976 – 6340 (Print) ISSN 0976 – 6359 (Online) Volume 3, Issue 3, September - December (2012), pp. 504-510 © IAEME: www.iaeme.com/ijmet.asp Journal Impact Factor (2012): 3.8071 (Calculated by GISI) www.jifactor.com IJMET © I A E M E International Journal of Mechanical Engineering and Technology (IJMET), ISSN 0976 – 6340(Print), ISSN 0976 – 6359(Online) Volume 3, Issue 3, Sep- Dec (2012) © IAEME 505 carried out to obtain the bending stiffness and strength of laminated beams reinforced with six layers of bi-woven plain glass cloth and carbon fibers under three-point bending. The laminate lay-ups used are: [0], where 0 denotes that the fabric along the beam axial direction. For these laminates and based on the stress failure criterion, the measured load-deflection curves till the -ply failure agree reasonably with the available literature data. By incorporating with the critical deflection condition, the laminate ultimate bending strengths thus obtained correlate favorably with the measured results.

Low-volume production components represent a possibility to create prototypes from the same process and materials that someone use for the final product and to bring new products to market instead of waiting for final components to arrive from the machine shop. Additive FDM create geometrical products through the deposition of ABS (Acrylonitrile-Butadiene-Styrene) filaments layer by layer satisfying this necessity. Since the specialized literature offers little information on the properties of such plastic materials, in this paper the authors present some experimental procedures in order to evaluate the elastic and mechanical properties of such a plastic material. The specimens have been printed on a 3D "ULTIMAKER -2" printer.

Composite materials and 3D printing currently constitute an alternative for manufacturing automotive parts. The objective of the present research was to characterize a material composed by a photopolymer resin matrix reinforced with natural abaca and cabuya fibers and made by 3D printing, for its application in auto parts manufacturing. The directional grid of the air conditioning duct of an automotive is selected as the subject of study, and its mechanical characteristics are compared by means of experimental analysis and computational simulation. A composite volumet-ric reinforcement fiber with a fraction of 20% in the two types of fibers, was proposed for manufacturing the test specimens, and the bending test was carried out according to the ASTM 790 standard. As a result of the mechanical characterization of the manufactured materials, it was obtained that the maximum bending stress of the compounds reinforced with abaca (77.53 MPa) and cabuya (83.26 MPa) decreased with respect to the matrix material (92.77 MPa), while the modulus of elasticity to bending of the compounds reinforced with abaca (2211,33 MPa) and cabuya (1806,03 MPa) increased with respect to the matrix material (1689,64 MPa). This indicates an increase in the rigidity of the characterized materials, making possible the substitution of the matrix material.

Strojnícky časopis - Journal of Mechanical Engineering, 2019

The stress distribution in specimens designed for the tensile testing is evaluated in the article. The reinforcement consists of long fibers that copy the outer contour of the specimen. The fibers are inserted within the curvature at the edge of the specimen with the neck. The stress distribution in fibers and matrix of dogbone specimen and specimen of rectangular shape is analyzed and compared. The analysis of stress state is analyzed in FEM software ADINA. Long fibers deposited in specimen were modeled using rebar elements.

2010

The study focuses on the influence of fiber architecture (sequence and orientation) on flexural strength of glass fiber reinforced composite material. Composite materials are used increasingly in various fields such as space and aviation industries, architectural structures, shipbuilding materials, sporting goods, and interior and structural materials of automobiles due to the excellence of mechanical characteristics as well as light weight, heat resistance, and control characteristics. The main purpose of this study is to obtain the effects of fiber sequence and orientation to the flexural properties of laminated polymer composite material. Glass fiber reinforced polymer laminates are produced with each laminate consists of four layers of lamina. The matrix used is thermoset polyester with woven roving and chopped strand mat E-glass fiber as reinforcement materials. Each sample is different from another in terms of stacking sequence and orientation angles. Hand lay-up process is us...

2022

Obtaining parts made of composite materials through 3D Printing Additive manufacturing have fully proved their usefulness due to several advantages such as: the possibility to directly create complex shapes without going through the classic process of transforming the semi-finished products into finished parts through technologies that consume resources and energy and are unfriendly to the environment. The main disadvantage of the parts made by 3D Printing technologies is that they are less resistant from a mechanical point of view. This can be solved by the development of 3D printers capable of printing composite parts consisting of a plastic matrix reinforced with continuous fibers. This research focuses on studying 4 types of 3D-printed Continuous-Fiber-Reinforced Plastics (CFRP) from the point of view of their mechanical properties: Onyx -rigid nylon in which micro carbon fibers are inserted and Onyx reinforced with carbon, glass or Kevlar fiber. Standardized specimens were made for the uniaxial tensile test and the experimental program was designed evaluating: the Elastic modulus [GPa], the Maximum Tensile stress [MPa], the Tensile strain at maximum Tensile stress [mm/mm]. The principal strains were also determined, using the digital image technique made using the Aramis system from GOM. The experimental tests confirm that these new materials will be serious candidates to be used in engineering applications in various fields.

Material Design & Processing Communications

Residual stresses and strains generated in additively manufactured (AM) components have significant impact on their dimensional integrity. This work aims at characterizing the residual strains and deformations in square plates fabricated using the fused deposition modeling (FDM) process. The induced residual strains at the end of the printing process were measured through the integration of fiber Bragg grating (FBG) sensors, while the exhibited out-of-plane deformations of the plates were obtained using the digital image correlation (DIC) technique. The experimental results demonstrate significant part distortions at the plates' corner locations but without proceeding to quantitative correlation between the FBG and the DIC measurements.

It is challenging to 3-D print functional parts with known mechanical properties using variable open source 3-D printers. This study investigates the mechanical properties of 3-D printed parts using a commercial open-source 3-D printer for a wide range of materials. The samples are tested for tensile strength following ASTM D638. The results are presented and conclusions are drawn about the mechanical properties of various fused filament fabrication materials. The study demonstrates that the tensile strength of a 3-D printed specimen depends largely on the mass of the specimen, for all materials. Thus, to solve the challenge of unknown print quality a two step process is proposed, which has a reasonably high expectation that a part will have tensile strengths described in this study for a given material. First, the exterior of the print is inspected visually for sub-optimal layers. Then, to determine if there has been under-extrusion in the interior, the samples are massed. This mass is compared to what the theoretical value is using the densities provided in this study for the material and the volume of the object. This provides a means to assist low-cost open-source 3-D printers expand the range of object production to functional parts.

Materials & Design, 2003

The paper describes a series of preliminary experiments that were conducted to investigate the mechanical properties of two stereolithography resins reinforced using commercially available nonwoven fibre mats. Two commonly used photo-curable resin systems, an acrylic and an epoxy based one, were used to laser build the test specimens. Comparisons of the mechanical properties between pure-polymer specimens and their fibre-reinforced counterparts were made, by subjecting the parts to tensile tests. It was found that the fibre-reinforced specimens yielded higher measured values of elastic modulus and ultimate tensile strength.

2020

Fiber-reinforced polymer composites have large applications in different important sectors like aerospace engineering biomedical engineering, constructions because of their light-weight and high strength. Tensile and flexural properties are the two ultimate factors for measuring the strength of materials. The role of fiber content, length, and their orientations on these two properties are explored in this study. Different chemical modifications to improve the surface property of fiber/matrix and hence improve the tensile and flexural properties of polymer composites are also reviewed in this paper. Key Word: Fiber-reinforced polymer composites; Tensile property; Flexural property; Chemical Modifications; Fiber arrangement. ------------------------------------------------------------------------------------------------------------------------------------Date of Submission: 26-10-2020 Date of Acceptance: 05-11-2020 ---------------------------------------------------------------------...