scholarly journals Magnetorheological composite materials (MRCMs) for instant and adaptable structural control

2020 ◽  
Author(s):  
Travis Thornell ◽  
Charles Weiss ◽  
Sarah Williams ◽  
Jennifer Jefcoat ◽  
Zackery McClelland ◽  
...  
Keyword(s):  
Composite Materials ◽  
Structural Control ◽  
Soft Materials ◽  
Material System ◽  
Butadiene Rubber ◽  
Parallel Plates ◽  
Kaolinite Clay ◽  
Responsive Materials ◽  
Structural Applications ◽  
Cementitious System

Magnetic responsive materials can be used in a variety of applications. For structural applications, the ability to create tunable moduli from relatively soft materials with applied electromagnetic stimuli can be advantageous for light-weight protection. This study investigated magnetorheological composite materials involving carbonyl iron particles (CIP) embedded into two different systems. The first material system was a model cementitious system of CIP and kaolinite clay dispersed in mineral oil. The magnetorheological behaviors were investigated by using parallel plates with an attached magnetic accessory to evaluate deformations up to 1 T. The yield stress of these slurries was measured by using rotational and oscillatory experiments and was found to be controllable based on CIP loading and magnetic field strength with yield stresses ranging from 10 to 104 Pa. The second material system utilized a polystyrene-butadiene rubber solvent-cast films with CIP embedded. The flexible matrix can stiffen and become rigid when an external field is applied. For CIP loadings of 8% and 17% vol %, the storage modulus response for each loading stiffened by 22% and 74%, respectively.

Information in United States Patents on works related to ‘Natural Fibers’: 2000-2018

2019 ◽  
Vol 12 (1) ◽  
pp. 4-76 ◽  
Author(s):  
Krittirash Yorseng ◽  
Mavinkere R. Sanjay ◽  
Jiratti Tengsuthiwat ◽  
Harikrishnan Pulikkalparambil ◽  
Jyotishkumar Parameswaranpillai ◽  
...  
Keyword(s):  
United States ◽  
Composite Materials ◽  
Natural Fiber ◽  
Comprehensive Evaluation ◽  
Natural Fibers ◽  
Fiber Reinforced Composites ◽  
Reinforced Composites ◽  
Fiber Reinforced ◽  
Macro Scale ◽  
Structural Applications

Background: This era has seen outstanding achievements in materials science through the advances in natural fiber-based composites. The new environmentally friendly and sustainability concerns have imposed the chemists, biologists, researchers, engineers, and scientists to discover the engineering and structural applications of natural fiber reinforced composites. Objective: To present a comprehensive evaluation of information from 2000 to 2018 in United States patents in the field of natural fibers and their composite materials. Methods: The patent data have been taken from the external links of US patents such as IFI CLAIMS Patent Services, USPTO, USPTO Assignment, Espacenet, Global Dossier, and Discuss. Results: The present world scenario demands the usage of natural fibers from agricultural and forest byproducts as a reinforcement material for fiber reinforced composites. Natural fibers can be easily extracted from plants and animals. Recently natural fiber in nanoscale is preferred over micro and macro scale fibers due to its superior thermo-mechanical properties. However, the choice of macro, micro, and nanofibers depends on their applications. Conclusion: This document presents a comprehensive evaluation of information from 2000 to 2018 in United States patents in the field of natural fibers and their composite materials.

Predictions of the Mechanical Performance of Leaf Fiber Thermoplastic Composites by FEA

2021 ◽  
Author(s):  
Faris M. AL-Oqla
Keyword(s):  
Composite Materials ◽  
Cantilever Beam ◽  
Mechanical Performance ◽  
Natural Fiber ◽  
Fiber Composite ◽  
Fiber Composites ◽  
Fiber Types ◽  
Natural Fiber Composites ◽  
Pull Out ◽  
Structural Applications

The available potential plant waste could be worthy material to strengthen polymers to make sustainable products and structural components. Therefore, modeling the natural fiber polymeric-based composites is currently required to reveal the mechanical performance of such polymeric green composites for various green products. This work numerically investigates the effect of various fiber types, fiber loading, and reinforcement conditions with different polymer matrices towards predicting the mechanical performance of such natural fiber composites. Cantilever beam and compression schemes were considered as two different mechanical loading conditions for structural applications of such composite materials. Finite element analysis was conducted to modeling the natural fiber composite materials. The interaction between the fibers and the matrices was considered as an interfacial friction force and was determined from experimental work by the pull out technique for each polymer and fiber type. Both polypropylene and polyethylene were considered as composite matrices. Olive and lemon leaf fibers were considered as reinforcements. Results have revealed that the deflection resistance of the natural fiber composites in cantilever beam was enhanced for several reinforcement conditions. The fiber reinforcement was capable of enhancing the mechanical performance of the polymers and was the best in case of 20 wt.% polypropylene/lemon composites due to better stress transfer within the composite. However, the 40 wt.% case was the worst in enhancing the mechanical performance in both cantilever beam and compression cases. The 30 wt.% of polyethylene/olive fiber was the best in reducing the deflection of the cantilever beam case. The prediction of mechanical performance of natural fiber composites via proper numerical analysis would enhance the process of selecting the appropriate polymer and fiber types. It can contribute finding the proper reinforcement conditions to enhance the mechanical performance of the natural fiber composites to expand their reliable implementations in more industrial applications.

Novel Approach for the Lifetime Prediction of Composite Materials under Static Loads

2019 ◽  
Vol 809 ◽  
pp. 620-624
Author(s):  
Stefan Gloggnitzer ◽  
Gerald Pilz ◽  
Christian Schneider ◽  
Gerald Pinter
Keyword(s):  
Composite Materials ◽  
Creep Rupture ◽  
Stress Rate ◽  
Testing Time ◽  
Creep Tests ◽  
Static Loads ◽  
Rate Dependent ◽  
R Ratio ◽  
Structural Applications ◽  
Load Rate

Composite materials in structural applications that are subjected to static loads for several decades tend to change material performance over their lifetime. Classical creep tests with constant static loading are quite simple tests with low demands on the test equipment. Unfortunately, these tests require uneconomically long test times, which is why a shortening of the test times with various accelerated approaches is being researched. Within this work two approaches for reduction of the testing time were investigated. On the one hand a fatigue test with the variation of R-ratio and following extrapolation to an R-ratio of 1 was done. On the other hand a Stress Rate Accelerated Creep Rupture Test (SRCR) was developed, where a defined initial stress σi is applied at the beginning of the loading process, followed by an increase load with a constant rate instead of the static stress segment of the classic creep rupture tests. Changing the load rate in several individual tests leads to stress rate-dependent fracture strengths with associated fracture times, which allows extrapolation to a fracture time at a load rate of zero. In particular, the approach of the SRCR offers great potential for greatly reducing test times with an acceptable prediction quality.

An Orthotropic Integrated Flow-Stress Model for Process Simulation of Composite Materials—Part I: Two-Phase Systems

2019 ◽  
Vol 141 (3) ◽  
Author(s):  
Sina Amini Niaki ◽  
Alireza Forghani ◽  
Reza Vaziri ◽  
Anoush Poursartip
Keyword(s):  
Composite Materials ◽  
Flow Stress ◽  
Interactive Effect ◽  
Fluid Phase ◽  
Solid Material ◽  
Material System ◽  
Two Phase ◽  
Stress Development ◽  
Thermoset Resin ◽  
Three Phase

An integrated flow-stress (IFS) model provides a seamless and mechanistic connection between the two distinct regimes during the manufacturing process of composite materials, namely, fluid flow in the pregelation stage of the thermoset resin and stress development in the composite when it acts as a solid material. In this two-part paper, the two- and three-phase isotropic IFS models previously developed by the authors are extended to the general case of composite materials with orthotropic constituents. Part I presents the two-phase, fluid-solid, orthotropic model formulation for the case where the fluid phase solidifies during the course of curing. Part II extends the orthotropic formulation to a three-phase model that includes a gas phase as the third constituent of the composite material system. A broader definition of material properties in poroelasticity formulation is adopted in the development of the general orthotropic formulation. The model is implemented in a two-dimensional (2D) plane strain u-v-P finite element (FE) code and its capability in predicting the flow-compaction behavior and stress development is demonstrated through application to a case study involving an L-shaped unidirectional laminate undergoing curing on a conforming convex tool. Comparison of the results with those obtained from sole modeling of the stress development reveals the importance of capturing the simultaneous and interactive effect of the mechanisms involved during the entire process cycle using an IFS modeling approach presented in this paper.

A new method for ultrasonic detection of peel ply at the bondline of out-of-autoclave composite assemblies

2018 ◽  
Vol 53 (2) ◽  
pp. 245-259
Author(s):  
Gary S LeMay ◽  
Davood Askari
Keyword(s):  
Signal To Noise Ratio ◽  
Three Dimensional ◽  
Ultrasonic Pulse ◽  
Woven Fabric ◽  
Material System ◽  
Signal To Noise ◽  
Structural Applications ◽  
Peel Ply ◽  
Noise Ratio ◽  
Out Of Autoclave

Out-of-autoclave materials have long been an established material system for secondary structural applications; however, recent advancements in material properties allow for more advanced structural applications. Even though certain out-of-autoclave properties have achieved parity with autoclaved cured materials, out-of-autoclave materials are cured at reduced temperatures and pressures resulting in less compaction and homogeneity. The consequence is extraneous ultrasonic signals, due to internal reflections and refractions that cause attenuation, potentially masking defects leading to unidentifiable indications. Advanced algorithms were developed to improve the signal to noise ratio between constituents of similar acoustic impedance in bonded out-of-autoclave carbon fiber reinforced polymer assemblies. Conventional ultrasonic nondestructive testing techniques and analysis software cannot consistently achieve signal to noise ratios that meet quantifiable rejection thresholds of accurately sized peel ply inserts at the bonded interface of composite assemblies. Ultrasonic pulse echo with full waveform capture was used to inspect a reference standard with peel ply inserts placed between the adhesive and three-dimensional-woven fabric preform. The ultrasonic signal was produced by a 64 element array transducer with a central frequency of 2.8 MHz. Waveform post-acquisition analysis with post processing software was used to analyze and enhance the signal response between the peel ply and the bondline resulting in the final algorithm. To verify the results, the signal to noise ratio of each insert was calculated for both the raw and processed data. As the measure of detectability, the method relies on principles of statistical measurement to provide an industry standard signal to noise response of 3:1.

scholarly journals Evaluation of surface roughness in drilling particle-reinforced composites

2020 ◽  
Vol 29 ◽  
pp. 2633366X2093771
Author(s):  
Ferit Ficici
Keyword(s):  
Surface Roughness ◽  
Composite Materials ◽  
Feed Rate ◽  
Metal Removal ◽  
Cutting Speed ◽  
Weight Fraction ◽  
Matrix Alloy ◽  
Reinforced Composites ◽  
Structural Applications ◽  
Drilling Operations

Aluminum matrix composite materials being used in different sectors including automobile, aerospace, defense, and medical and are currently displacing unreinforced materials with their superior mechanical properties. The metal removal process of drilling is widely used in many structural applications. This study experimentally investigates the drilling characteristics of silicon carbide (SiCp)-reinforced Al 7075 composites produced by stir casting method. Also, two different drill materials with high-speed steel (HSS) and titanium nitride (TiN)-coated HSS carry out in drilling operation. The effect of operational parameters such as cutting speed and feed rate and materials parameters such as weight fraction of reinforcement and cutting tools on the surface roughness of drilled holes were evaluated in the drilling operations. The results of the drilling test indicate that the feed rate and cutting speed have a very strong effect on the surface roughness of matrix alloy and composite materials. The surface roughness ( Ra) values increased with increasing the feed rate and decreased with increasing the cutting speed. Under 0.10 mm/rev and 20 m/min drilling conditions and using HSS drill, surface roughness values for matrix, 5% SiC-, 10% SiC-, and 15% SiC-reinforced composites, were obtained 2.57, 2.59, 2.61, and 2.64 µm, respectively; besides, using TiN-coated HSS drill, surface roughness values were obtained 1.60, 1.63, 1.64, and 1.66 µm, respectively. An increase in the weight fraction of the abrasive SiC particle resulted in a very crucial deterioration quality of the drilled hole. TiN-coated HSS drills better performance exhibits than uncoated HSS drills for all the drilling operations about surface roughness properties. Short chip formations observed both the matrix alloy and the composite materials for two different drills in the drilling operations.

Tailoring Composite Materials Through Optimal Selection of Their Constituents

1992 ◽  
Vol 114 (3) ◽  
pp. 451-458 ◽  
Author(s):  
H. M. Karandikar ◽  
F. Mistree
Keyword(s):  
Composite Material ◽  
Composite Materials ◽  
Multiobjective Optimization ◽  
Material Selection ◽  
The Other ◽  
Economic Factors ◽  
Optimal Selection ◽  
Structural Applications ◽  
Design Requirements ◽  
Selection Of

The use of composite materials has provided designers with increased opportunities for tailoring structures and materials to meet load requirements and changing and demanding environments. This has led to their increased use in structural applications. As with traditional materials the selection of an appropriate material for a design is important. In case of design using composite materials the selection of a material consists of selecting a fiber-resin combination which meets all design requirements. This involves choosing the fiber, the resin, and the proportion of these two constituents in the composite material. The phrase “material selection” refers to the problem of laminate selection. This corresponds to the task of choosing a fiber and resin combination based on technical and economic factors. Materials tailoring, on the other hand, involves manipulating the composition of the composite material to achieve desired properties and it is the selection of a fiber and resin simultaneously but separately. In this paper we present, through an example, a multiobjective optimization-based method for assisting a designer in tailoring composite materials for specific technical and economic objectives.

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