97,639 research outputs found
Joshua Davis: Author of Spare Parts
No full textCitation: K-State First (2016). Joshua Davis: Author of Spare Parts [Flier]. Manhattan, Kansas: K-State First.Flyer advertising Joshua Davis's author talk at Kansas State University
Steven Johnson Author Talk Poster
No full textK-State Book NetworkA poster advertising an author talk by Steven Johnson at Kansas State University on September 3, 2014. Steven Johnson's book "The Ghost Map" was the 2014-2015 common book
Influence of Milled Glass Fiber Fillers on Mode I & Mode II Interlaminar Fracture Toughness of Epoxy Resin for Fabrication of Glass/Epoxy Composites
No full textThe present work is focused on improving mode I and mode II delamination resistance of glass/epoxy composite laminates (50 wt.% of glass fibers) with milled glass fibers, added in various amounts (2.5, 5, 7.5 and 10% of the epoxy weight). Including fillers in the interlayer enhances the delamination resistance by providing a bridging effect, therefore demanding additional energy to initiate the crack in the interlaminar domain, which results in turn in enhanced fracture toughness. The maximal increase of mode I and mode II fracture toughness and of flexural strength was obtained by the addition of 5% milled glass fiber. The mechanism observed suggests that crack propagation is stabilized even leading to its arrest/deflection, as a considerable amount of milled glass fiber filler was oriented transverse to the crack path. In contrast, at higher filler loading, tendency towards stress concentration grows due to local agglomeration and improper dispersion of excess fillers in inter/intralaminar resin channel, causing poor adhesion to the matrix, which leads to reduction in fracture toughness, strength and strain to failure. Fractured surfaces analyzed using scanning electron microscopy (SEM) revealed a number of mechanisms, such as crack deflection, individual debonding and filler/matrix interlocking, all contributing in various ways to improve fracture toughness
Quasi-static indentation behavior of GFRP with milled glass fiber filler monitored by acoustic emission
No full textThis paper aims at investigating the influence of the addition of milled glass fibers upon quasi-static indentation (QSI) properties of glass/epoxy composite laminates. The QSI behavior was experimentally studied by evaluating indentation force, residual dent depth, energy absorbed and size of the damaged area for different indentation depths. Following the QSI tests, the filler-loaded glass/epoxy samples were subjected to three-point bending tests in order to measure residual flexural strength, and the results were compared with the baseline glass/epoxy samples. Both tests were performed with online acoustic emission monitoring in order to observe damage progression and characterize different fracture mechanisms associated with loading. The results show that the filler-loaded laminates exhibit a substantial improvement in the peak force and contact stiffness, with a reduced permanent damage both in terms of depth and of area, in comparison with the baseline ones. It is found that the filler presence offers greater stiffness and higher energy dissipation through toughening mechanisms such as filler debonding/pullout and filler bridging/interlocking
Damage characterization of stiffened glass-epoxy laminates under tensile loading with acoustic emission monitoring
No full textThe design of composite components in the aerospace industry often includes structural discontinuities, such as cutouts, for functional requirements like ventilation, tunnel passage, maintenance and repair. The presence of cutout holes leads to complicated stress concentrations with a substantial reduction in structural stability and strength of the resulting composites. It is known that reinforcing with additional material at the cutout zones can extend the damage tolerance of a structure, therefore maintaining structural integrity and load carrying capacity. This study focuses on the experimental investigation of the tensile behavior and failure characteristics of stiffened glass/epoxy composite laminates, with cutouts, under acoustic emission monitoring. The progressive failure mechanisms of laminates with cutouts and the potential benefits of additionally dropped reinforcements are evaluated under tensile loading. The additional reinforcements were provided in either a step-like or as a simultaneous drop-off sequence between adjacent continuous plies. Results showed that adding ply drop reinforcements at the location of the cutout hole improves the stiffness, strength, and also prolongs the life of the composite laminates. It is also observed that step-like ply drop arrangements performed more effectively than simultaneously dropped configurations. The location and extent of damage identified by microscopic images correlated well with the acoustic emission results
Defensing Confidentiality During Complete Packet Inspection On A Middlebox
No full textIn Internet to encrypt traffic, HTTPS provides secure and private data communication between clients and servers. Network operators often deploy middleboxes to perform deep packet inspection DPI to detect attacks using techniques ranging from simple keyword matching to more advanced machine learning and data mining analysis. But this approach cannot protect users' private information from a service provider who deploys middleboxes. SPABox, a middlebox based system that supports both keyword based and data analysis based DPI functions over encrypted traffic. SPABox preserves privacy by using a novel protocol with a limited connection setup overhead. In this paper to further improve the performance, we are working on the network performance requirements. K. Geetharani | K. Kowsalya | A. M. SenthilKumar | M. S. Vijaykumar | M. Saravanakumar "Defensing Confidentiality During Complete Packet Inspection On A Middlebox" Published in International Journal of Trend in Scientific Research and Development (ijtsrd), ISSN: 2456-6470, Volume-2 | Issue-3 , April 2018, URL: https://www.ijtsrd.com/papers/ijtsrd10725.pd
Compression after impact strength of repaired GFRP composite laminates under repeated impact loading
No full textDuring their service life, composite materials are prone to damage, which compromises their structural
performance significantly. In this study, glass/epoxy composite specimens fabricated using hand layup
method and further cured in a compression molding machine were cut from the laminates and subjected
to low velocity impact damage in order to investigate the effects of repair. The impacted laminates were
repaired by removing the damage area with a circular cutout and filled with a chopped short Kevlar/
epoxy: the efficiency of the repair procedure and toughness of the repaired laminates were examined
by repeated impacts on the repaired site. The residual strength of the post impacted repaired laminates
is investigated by the conduction of compression after impact (CAI) loading with acoustic emission
monitoring (AE) technique. The structural performance of both repaired and unrepaired laminates are
compared and discussed
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Residual strength estimation and damage characterization by acoustic emission of drilled thermally conditioned fiberglass laminates
No full textStructural components of composite materials in aerospace industries are assembled using fasteners, installed by performing cutting processes, such as drilling, on the material. In composites, this is considered particularly critical, because delamination due to mechanical stresses and fiber/resin pullout may be facilitated during cutting, so that the structural integrity of composite laminates may be affected. Acoustic emission (AE) technique is employed to monitor the failure modes and damage mechanism of drilled composite materials, while in an attempt to improve the strength of the composites, thermal conditioning has been applied. This paper investigates the residual performance of drilled unidirectional glass fiber reinforced plastic (GFRP) laminates subjected to various thermal conditioning methods. Thermally treated laminates underwent three-point flexural tests under AE monitoring to compare their residual strength with the untreated ones. The results clearly show that the thermal conditioning could be used as an effective method for minimizing delamination in GFRPs
Finite-Time Passivity-Based Stability Criteria for Delayed Discrete-Time Neural Networks via New Weighted Summation Inequalities
No full textIn this paper, we study the problem of finite-time stability and passivity criteria for discrete-time neural networks (DNNs) with variable delays. The main objective is how to effectively evaluate the finite-time passivity conditions for NNs. To achieve this, some new weighted summation inequalities are proposed for application to a finite-sum term appearing in the forward difference of a novel Lyapunov-Krasovskii functional, which helps to ensure that the considered delayed DNN is passive. The derived passivity criteria are presented in terms of linear matrix inequalities. A numerical example is given to illustrate the effectiveness of the proposed results
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