Dynamic Buckling Response of Long Plates for the Prediction of Local Plate Buckling of Corrugated Core Sandwich Columns

2015 ◽  
Vol 82 (11) ◽  
Author(s):  
Jae-Yong Lim ◽  
Hilary Bart-Smith
Keyword(s):  
Model Development ◽  
Local Buckling ◽  
Longitudinal Direction ◽  
Plate Buckling ◽  
Proposed Model ◽  
Constant Rate ◽  
Out Of Plane ◽  
Alternative Methodology ◽  
Buckling Failure ◽  
Plane Displacement

An analytical model predicting the dynamic local buckling failure of plates with a large dimension in the longitudinal direction compressed at a constant rate was proposed. The model began with the hypothesis that the proposed analytical approach could be an alternative methodology to approximate the dynamic local plate buckling response of constituent plates of corrugated core sandwich columns. Prior to the model development, four preliminary finite-element (FE) simulations were conducted to observe the typical dynamic response of the sandwich columns having thin core web plates or thin face sheets. From the simulations, several wrinkles with a regular pattern were generated, and then one of the wrinkles grew excessively to a failure. Accordingly, the proposed model considered an imaginary patch plate on a long plate simulating a face sheet or a core web plate. The size of the patch plate was predefined so as to encompass the major growing wrinkle, and the out-of-plane displacement was calculated till load drop. The verification of the proposed model was followed by comparison with the FE calculations. The model was satisfactory in predicting maximum forces and times-to-failure, but some discrepancies were found when postcritical behavior and plasticity were involved. The sources of the discrepancies were discussed.

scholarly journals Locally Corroded Stiffener Effect on Shear Buckling Behaviors of Web Panel in the Plate Girder

2015 ◽  
Vol 2015 ◽  
pp. 1-19 ◽  
Author(s):  
Jungwon Huh ◽  
In-Tae Kim ◽  
Jin-Hee Ahn
Keyword(s):  
Corrosion Damage ◽  
Element Analysis ◽  
Buckling Strength ◽  
Lower Shear ◽  
Out Of Plane ◽  
Shear Buckling ◽  
Buckling Failure ◽  
Plane Displacement ◽  
The Web ◽  
Plate Girder

The shear buckling failure and strength of a web panel stiffened by stiffeners with corrosion damage were examined according to the degree of corrosion of the stiffeners, using the finite element analysis method. For this purpose, a plate girder with a four-panel web girder stiffened by vertical and longitudinal stiffeners was selected, and its deformable behaviors and the principal stress distribution of the web panel at the shear buckling strength of the web were compared after their post-shear buckling behaviors, as well as their out-of-plane displacement, to evaluate the effect of the stiffener in the web panel on the shear buckling failure. Their critical shear buckling load and shear buckling strength were also examined. The FE analyses showed that their typical shear buckling failures were affected by the structural relationship between the web panel and each stiffener in the plate girder, to resist shear buckling of the web panel. Their critical shear buckling loads decreased from 82% to 59%, and their shear buckling strength decreased from 88% to 76%, due to the effect of corrosion of the stiffeners on their shear buckling behavior. Thus, especially in cases with over 40% corrosion damage of the vertical stiffener, they can have lower shear buckling strength than their design level.

Self-Sensing Solid Materials via Delamination Buckling

2017 ◽  
Author(s):  
Suihan Liu ◽  
Rigoberto Burgueño
Keyword(s):  
Biaxial Loading ◽  
Local Buckling ◽  
Measuring Method ◽  
Solid Materials ◽  
Material Body ◽  
Global Strain ◽  
Out Of Plane ◽  
Delamination Buckling ◽  
Plane Displacement ◽  
Main Material

Strain in solid materials under external loads cannot be visualized until they reach a high value or failure occurs; and the common measuring method of using strain sensors is effective but limited to wiring or power supply. In this study, we introduce a new concept of self-sensing solid materials by designing thin surface circular delamination regions on a material body to sense and predict the elastic global strain through controlled elastic local buckling. Delamination buckling is an undesirable failure occurrence in laminated composites under compression. However, it can translate imperceptible small global strains on the main material body to a visible large deformation in the surface of the delaminated region due to buckling. We analytically studied the buckling and post-buckling response of a clamped circular thin plate with unilateral constraint using an energy method to obtain the critical buckling loads, the buckling configurations, and the center out-of-plane displacement under uniaxial and biaxial loading conditions. The results show that for a given buckling configuration in the local region, the global strain condition of the main material body can be predicted. The study thus explores and proves a feasible way to design self-sensing materials through controlled delamination buckling.

BUCKLING OF COMPOSITE PLATES WITH ARBITRARY BOUNDARY CONDITIONS BY A SEMI-ANALYTICAL APPROACH

2012 ◽  
Vol 12 (05) ◽  
pp. 1250033 ◽  
Author(s):  
EUGENIO RUOCCO ◽  
VINCENZO MINUTOLO
Keyword(s):  
Analytical Approach ◽  
Composite Plates ◽  
Analytical Form ◽  
Biaxial Compression ◽  
Rectangular Plates ◽  
Arbitrary Boundary ◽  
Buckling Loads ◽  
Plate Buckling ◽  
Out Of Plane ◽  
Plane Displacement

A semi-analytical approach for the buckling analysis of symmetrically laminated rectangular plates under arbitrary constrains is presented. In the proposed method, the out-of-plane displacement field is assumed to be of a multiplicative form containing two vectors of functions, one being prescribed and the other to be determined, depend on separate variables. As a consequence, one may solve the equilibrium equation analytically, and obtain exact buckling loads for the biaxial compression and different boundary constrains. Several cases of plate buckling under different load combinations are studied, in order to demonstrate the applicability of the proposed approach. The results obtained are compared with the existing ones, where available in analytical form, and approximate results obtained by other numerical methods.

scholarly journals Experiment and Numerical Simulation for the Compressive Buckling Behavior of Double-Sided Laser-Welded Al–Li Alloy Aircraft Fuselage Panel

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3599
Author(s):  
Yunlong Zhang ◽  
Wang Tao ◽  
Yanbin Chen ◽  
Zhenkun Lei ◽  
Ruixiang Bai ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Axial Compression ◽  
Failure Load ◽  
Local Buckling ◽  
Fringe Projection ◽  
Buckling Behavior ◽  
Welded Structure ◽  
Out Of Plane ◽  
Plane Displacement ◽  
Fringe Projection Profilometry

The aim of this work was to study the buckling behavior and failure mode of the double-sided laser-welded Al–Li alloy panel structure under the effect of axial compression via experimental and numerical simulation methods. In the test, multi-frequency fringe projection profilometry was used to monitor the out-of-plane displacement of the laser-welded panel structure during the axial compression load. In addition, the in-plane deformation was precisely monitored via strain gauge and strain rosette. The basic principles of fringe projection profilometry were introduced, and how to use fringe projection profilometry to obtain out-of-plane displacement was also presented. Numerical simulations were performed using the finite element method (FEM) to predict the failure load and buckling modes of the laser-welded panel structure under axial compression, and the obtained results were compared with those of the experiment. It was found that the fringe projection profilometry method for monitoring the buckling deformation of the laser-welded structure was verified to be effective in terms of a measurement accuracy of sub-millimeter level. The structural failure was caused by local buckling of the skin. The observed failure modes such as local buckling of the skin, bending deformation of the stringers, continuous fracture of several welds, and failure of local strength and stiffness were attributed to the deformed laser-welded panel structure under the axial compression. The predicted failure load in the numerical simulation was slightly smaller than that of the experimental test, and the error of the simulation result relative to the test result was −2.7%. The difference between them might be due to the fact that the boundary and loading conditions used in the FEM model could not be completely consistent with those used in the actual experiment.

scholarly journals Sensor Integrated Load-Bearing Structures: Measuring Axis Extension with DIC-Based Transducers

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4104
Author(s):  
Nassr Al-Baradoni ◽  
Peter Groche
Keyword(s):  
Cost Effective ◽  
Image Correlation ◽  
Maximum Deviation ◽  
Single Image ◽  
Eccentric Load ◽  
Load Bearing ◽  
Out Of Plane ◽  
Axis Extension ◽  
Plane Displacement ◽  
Imaging Sensor

In this paper we present a novel, cost-effective camera-based multi-axis force/torque sensor concept for integration into metallic load-bearing structures. A two-part pattern consisting of a directly incident and mirrored light beam is projected onto the imaging sensor surface. This allows the capturing of 3D displacements, occurring due to structure deformation under load in a single image. The displacement of defined features in size and position can be accurately analyzed and determined through digital image correlation (DIC). Validation on a prototype shows good accuracy of the measurement and a unique identification of all in- and out-of-plane displacement components under multiaxial load. Measurements show a maximum deviation related to the maximum measured values between 2.5% and 4.8% for uniaxial loads ( and between 2.5% and 10.43% for combined bending, torsion and axial load. In the course of the investigations, the measurement inaccuracy was partly attributed to the joint used between the sensor parts and the structure as well as to eccentric load.

scholarly journals Multi-Layer Blockchain-Based Security Architecture for Internet of Things

Sensors ◽  
2021 ◽  
Vol 21 (3) ◽  
pp. 772 ◽  
Author(s):  
Houshyar Honar Pajooh ◽  
Mohammad Rashid ◽  
Fakhrul Alam ◽  
Serge Demidenko
Keyword(s):  
Internet Of Things ◽  
Clustering Algorithm ◽  
Model Development ◽  
Base Stations ◽  
Smart Devices ◽  
Security Model ◽  
Cluster Heads ◽  
Authentication Mechanism ◽  
Proposed Model ◽  
Authentication And Authorization

The proliferation of smart devices in the Internet of Things (IoT) networks creates significant security challenges for the communications between such devices. Blockchain is a decentralized and distributed technology that can potentially tackle the security problems within the 5G-enabled IoT networks. This paper proposes a Multi layer Blockchain Security model to protect IoT networks while simplifying the implementation. The concept of clustering is utilized in order to facilitate the multi-layer architecture. The K-unknown clusters are defined within the IoT network by applying techniques that utillize a hybrid Evolutionary Computation Algorithm while using Simulated Annealing and Genetic Algorithms. The chosen cluster heads are responsible for local authentication and authorization. Local private blockchain implementation facilitates communications between the cluster heads and relevant base stations. Such a blockchain enhances credibility assurance and security while also providing a network authentication mechanism. The open-source Hyperledger Fabric Blockchain platform is deployed for the proposed model development. Base stations adopt a global blockchain approach to communicate with each other securely. The simulation results demonstrate that the proposed clustering algorithm performs well when compared to the earlier reported approaches. The proposed lightweight blockchain model is also shown to be better suited to balance network latency and throughput as compared to a traditional global blockchain.

122 A Mechanistic Model of Growth and Amino Acid Deposition in the Pregnant Sow: Model Development, Evaluation, and Application

2021 ◽  
Vol 99 (Supplement_1) ◽  
pp. 55-56
Author(s):  
Christian D Ramirez-Camba ◽  
Crystal L Levesque
Keyword(s):  
Weight Gain ◽  
Amino Acid ◽  
Mechanistic Model ◽  
Model Development ◽  
Allantoic Fluid ◽  
Late Gestation ◽  
Maternal Body ◽  
Proposed Model ◽  
Development Evaluation ◽  
Model Weight

Abstract A mechanistic model was developed with the objective to characterize weight gain and essential amino acid (EAA) deposition in the different tissue pools that make up the pregnant sow: placenta, allantoic fluid, amniotic fluid, fetus, uterus, mammary gland, and maternal body were considered. The data used in this modelling approach were obtained from published scientific articles reporting weights, crude protein (CP), and EAA composition in the previously mentioned tissues; studies reporting not less than 5 datapoints across gestation were considered. A total of 12 scientific articles published between 1977 and 2020 were selected for the development of the model and the model was validated using 11 separate scientific papers. The model consists of three connected sub-models: protein deposition (Pd) model, weight gain model, and EAA deposition model. Weight gain, Pd, and EAA deposition curves were developed with nonparametric statistics using splines regression. The validation of the model showed a strong agreement between observed and predicted growth (r2 = 0.92, root mean square error = 3%). The proposed model also offered descriptive insights into the weight gain and Pd during gestation. The model suggests that the definition of time-dependent Pd is more accurately described as an increase in fluid deposition during mid-gestation coinciding with a reduction in Pd. In addition, due to differences in CP composition between pregnancy-related tissues and maternal body, Pd by itself may not be the best measurement criteria for the estimation of EAA requirement in pregnant sows. The proposed model also captures the negative maternal Pd that occurs in late gestation and indicates that litter size influences maternal tissue mobilization more than parity. The model predicts that the EAA requirements in early and mid-gestation are 75, 55 and 50% lower for primiparous sows than parity 2, 3 and 4+ sows, respectively, which suggest the potential benefits of parity segregated feeding.

Mechanism of the Transition From In-Plane Buckling to Helical Buckling for a Stiff Nanowire on an Elastomeric Substrate

2016 ◽  
Vol 83 (4) ◽  
Author(s):  
Youlong Chen ◽  
Yong Zhu ◽  
Xi Chen ◽  
Yilun Liu
Keyword(s):  
High Performance ◽  
Three Dimensional ◽  
Stretchable Electronics ◽  
Buckling Mode ◽  
Design And Optimization ◽  
Out Of Plane ◽  
Plane Direction ◽  
Plane Displacement ◽  
Helical Buckling ◽  
Selection Of

In this work, the compressive buckling of a nanowire partially bonded to an elastomeric substrate is studied via finite-element method (FEM) simulations and experiments. The buckling profile of the nanowire can be divided into three regimes, i.e., the in-plane buckling, the disordered buckling in the out-of-plane direction, and the helical buckling, depending on the constraint density between the nanowire and the substrate. The selection of the buckling mode depends on the ratio d/h, where d is the distance between adjacent constraint points and h is the helical buckling spacing of a perfectly bonded nanowire. For d/h > 0.5, buckling is in-plane with wavelength λ = 2d. For 0.27 < d/h < 0.5, buckling is disordered with irregular out-of-plane displacement. While, for d/h < 0.27, buckling is helical and the buckling spacing gradually approaches to the theoretical value of a perfectly bonded nanowire. Generally, the in-plane buckling induces smaller strain in the nanowire, but consumes the largest space. Whereas the helical mode induces moderate strain in the nanowire, but takes the smallest space. The study may shed useful insights on the design and optimization of high-performance stretchable electronics and three-dimensional complex nanostructures.

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