Open Access. Powered by Scholars. Published by Universities.®

Mechanical Engineering Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 5 of 5

Full-Text Articles in Mechanical Engineering

Progressive Damage In Stitched Composites Under Impact Loading, Kwek Tze Tan, N. Watanabe, A. Yoshimura, Y. Iwahori, T. Ishikawa Aug 2011

Progressive Damage In Stitched Composites Under Impact Loading, Kwek Tze Tan, N. Watanabe, A. Yoshimura, Y. Iwahori, T. Ishikawa

Mechanical Engineering Faculty Research

Damage in carbon fibre reinforced plastics (CFRP) due to impact loading is an extremely complex phenomenon that comprises of multiple failure mechanisms like intra-laminar matrix cracks, interlaminar delamination, fibre pull-out and fibre fracture. In stitched composites, impact damage behavior is further complicated by the presence of through-thickness stitching [1, 2], which not only favorably increases mode I/II interlaminar strength [3, 4], but also inevitably creates geometrical defects like weak resin-rich pockets around stitch threads and misalignment of in-plane fibres. Computational modeling has been used to simulate progressive damage effectively [5]. However, the complexity of impact damage progression in stitched composites …


Enabling And Understanding Failure Of Engineering Structures Using The Technique Of Cohesive Elements, H. Jiang, Xiaosheng Gao, T. S. Srivatsan Feb 2011

Enabling And Understanding Failure Of Engineering Structures Using The Technique Of Cohesive Elements, H. Jiang, Xiaosheng Gao, T. S. Srivatsan

Mechanical Engineering Faculty Research

In this paper, we describe a cohesive zone model for the prediction of failure of engineering solids and/or structures. A damage evolution law is incorporated into a three-dimensional, exponential cohesive law to account for material degradation under the influence of cyclic loading. This cohesive zone model is implemented in the finite element software ABAQUS through a user defined subroutine. The irreversibility of the cohesive zone model is first verified and subsequently applied for studying cyclic crack growth in specimens experiencing different modes of fracture and/or failure. The crack growth behavior to include both crack initiation and crack propagation becomes a …


Influence Of Stitch Density And Stitch Thread Thickness On Compression After Impact Strength Of Stitched Composites, Kwek Tze Tan, N. Watanabe, Y. Iwahori, T. Ishikawa Jan 2011

Influence Of Stitch Density And Stitch Thread Thickness On Compression After Impact Strength Of Stitched Composites, Kwek Tze Tan, N. Watanabe, Y. Iwahori, T. Ishikawa

Mechanical Engineering Faculty Research

This study aims to investigate the influence of stitch density and stitch thread thickness on compression after impact (CAI) strength of stitched composites. Unstitched laminated composites and specimens stitched with varying stitch density and stitch thread thickness are subjected to impact damage and then compressive loading. It is shown that stitched composites have higher CAI strength than unstitched counterpart due to smaller impact-induced delamination area, where local buckling occurs during compressive failure. However, it is revealed that the effectiveness of stitching in suppressing delamination growth and inhibiting sublaminate buckling under compressive loading is intimately related to stitch density. It is …


Atomic Friction Studied By Modeling The Buried Inteface, Yalin Dong, Ashlie Martini, Qunyang Li, Robert W. Carpick Jan 2011

Atomic Friction Studied By Modeling The Buried Inteface, Yalin Dong, Ashlie Martini, Qunyang Li, Robert W. Carpick

Mechanical Engineering Faculty Research

Molecular dynamics simulation is carried out to model the single-asperity friction in atomic force microscope experiments. Superlubricity is achieved through misalignment between the AFM tip and substrate. Direct observation of the buried interface reveals that incommensurability-induced inhomogeneous shear stress can cause ultra-low atomic scale friction.


A New Look At Optimum Design For Convecting-Radiating Annular Fins Of Trapezoidal Profile, Benjamin T.F. Chung Jan 2011

A New Look At Optimum Design For Convecting-Radiating Annular Fins Of Trapezoidal Profile, Benjamin T.F. Chung

Mechanical Engineering Faculty Research

This paper deals with a controversial problem in answering the question “Does the optimum fin design always exist? If not, what are the optimization ranges and limitations?” These authors employ a general example of convecting-radiating trapezoidal annular fin with heat transfer at the tip and wall resistance at the interface. The present results indicate that the answer to the above first question is negative. The ranges of fin optimum design under different thermal and physical conditions are proposed. The effects of Biot number, radiation number, the heat loss at the tip, fin profile and overall wall resistance on fin optimization …