Techno Press


Steel and Composite Structures   Volume 18, Number 6, June 2015, pages 1465-1478
DOI: http://dx.doi.org/10.12989/scs.2015.18.6.1465
 
Dynamic load concentration caused by a break in a Lamina with viscoelastic matrix
Arash Reza, Hamid M. Sedighi and Mahdi Soleimani

 
Abstract     [Full Text]
    The effect of cutting off fibers on transient load in a polymeric matrix composite lamina was studied in this paper. The behavior of fibers was considered to be linear elastic and the matrix behavior was considered to be linear viscoelastic. To model the viscoelastic behavior of matrix, a three parameter solid model was employed. To conduct this research, finite difference method was used. The governing equations were obtained using Shear-lag theory and were solved using boundary and initial conditions before and after the development of break. Using finite difference method, the governing integro-differential equations were developed and normal stress in the fibers is obtained. Particular attention is paid the dynamic overshoot resulting when the fibers are suddenly broken. Results show that considering viscoelastic properties of matrix causes a decrease in dynamic load concentration factor and an increase in static load concentration factor. Also with increases the number of broken fibers, trend of increasing load concentration factor decreases gradually. Furthermore, the overshoot of load in fibers adjacent to the break in a polymeric matrix with high transient time is lower than a matrix with lower transient time, but the load concentration factor in the matrix with high transient time is lower.
 
Key Words
    viscoelasticity; load concentration factor; transient stress; unidirectional lamina; finite difference method; break
 
Address
(1) Arash Reza:
Department of Mechanical Engineering, Ahvaz Branch, Islamic Azad University, Ahvaz, Iran;
(2) Hamid M. Sedighi:
Mechanical Engineering Department, Faculty of Engineering, Shahid Chamran University of Ahvaz, Ahvaz, Iran;
(3) Mahdi Soleimani:
Department of Mechanical Engineering, Shoushtar Branch, Islamic Azad University, Shoushtar, Iran.
 

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