A Fractographic Study of PE, PP Self-reinforced Composites in Quasi-static Loading Conditions

Author(s):  
M. Sharan Chandran ◽  
K. Padmanabhan
2018 ◽  
Vol 183 ◽  
pp. 02022
Author(s):  
Vincent Grolleau ◽  
Vincent Lafilé ◽  
Christian C. Roth ◽  
Bertrand Galpin ◽  
Laurent Mahéo ◽  
...  

Among all other stress states achievable under plane stress conditions, the lowest ductility is consistently observed for plane strain tension. For static loading conditions, V-bending of small sheet coupons is the most reliable way of characterising the strain to fracture for plane strain tension. Different from conventional notched tension specimens, necking is suppressed during V-bending which results in a remarkably constant stress state all the way until fracture initiation. The present DYMAT talk is concerned with the extension of the V-bending technique from low to high strain rate experiments. A new technique is designed with the help of finite element simulations. It makes use of modified Nakazima specimens that are subjected to V-bending. Irrespective of the loading velocity, plane strain tension conditions are maintained throughout the entire loading history up to fracture initiation. Experiments are performed on specimens extracted from aluminum 2024-T3 and dual phase DP450 steel sheets. The experimental program includes quasi static loading conditions which are achieved on a universal testing machine. In addition, high strain rate experiments are performed using a specially-designed drop tower system. In all experiments, images are acquired with two cameras to determine the surface strain history through stereo Digital Image Correlation (DIC). The experimental observations are discussed in detail and also compared with the numerical simulations to validate the proposed experimental technique


Polimery ◽  
2012 ◽  
Vol 57 (2) ◽  
pp. 87-94 ◽  
Author(s):  
JAN RYBNICEK ◽  
RALF LACH ◽  
WOLFGANG GRELLMANN ◽  
MONIKA LAPCIKOVA ◽  
MIROSLAV SLOUF ◽  
...  

2013 ◽  
Vol 569-570 ◽  
pp. 1076-1084 ◽  
Author(s):  
Kevin Soobbarayen ◽  
Sébastien Besset ◽  
Jean Jacques Sinou

This work proposes to study the effects of physical parameters and loading conditions on both dynamic and acoustic responses of a brake system subjected to squeal. A simplified brake system model composed of a disc and a pad is investigated. The friction interface is modeled by introducing linear and non-linear stiffnesses at several local nodes to model contact. The classical Coulomb law is applied to model friction and the friction coefficient is assumed to be constant. A stability analysis of this system is performed with respect to the friction coefficient and the hydraulic brake pressure. Then self-excited vibrations are investigated for two cases of loading conditions: static loading and ramp loading. Time responses for these cases are significantly different: the case with ramp loading presents higher amplitude of velocity than the static loading case. For the case with ramp loading, the spectrum analysis performed by the Continuous Wavelet Transform, shows the appearance of the fundamental frequencies of unstable modes but also their harmonics and combinations frequencies. Sound pressures radiated during squeal event present different peculiar patterns of directivity for both cases and for a progressive load, the levels are significantly higher.


2010 ◽  
Vol 133-134 ◽  
pp. 459-465 ◽  
Author(s):  
Rosalba Ferrari ◽  
Mattia Facheris ◽  
Egidio Rizzi

The Paderno d’Adda Bridge is a marvellous riveted iron viaduct with a doubly-built-in parabolic arch that crosses the river Adda near Milano, between Paderno d’Adda (Lecco province) and Calusco d’Adda (Bergamo province), in Lombardia, northern Italy. It was completed in 1889 by the “Società Nazionale delle Officine di Savigliano” (SNOS). In this work, following a previous contribution to the last SAHC08 Conference (Ferrari and Rizzi 2008), a complete FEM model of the bridge is presented, in the attempt of querying the performance of the structure at design stage. Several static loading conditions have been carried-out in the elastic range and results have been compared to those available in the original SNOS Report (1889), with remarkable correspondence.


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