A statistical model for the time dependent failure of unidirectional composite materials under local elastic load-sharing among fibers

1983 ◽  
Vol 18 (1) ◽  
pp. 193-215 ◽  
Author(s):  
S.L. Phoenix ◽  
L-J. Tierney
Keyword(s):  
Composite Materials ◽  
Statistical Model ◽  
Load Sharing ◽  
Unidirectional Composite ◽  
Time Dependent ◽  
Elastic Load ◽  
Dependent Failure

Determination of In-plane Shear Strength of Unidirectional Composite Materials Using the Off-axis Three-point Flexure and Off-axis Tensile Tests

2010 ◽  
Vol 44 (21) ◽  
pp. 2487-2507 ◽  
Author(s):  
G. Vargas ◽  
F. Mujika
Keyword(s):  
Shear Strength ◽  
Composite Materials ◽  
Tensile Tests ◽  
Unidirectional Composite ◽  
Point Of View ◽  
Experimental Point ◽  
Plane Shear ◽  
Lift Off ◽  
Flexure Test

The aim of this work is to compare from an experimental point of view the determination of in-plane shear strength of unidirectional composite materials by means of two off-axis tests: three-point flexure and tensile. In the case of the off-axis three-point flexure test, the condition of small displacements and the condition of lift-off between the specimen and the fixture supports have been taken into account. Some considerations regarding stress and displacement fields are presented. The in-plane shear characterization has been performed on a carbon fiber reinforced unidirectional laminate with several fiber orientation angles: 10°, 20°, 30°, and 45°. Test conditions for both off-axis experimental methods, in order to ensure their applicability, are presented. Off-axis flexure test is considered more suitable than off-axis tensile test for the determination of in-plane shear strength.

Model of vibration in drilling into fibre-reinforced composite materials

2009 ◽  
Vol 223 (9) ◽  
pp. 1107-1114
Author(s):  
B W Huang
Keyword(s):  
Composite Materials ◽  
Vibration Amplitude ◽  
Time Dependent ◽  
Process Time ◽  
Drilling Process ◽  
Improve Product Quality ◽  
Analysis Model ◽  
Inhomogeneous Materials ◽  
Reinforced Composite ◽  
Twisted Beam

A model of the dynamic drill characteristics while drilling through fibre-reinforced composite materials (FRCMs) is investigated in this study. Anisotropic and inhomogeneous materials such as FRCMs, which are used to improve product quality, make it possible to improve production rate and avoid drill breakage. Such materials were used to study the dynamic characteristics of the drilling process. A theoretical analysis model for drilling composite materials is proposed. A pre-twisted beam is used to simulate the drill. A moving Winkler-type elastic foundation is used to approximate the drilling process time-dependent boundary. Numerical analysis indicates that the vibration amplitude changes significantly as the drill moves through composite material.

An asymmetrical dynamic model for bridging fiber pull-out of unidirectional composite materials

Meccanica ◽  
2011 ◽  
Vol 47 (5) ◽  
pp. 1247-1260 ◽  
Author(s):  
N. C. Lü ◽  
Y. H. Cheng ◽  
X. G. Li ◽  
J. Cheng
Keyword(s):  
Composite Materials ◽  
Dynamic Model ◽  
Unidirectional Composite ◽  
Pull Out

Dynamic Behavior of Aircraft Wings Modeled as Doubly-Tapered Composite Thin-Walled Beams

1999 ◽  
Author(s):  
Sungsoo Na ◽  
Liviu Librescu
Keyword(s):  
Composite Materials ◽  
Free Vibration ◽  
Dynamic Response ◽  
Dynamic Behavior ◽  
Transverse Shear ◽  
Dynamical Behavior ◽  
Time Dependent ◽  
Aircraft Wings ◽  
Helicopter Blades ◽  
Thin Walled

Abstract A study of the dynamical behavior of aircraft wings modeled as doubly-tapered thin-walled beams, made from advanced anisotropic composite materials, and incorporating a number of non-classical effects such as transverse shear, and warping inhibition is presented. The supplied numerical results illustrate the effects played by the taper ratio, anisotropy of constituent materials, transverse shear flexibility, and warping inhibition on free vibration and dynamic response to time-dependent external excitations. Although considered for aircraft wings, this analysis and results can be also applied to a large number of structures such as helicopter blades, robotic manipulator arms, space booms, tall cantilever chimneys, etc.

Experimental Study of Time-dependent Failure of High Strain Composites

2020 ◽  
Author(s):  
Kanthasamy Ubamanyu ◽  
Daniele Ghedalia ◽  
Armanj D. Hasanyan ◽  
Sergio Pellegrino
Keyword(s):  
Experimental Study ◽  
High Strain ◽  
Time Dependent ◽  
Dependent Failure

The Integrative Time-Dependent Modeling of the Reliability and Failure of the Causes of Drivers' Error Leading to Road Accidents

2015 ◽  
pp. 1279-1294
Author(s):  
Khashayar Hojjati-Emami ◽  
Balbir S. Dhillon ◽  
Kouroush Jenab
Keyword(s):  
Human Error ◽  
Time Dependent ◽  
Failure Rates ◽  
Road Accidents ◽  
Road Transportation ◽  
The Road ◽  
Representational Model ◽  
On The Road ◽  
The Moment ◽  
Dependent Failure

Nowadays, the human error is usually identified as the conclusive cause of investigations in road accidents. The human although is the person in control of vehicle until the moment of crash but it has to be understood that the human is under continued impact by various factors including road environment, vehicle and human's state, abilities and conduct. The current advances in design of vehicle and roads have been intended to provide drivers with extra comfort with less physical and mental efforts, whereas the fatigue imposed on driver is just being transformed from over-load fatigue to under-load fatigue and boredom. A representational model to illustrate the relationships between design and condition of vehicle and road as well as driver's condition and state on fatigue and the human error leading to accidents has been developed. Thereafter, the stochastic mathematical models based on time-dependent failure rates were developed to make prediction on the road transportation reliability and failure probabilities due to each cause (vehicle, road environment, human due to fatigue, and human due to non fatigue factors). Furthermore, the supportive assessment methodology and models to assess and predict the failure rates of driver due to each category of causes were developed and proposed.

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