Strain-Rate Effects in the Propagation of Torsional Plastic Waves

1966 ◽  
Vol 33 (4) ◽  
pp. 917-923 ◽  
Author(s):  
W. E. Baker ◽  
C. H. Yew
Keyword(s):  
Strain Rate ◽  
Shear Strain ◽  
Cross Sections ◽  
Pure Copper ◽  
High Rate ◽  
Strain Rate Effects ◽  
Rate Dependent ◽  
Dependent Theory ◽  
Lower Strain ◽  
Rate Effects

A new method was developed for determining the dynamic stress-strain relationships of materials subjected to high rate of torsional loading. In addition, an investigation of propagation of torsional plastic waves in a long tube was conducted. Commercially pure copper was used throughout both investigations. In the material property studies, shear strains up to 20 percent and shear strain rates to 2100/sec were obtained. The results indicated that copper exhibits significantly lower strain-rate effects than those previously obtained by the longitudinal loading method. In the studies of plastic wave propagation, shear strain-time records at several cross sections along the tube were compared with computed results obtained from the strain-rate-independent and strain-rate-dependent theories. It is concluded that the computed results based on the strain-rate-dependent theory give better agreement with the experiments.

scholarly journals Colloidal gels under shear: Strain rate effects

2013 ◽  
Author(s):  
N. Koumakis ◽  
P. Ballesta ◽  
R. Besseling ◽  
W. C. K. Poon ◽  
J. F. Brady ◽  
...  
Keyword(s):  
Strain Rate ◽  
Shear Strain ◽  
Shear Strain Rate ◽  
Colloidal Gels ◽  
Strain Rate Effects ◽  
Rate Effects

scholarly journals Review of Strain Rate Effects of Fiber-Reinforced Polymer Composites

Polymers ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2839
Author(s):  
Lulu Ma ◽  
Feng Liu ◽  
Dongyu Liu ◽  
Yaolu Liu
Keyword(s):  
Strain Rate ◽  
Numerical Models ◽  
Fiber Reinforced Polymer ◽  
Fiber Reinforced ◽  
Strain Rate Effects ◽  
Frp Composites ◽  
Rate Dependent ◽  
Reinforced Polymer ◽  
Fiber Reinforced Polymer Composites ◽  
Rate Effects

The application of fiber-reinforced polymer (FRP) composites is gaining increasing popularity in impact-resistant devices, automotives, biomedical devices and aircraft structures due to their high strength-to-weight ratios and their potential for impact energy absorption. Impact-induced high loading rates can result in significant changes of mechanical properties (e.g., elastic modulus and strength) before strain softening occurs and failure characteristics inside the strain localization zone (e.g., failure mechanisms and fracture energy) for fiber-reinforced polymer composites. In general, these phenomena are called the strain rate effects. The underlying mechanisms of the observed rate-dependent deformation and failure of composites take place among multiple length and time scales. The contributing mechanisms can be roughly classified as: the viscosity of composite constituents (polymer, fiber and interfaces), the rate-dependency of the fracture mechanisms, the inertia effects, the thermomechanical dissipation and the characteristic fracture time. Numerical models, including the viscosity type of constitutive models, rate-dependent cohesive zone models, enriched equation of motion and thermomechanical numerical models, are useful for a better understanding of these contributing factors of strain rate effects of FRP composites.

Transient Response of Strain Rate Dependent Composite Plates Using Finite Difference Method

2010 ◽  
Author(s):  
M. M. Shokrieh ◽  
A. Karamnejad
Keyword(s):  
Finite Difference ◽  
Strain Rate ◽  
Composite Plate ◽  
Plate Theory ◽  
Static Model ◽  
Laminated Plate ◽  
Difference Model ◽  
Strain Rate Effects ◽  
Rate Dependent ◽  
Rate Effects

In the present work, the response of laminated composite plate under dynamic loading is investigated using a macro-mechanical approach by use of a finite difference model which accounts for geometric nonlinearity and strain rate effects. Coupled nonlinear equations of motion of a laminated plate based on classical laminated plate theory (CLPT) and first-order shear deformation laminated plate theory (FSDT) are derived and reduced to nonlinear ordinary differential equations in time domain by finite difference approximations for displacements. Newmark time integration scheme in association with Newton-Raphson iteration method is applied to solve the system of nonlinear equations. Sudden material property degradation rules are modified to account for strain rate effects. A progressive damage model is developed based on the modified material property degradation rules and Hashin-type failure criteria and added to a finite difference model. The model is implemented into a computer code in Mathematica 6. The model is validated by comparison of the present results with those are available in the literature. The effects of transverse shear strain are studied by comparison of the results obtained using CLPT and FSDT. In order to investigate the strain rate effects, a clamped Glass/Epoxy composite plate subjected to a triangular load is considered. Results for static model, in which the mechanical properties are constant and dynamic model which has strain rate dependent mechanical properties are compared for various stacking sequences and load magnitudes. The results show that the deflections are overestimated by static model and the difference between static and dynamic models results increases with the magnitude of load. Furthermore, the variation trend of maximum displacement with stacking sequence is the same for both material models.

Strain Rate Effects on Concrete and Reinforcements, and their Contributions to Structures

1985 ◽  
Vol 64 ◽  
Author(s):  
Jin-ichi Takeda
Keyword(s):  
Reinforced Concrete ◽  
Strain Rate ◽  
Concrete Structures ◽  
High Rate ◽  
Reinforced Concrete Structures ◽  
Fracture Criteria ◽  
Dynamic Design ◽  
Strain Rate Effects ◽  
Rate Effects ◽  
Brittle Fractures

ABSTRACTThis paper deals with the rate effects on concrete and reinforcements, especially unfavorable effects for the dynamic design of concrete or reinforced concrete structures. The rate effects on concrete are divided into two effects, the rate effect on stress-strain relations and that on fracture criteria of concrete which bringsabout occasionally the unfavorable and brittle fractures of concrete and reinforced concrete structures.It is also described that the brittle fractures are usually caused by the rapid propagation of cracks generated in concrete under the high rate loadings, which can be said to be one of the rate effects on concrete.

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