scholarly journals Unraveling the Mechanics of Thermal Stress Weathering: Rate‐Effects, Size‐Effects, and Scaling Laws

2019 ◽  
Vol 124 (12) ◽  
pp. 3304-3328 ◽  
Author(s):  
Babak Ravaji ◽  
Víctor Alí‐Lagoa ◽  
Marco Delbo ◽  
Justin W. Wilkerson
Keyword(s):  
Thermal Stress ◽  
Size Effects ◽  
Scaling Laws ◽  
Weathering Rate ◽  
Rate Effects

Static and Dynamic Collapse Characteristics of Scale Model Corrugated Tubular Sections

1975 ◽  
Vol 97 (4) ◽  
pp. 357-362 ◽  
Author(s):  
P. H. Thornton
Keyword(s):  
Scaling Laws ◽  
Dynamic Testing ◽  
Plastic Hinge ◽  
Rate Sensitivity ◽  
Scale Model ◽  
Complex Deformation ◽  
Collapse Characteristics ◽  
Rate Effects ◽  
Deformation Processes ◽  
Tubular Sections

The collapse load of a series of scale model, corrugated tubular sections was determined, both by quasi-static and by dynamic testing. Provided that the material from which the models are made is identical to that of the full size component, then the scaling laws for structures undergoing complex deformation processes will be obeyed. The dynamic collapse response, which occurred by the operation of a plastic hinge mechanism, is governed by the strain rate sensitivity of the material; structural rate effects do not affect the collapse process.

scholarly journals Mechanical Response of Hollow Metallic Nanolattices: Combining Structural and Material Size Effects

2015 ◽  
Vol 82 (7) ◽  
Author(s):  
L. C. Montemayor ◽  
J. R. Greer
Keyword(s):  
Mechanical Properties ◽  
Yield Strength ◽  
Relative Density ◽  
Size Effects ◽  
Scaling Laws ◽  
Tube Wall ◽  
Three Dimensional ◽  
Cellular Solids ◽  
Tube Wall Thickness ◽  
Strength And Stiffness

Ordered cellular solids have higher compressive yield strength and stiffness compared to stochastic foams. The mechanical properties of cellular solids depend on their relative density and follow structural scaling laws. These scaling laws assume the mechanical properties of the constituent materials, like modulus and yield strength, to be constant and dictate that equivalent-density cellular solids made from the same material should have identical mechanical properties. We present the fabrication and mechanical properties of three-dimensional hollow gold nanolattices whose compressive responses demonstrate that strength and stiffness vary as a function of geometry and tube wall thickness. All nanolattices had octahedron geometry, a constant relative density, ρ ∼ 5%, a unit cell size of 5–20 μm, and a constant grain size in the Au film of 25–50 nm. Structural effects were explored by increasing the unit cell angle from 30 deg to 60 deg while keeping all other parameters constant; material size effects were probed by varying the tube wall thickness, t, from 200 nm to 635 nm, at a constant relative density and grain size. In situ uniaxial compression experiments revealed an order of magnitude increase in yield stress and modulus in nanolattices with greater lattice angles, and a 150% increase in the yield strength without a concomitant change in modulus in thicker-walled nanolattices for fixed lattice angles. These results imply that independent control of structural and material size effects enables tunability of mechanical properties of three-dimensional architected metamaterials and highlight the importance of material, geometric, and microstructural effects in small-scale mechanics.

scholarly journals Mechanical Properties and Weibull Scaling Laws of Unknown Spider Silks

Molecules ◽  
2020 ◽  
Vol 25 (12) ◽  
pp. 2938
Author(s):  
Gabriele Greco ◽  
Nicola M. Pugno
Keyword(s):  
Mechanical Properties ◽  
Size Effects ◽  
Spider Silk ◽  
Scaling Laws ◽  
Statistical Investigation ◽  
Strain Rates ◽  
Cupiennius Salei ◽  
Weibull Parameters ◽  
Spider Silks

Spider silks present extraordinary mechanical properties, which have attracted the attention of material scientists in recent decades. In particular, the strength and the toughness of these protein-based materials outperform the ones of many man-made fibers. Unfortunately, despite the huge interest, there is an absence of statistical investigation on the mechanical properties of spider silks and their related size effects due to the length of the fibers. Moreover, several spider silks have never been mechanically tested. Accordingly, in this work, we measured the mechanical properties and computed the Weibull parameters for different spider silks, some of them unknown in the literature. We also measured the mechanical properties at different strain rates for the dragline of the species Cupiennius salei. For the same species, we measured the strength and Weibull parameters at different fiber lengths. In this way, we obtained the spider silk scaling laws directly and according to Weibull’s prediction. Both length and strain rates affect the mechanical properties of spider silk, as rationalized by Weibull’s statistics.

Siphon Flows in Stratified Coronal Loops

1994 ◽  
Vol 144 ◽  
pp. 185-187
Author(s):  
S. Orlando ◽  
G. Peres ◽  
S. Serio
Keyword(s):  
Heat Flux ◽  
Scaling Laws ◽  
Flow Model ◽  
Supersonic Flows ◽  
Coronal Loops ◽  
Characteristic Parameters

AbstractWe have developed a detailed siphon flow model for coronal loops. We find scaling laws relating the characteristic parameters of the loop, explore systematically the space of solutions and show that supersonic flows are impossible for realistic values of heat flux at the base of the upflowing leg.

The reinforcing and rate effects of intracranial dopamine administration.

1986 ◽  
Author(s):  
Steven I. Dworkin ◽  
Nick E. Goeders ◽  
James E. Smith
Keyword(s):  
Rate Effects
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