scholarly journals Feature Size Effect on Formability of Multilayer Metal Composite Sheets under Microscale Laser Flexible Forming

Metals ◽  
2017 ◽  
Vol 7 (7) ◽  
pp. 275 ◽  
Author(s):  
Huixia Liu ◽  
Wenhao Zhang ◽  
Jenn-Terng Gau ◽  
Zongbao Shen ◽  
Youjuan Ma ◽  
...  
Keyword(s):  
Size Effect ◽  
Metal Composite ◽  
Feature Size ◽  
Flexible Forming ◽  
Multilayer Metal

Experimental Research on Laser-Shock Flexible Micro-Forming of Multilayer-Metal Composite Sheets

2017 ◽  
Vol 44 (7) ◽  
pp. 0702001
Author(s):  
Zhang Wenhao ◽  
Liu Huixia ◽  
Shen Zongbao ◽  
Zhang Guoce ◽  
Ma Youjuan ◽  
...  
Keyword(s):  
Experimental Research ◽  
Metal Composite ◽  
Laser Shock ◽  
Micro Forming ◽  
Multilayer Metal

Size effect in mesoscopic epitaxial ferroelectric structures: Increase of piezoelectric response with decreasing feature size

2002 ◽  
Vol 80 (17) ◽  
pp. 3195-3197 ◽  
Author(s):  
S. Bühlmann ◽  
B. Dwir ◽  
J. Baborowski ◽  
P. Muralt
Keyword(s):  
Size Effect ◽  
Piezoelectric Response ◽  
Feature Size

scholarly journals Modeling and analysis of temperature distribution in the multilayer metal composite structures in grinding

2017 ◽  
Vol 91 (9-12) ◽  
pp. 4055-4068 ◽  
Author(s):  
V. A. Pashnyov ◽  
D. Yu. Pimenov ◽  
I. N. Erdakov ◽  
M. S. Koltsova ◽  
T. Mikolajczyk ◽  
...  
Keyword(s):  
Temperature Distribution ◽  
Composite Structures ◽  
Metal Composite ◽  
Modeling And Analysis ◽  
Multilayer Metal

FE Analysis of Size Effect on Deformation Behavior of Metal Microtube Considering Surface Roughness in Flaring Test

2009 ◽  
Vol 623 ◽  
pp. 79-87 ◽  
Author(s):  
Mohammad Ali Mirzai ◽  
Kenichi Manabe
Keyword(s):  
Surface Roughness ◽  
Size Effect ◽  
Wall Thickness ◽  
Size Effects ◽  
Fe Analysis ◽  
Material Behavior ◽  
Test Results ◽  
Feature Size ◽  
Analysis And Design ◽  
Smoothing Process

Reliable test results that show the material characteristics of a micromaterial are necessary for the accurate analysis and design of microforming processes. The size effects in the microforming are predicted to have a significant impact on the material behavior. Two size effects are explored in metallic materials. One is the grain size effect, and the other is the feature/specimen size effect. In this study, the feature size effect on the smoothing process with the consideration of tool surface roughness is investigated numerically for metal microtubes by the flaring test. Stainless-steel (SUS 316L) microtubes with the same outer diameter of 500 μm and different wall thicknesses of 50, 25 and 10 μm were used in the FE analysis to study the feature size effect on the microscale by the flaring test. The surface roughnesses of the inner and outer surfaces of the microtube, as well as the surface asperity of the conical tool, were modeled in the cyclic concave-convex configuration. It is found, in the flaring test with using rough and fine tools, that the smoothing process on the inner surface of the microtube (ISM), as well as the plastic strain in the wall thickness of microtube, is affected owing to the rigidity of the microtube, which decreases as the wall thickness of the microtube decreases. These results suggest that the feature size affects the flaring test results for the metal microtube.

Scaling of Strength of Metal-Composite Joints—Part III: Numerical Simulation

2013 ◽  
Vol 80 (5) ◽  
Author(s):  
Qiang Yu ◽  
Zdeněk P. Bažant ◽  
Jia-Liang Le
Keyword(s):  
Size Effect ◽  
Fracture Energy ◽  
Peak Load ◽  
Adhesive Layer ◽  
Cohesive Crack ◽  
Crack Model ◽  
Mixed Mode Fracture ◽  
Stress Profile ◽  
Metal Composite ◽  
Cohesive Stress

The size effect in the failure of a hybrid adhesive joint of a metal with a fiber-polymer composite, which has been experimentally demonstrated and analytically formulated in preceding two papers, is here investigated numerically. Cohesive finite elements with a mixed-mode fracture criterion are adopted to model the adhesive layer in the metal-composite interface. A linear traction-separation softening law is assumed to describe the damage evolution at debonding in the adhesive layer. The results of simulations agree with the previously measured load-displacement curves of geometrically similar hybrid joints of various sizes, with the size ratio of 1:4:12. The effective size of the fracture process zone is identified from the numerically simulated cohesive stress profile at the peak load. The fracture energy previously identified analytically by fitting the experimentally observed size effect curves agrees well with the fracture energy of the cohesive crack model obtained numerically by optimal fitting of the test data.

Scaling of Strength of Metal-Composite Joints—Part I: Experimental Investigation

2009 ◽  
Vol 77 (1) ◽  
Author(s):  
Qiang Yu ◽  
Zdeněk P. Bažant ◽  
John Bayldon ◽  
Jia-Liang Le ◽  
Ferhun C. Caner ◽  
...  
Keyword(s):  
Size Effect ◽  
Peak Load ◽  
Maximum Load ◽  
Lap Joints ◽  
Interface Fracture ◽  
Metal Composite ◽  
Interface Failure ◽  
Interface Shear ◽  
Nominal Strength ◽  
The University

Knowledge of the size effect on the strength of hybrid bimaterial joints of steel and fiber composites is important for new designs of large lightweight ships, large fuel-efficient aircrafts, and lightweight crashworthy automobiles. Three series of scaled geometrically similar specimens of symmetric double-lap joints with a rather broad size range (1:12) are manufactured. The specimens are tested to failure under tensile displacement-controlled loading, and at rates that ensure the peak load to be reached within approximately the same time. Two series, in which the laminate is fiberglass G-10/FR4, are tested at Northwestern University, and the third series, in which the laminate consists of NCT 301 carbon fibers, is tested at the University of Michigan. Except for the smallest specimens in test series I, all the specimens fail by propagation of interface fracture initiating at the bimaterial corner. All the specimens fail dynamically right after reaching the maximum load. This observation confirms high brittleness of the interface failure. Thus, it is not surprising that the experiments reveal a marked size effect, which leads to a 52% reduction in nominal interface shear strength. As far as the inevitable scatter permits it to see, the experimentally observed nominal strength values agree with the theoretical size effect derived in Part II of this study, where the size exponent of the theoretical large-size asymptotic power law is found to be −0.459 for series I and II, and −0.486 for series III.

Scaling of Strength of Metal-Composite Joints—Part II: Interface Fracture Analysis

2009 ◽  
Vol 77 (1) ◽  
Author(s):  
Jia-Liang Le ◽  
Zdeněk P. Bažant ◽  
Qiang Yu
Keyword(s):  
Size Effect ◽  
Crack Length ◽  
Interface Crack ◽  
Fiber Composite ◽  
Preceding Paper ◽  
Cohesive Crack ◽  
Crack Model ◽  
Metal Composite ◽  
Composite Joint ◽  
Nominal Strength

The effect of the size of hybrid metal-composite joint on its nominal strength, experimentally demonstrated in the preceding paper (part I), is modeled mathematically. Fracture initiation from a reentrant corner at the interface of a metallic bar and a fiber composite laminate sheet is analyzed. The fracture process zone (or cohesive zone) at the corner is approximated as an equivalent sharp crack according to the linear elastic fracture mechanics (LEFM). The asymptotic singular stress and displacement fields surrounding the corner tip and the tip of an interface crack emanating from the corner tip are calculated by means of complex potentials. The singularity exponents of both fields are generally complex. Since the real part of the stress singularity exponent for the corner tip is not −12, as required for finiteness of the energy flux into the tip, the interface crack propagation criterion is based on the singular field of the interface crack considered to be embedded in a more remote singular near-tip field of the corner from which, in turn, the boundaries are remote. The large-size asymptotic size effect on the nominal strength of the hybrid joint is derived from the LEFM considering the interface crack length to be much smaller than the structure size. The deviation from LEFM due to finiteness of the interface crack length, along with the small-size asymptotic condition of quasiplastic strength, allows an approximate general size effect law for hybrid joints to be derived via asymptotic matching. This law fits closely the experimental results reported in the preceding paper. Numerical validation according to the cohesive crack model is relegated to a forthcoming paper.

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