Size effect in micro-scale cantilever beam bending

This work proposes an investigation on size effects in micro-scale splitting crack initiation and propagation and their consequences on the macro-scale structural behavior carbon-fiber reinforced polymers under transverse tension. Towards this goal, size effect tests were experimentally conducted on both notch-free [90]n composites and specimens with different notch types under three-point bending. The mechanical tests were followed by morphological studies to identify the micro-scale damage mechanisms and their evolution. The results clearly show that splitting crack initiation in the transverse direction of composites not only happens at the fiber/matrix interface but also in the matrix. Moreover, the subsequent development of these damage mechanisms can depend on the structure size. This interesting phenomenon inherently leads to size-dependent structural behavior which can be described through Baznt’s Size Effect Laws. This study on the splitting crack initiation and propagation can provide unprecedented information for the calibration and validation of micromechanical models for the damage behavior of fiber composites at the microscale.

Download Full-text

The mechanical size effect as a mean-field breakdown phenomenon: Example of microscale single crystal beam bending

Acta Materialia ◽

10.1016/j.actamat.2009.11.031 ◽

2010 ◽

Vol 58 (5) ◽

pp. 1876-1886 ◽

Cited By ~ 65

Author(s):

Eralp Demir ◽

Dierk Raabe ◽

Franz Roters

Keyword(s):

Size Effect ◽

Single Crystal ◽

Mean Field ◽

Breakdown Phenomenon ◽

Beam Bending

Download Full-text

A COMSOL approach to the analysis of a micro-scale piezoelectric cantilever beam: The effect of dimension parameters on the eigen frequency

2017 Innovations in Power and Advanced Computing Technologies (i-PACT) ◽

10.1109/ipact.2017.8244969 ◽

2017 ◽

Author(s):

Amit Md. Estiaque Arefin ◽

Rifatul Mursalin ◽

Md. Emdadul Hoque

Keyword(s):

Cantilever Beam ◽

Micro Scale ◽

Piezoelectric Cantilever ◽

Eigen Frequency

Download Full-text

Characterization of the Fluidity of the Ultrasonic Plasticized Polymer Melt by Spiral Flow Testing under Micro-Scale

Polymers ◽

10.3390/polym11020357 ◽

2019 ◽

Vol 11 (2) ◽

pp. 357 ◽

Cited By ~ 4

Author(s):

Bingyan Jiang ◽

Yang Zou ◽

Tao Liu ◽

Wangqing Wu

Keyword(s):

Size Effect ◽

Amorphous Polymer ◽

Polymer Melt ◽

Mold Temperature ◽

Polyamide 66 ◽

Spiral Flow ◽

Crystalline Polymers ◽

Micro Scale ◽

Flow Length ◽

And Control

The fluidity of a molten polymer plasticized by ultrasonic vibration was characterized by spiral flow testing based on an Archimedes spiral mold with microchannels. Mold inserts with various channel depths from 250 to 750 µm were designed and fabricated to represent the size effect under micro-scale. The effect of ultrasonic plasticizing parameters and the mold temperature on the flow length was studied to determine the rheological nature of polymers and control parameters. The results showed that the flow length decreased with reduced channel depth due to the size effect. By increasing ultrasonic amplitude, ultrasonic action time, plasticizing pressure, and mold temperature, the flow length could be significantly increased for both the amorphous polymer polymethyl methacrylate (PMMA) and the semi-crystalline polymers polypropylene (PP) and polyamide 66 (PA66). The enhanced fluidity of the ultrasonic plasticized polymer melt could be attributed to the significantly reduced shear viscosity.

Download Full-text