Buckling Evolution of Microelectromechanical Structures

1998 ◽  
Vol 518 ◽  
Author(s):  
Xin Zhang ◽  
Tong-Yi Zhang ◽  
Yitshak Zohar
Keyword(s):  
Theoretical Analysis ◽  
Local Buckling ◽  
Experimental Results ◽  
Mode I ◽  
Mode Ii ◽  
Mode Iii ◽  
Sacrificial Layers

AbstractThis study reports in-situ observations of the buckling evolution of microelectromechanical structures during etching of their underneath sacrificial layers. As the etching went on, the buckling pattern evolved from mode I, the sinusoidal half-waves, to mode II, the constrained sinusoidal half-waves, to mode III, the conventional mode, and finally to mode IV, the blister- like local buckling. Closed formulae were derived from theoretical analysis, and the experimental results agreed well with the theoretical ones.

In-situ observation of microscopic damage in adhesively bonded CFRP joints under mode I and mode II loading

2019 ◽  
Vol 227 ◽  
pp. 111330 ◽  
Author(s):  
Sota Oshima ◽  
Akinori Yoshimura ◽  
Yoshiyasu Hirano ◽  
Toshio Ogasawara ◽  
Kwek-Tze Tan
Keyword(s):  
Mode I ◽  
Mode Ii ◽  
In Situ Observation ◽  
Adhesively Bonded ◽  
Microscopic Damage ◽  
Mode Ii Loading

Stress Intensity Factors for Cracks Emanating from a Notch under Shear-Mode Loading

2018 ◽  
Vol 774 ◽  
pp. 48-53
Author(s):  
Jana Horníková ◽  
Pavel Šandera ◽  
Stanislav Žák ◽  
Jaroslav Pokluda
Keyword(s):  
Stress Intensity ◽  
Critical Length ◽  
Shear Mode ◽  
Mode I ◽  
Mode Ii ◽  
Mode Iii ◽  
Loading Mode ◽  
Notch Stress ◽  
Notch Geometry ◽  
Mode Ii Loading

The influence of the notch geometry on the stress intensity factor at the front of the emanating cracks is well known for the opening loading mode. The critical length of the crack corresponding to a vanishing of the influence of the notch stress concentration can be approximately expressed by the formula aI,c = 0.5ρ(d/ρ)1/3, where d and ρ are the depth and radius of the notch, respectively. The aim of the paper was to find out if this formula could be, at least nearly, applicable also to the case of shear mode loading. The related numerical calculations for mode II and III loading were performed using the ANSYS code for various combinations of notch depths and crack lengths in a cylindrical specimen with a circumferential U-notch. The results revealed that, for mode II loading, the critical length was much higher than that predicted by the formula for mode I loading. On the other hand, the critical lengths for mode I and mode III were found to be nearly equal.

A Study on Thermal Fracture Processing Models Applied to Glass Substrate Cutting

2011 ◽  
Vol 264-265 ◽  
pp. 1252-1257 ◽  
Author(s):  
Kuo Cheng Huang ◽  
Min Wei Hung ◽  
Shih Feng Tseng ◽  
Chi Hung Hwang
Keyword(s):  
Fracture Mechanics ◽  
Weight Function ◽  
Glass Substrate ◽  
Thermal Stresses ◽  
Local Buckling ◽  
Brittle Materials ◽  
Mode I ◽  
Mode Ii ◽  
Thermal Fracture ◽  
Mode Ii Fracture

Thermal fracture-cutting technology (TFCT) for brittle materials has become the main technology for LCD glass substrate cutting to meet the low residual thermal stresses requirement. Based on the thermal weight function principle of fracture mechanics, this paper presents thermal weight function distributions for the mode-I and mode-II fracture model, and the fracture phenomenon under a variety of cutting paths, such as tilt crack, split crack, twist crack, and local buckling.

Fracture characteristics of wood under mode I, mode II and mode III loading

2002 ◽  
Vol 82 (17-18) ◽  
pp. 3289-3298 ◽  
Author(s):  
Klaus Frühmann ◽  
Alexander Reiterer ◽  
Elmar K. Tschegg ◽  
Stefanie S. Stanzl-tschegg
Keyword(s):  
Mode I ◽  
Mode Ii ◽  
Mode Iii ◽  
Fracture Characteristics

Three-Dimensional Mode Separation to Obtain Stress Intensity Factors

2006 ◽  
Author(s):  
Pei Gu ◽  
R. J. Asaro
Keyword(s):  
Stress Intensity ◽  
Crack Propagation ◽  
Stress Intensity Factors ◽  
Three Dimensional ◽  
Integral Approach ◽  
Mode I ◽  
Mode Ii ◽  
Intensity Factors ◽  
Mode Iii ◽  
Mode Separation

For mixed-mode loading at a crack tip under small-scale yielding condition, mode I, mode II and mode III stress intensity factors control the crack propagation. This paper discusses three-dimensional mode separation to obtain the three stress intensity factors using the interaction integral approach. The 2D interaction integral approach to obtain mode I and mode II stress intensity factors is derived to 3D arbitrary crack configuration for mode I, mode II and mode III stress intensity factors. The method is implemented in a finite element code using domain integral method and numerical examples show good convergence for the domains around the crack tip. A complete solution for the three stress intensity factors is obtained for a bar with inclined crack face to the cross-section from numerical calculations. The solution for the bar is plotted into curves in terms of a set of non-dimensional parameters for practical engineering purpose. From the solution, mode mixity along the crack front and its implication to the direction of crack propagation is discussed.

Evaluation of Generalized MTS Criterion for Mixed-Mode Fracture of Polyurethane Materials

2013 ◽  
Vol 577-578 ◽  
pp. 117-120 ◽  
Author(s):  
Radu Negru ◽  
Liviu Marşavina ◽  
Hannelore Filipescu
Keyword(s):  
Mixed Mode ◽  
Full Range ◽  
Experimental Results ◽  
Mode I ◽  
Mode Ii ◽  
Mixed Mode Fracture ◽  
Pure Mode ◽  
Bend Specimen ◽  
Mode Fracture ◽  
Fracture Tests

Using the asymmetric semi-circular bend specimen (ASCB) a set of mixed-mode fracture tests were carried out in the full range from pure mode I to pure mode II. The tests were conducted on two polyurethane materials characterized by different properties. The fracture parameters were obtained from experiments and are compared with the predictions based on the generalized MTS criterion (GMTS). The agreement between the experimental results and those predicted based on the GMTS criterion is discussed finally.

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