Photo-induced bending in a light-activated polymer laminated composite

Soft Matter ◽  
2015 ◽  
Vol 11 (13) ◽  
pp. 2673-2682 ◽  
Author(s):  
Xiaoming Mu ◽  
Nancy Sowan ◽  
Julia A. Tumbic ◽  
Christopher N. Bowman ◽  
Patrick T. Mather ◽  
...  
Keyword(s):  
Stress Relaxation ◽  
Intermediate Layer ◽  
Laminated Composite ◽  
Polymeric Composite ◽  
Free Standing

Photo-induced bending was achieved for a free-standing tri-layer polymeric composite by laminating a pre-stressed intermediate layer with light activated polymers and photo-triggered stress relaxation on one of the two side layers, allowing significant bending.

Activation Energy Measurement in Thin Gold Film by MEMS-Based Tensile Testing Device

Materials ◽  
2004 ◽  
Author(s):  
Jong H. Han ◽  
Taher M. Saif
Keyword(s):  
Activation Energy ◽  
Relaxation Time ◽  
Stress Relaxation ◽  
Analytical Model ◽  
Tensile Testing ◽  
Relaxation Times ◽  
Tensile Specimen ◽  
Testing Device ◽  
Free Standing ◽  
Tensile Tester

In this paper, we report a methodology to measure activation energy for time-dependent stress-relaxation in a thin free-standing tensile specimen by utilizing a MEMS-based tensile testing device. An analytical model is developed to investigate its stress-relaxation behavior. Along with this analytical model of the MEMS tensile tester, Arrhenius relation is applied to estimate relaxation times for different temperatures of a free-standing sample beam. From the relation between relaxation time and temperature, the activation energy for the stress-relaxation is obtained. For a 200-nm Au film, we obtained the relaxation time of 250, 67, and 40 seconds for the corresponding temperatures of 295, 312, and 323 K, respectively. The activation energy for stress-relaxation was 0.544 eV. The experimental data is fitted with the analytical model to find the relaxation time. The thin film on the MEMS tensile tester is prepared by sputter-deposition. By optical lithography and ICP DRIE Si etching, the MEMS tensile tester with a free standing beam is fabricated.

The influence of CdS intermediate layer on CdSe/CdS co-sensitized free-standing TiO2 nanotube solar cells

2018 ◽  
Vol 113 ◽  
pp. 696-705 ◽  
Author(s):  
Xuefeng Ren ◽  
Libo Yu ◽  
Zhen Li ◽  
Hai Song ◽  
Qingyun Wang
Keyword(s):  
Solar Cells ◽  
Intermediate Layer ◽  
Tio2 Nanotube ◽  
Free Standing

Properties of Composite Cylinders Fabricated by Bladder Assisted Composite Manufacturing

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
J. P. Anderson ◽  
M. C. Altan
Keyword(s):  
Fiber Volume Fraction ◽  
Volume Fraction ◽  
Laminated Composite ◽  
Polymeric Composite ◽  
Internal Heating ◽  
Fiber Volume ◽  
Composite Manufacturing ◽  
Manufacturing Method ◽  
Cure Temperature ◽  
Composite Cylinders

An innovative manufacturing method, bladder assisted composite manufacturing (BACM), to fabricate geometrically complex, hollow parts made of polymeric composite materials is presented. Unlike the conventional bladder or diaphragm assisted curing processes, BACM uses an internally heated bladder to provide the consolidation pressure at the required cure temperature. The feasibility of this manufacturing method is demonstrated by fabricating laminated composite cylinders using multiple cure pressures and number of plies. The elastic moduli, failure strength, fiber volume fraction, and void contents of the cylinders were found to be comparable to the values obtained from flat laminates produced by hot plate molding of the same material. Compared to conventional bladder manufacturing methods, the BACM process reduced the energy required to cure the cylinders by almost 50% due to internal heating and insulated mold.

scholarly journals Shear-stress relaxation in free-standing polymer films

2018 ◽  
Vol 98 (6) ◽  
Author(s):  
G. George ◽  
I. Kriuchevskyi ◽  
H. Meyer ◽  
J. Baschnagel ◽  
J. P. Wittmer
Keyword(s):  
Shear Stress ◽  
Stress Relaxation ◽  
Polymer Films ◽  
Free Standing ◽  
Shear Stress Relaxation

Stress relaxation in free-standing aluminum beams

2005 ◽  
Vol 476 (1) ◽  
pp. 118-124 ◽  
Author(s):  
Hoo-Jeong Lee ◽  
Ping Zhang ◽  
John C. Bravman
Keyword(s):  
Stress Relaxation ◽  
Free Standing

Monotonic Testing and Tension-Tension Fatigue Testing of Free-standing Al Microtensile Beams

2003 ◽  
Vol 795 ◽  
Author(s):  
Nicholas Barbosa ◽  
Paul El-Deiry ◽  
Richard P. Vinci
Keyword(s):  
Thin Films ◽  
Stress Relaxation ◽  
Strain Rate ◽  
Stress Level ◽  
Fatigue Testing ◽  
Monotonic Loading ◽  
Free Standing ◽  
Relaxation Dependence ◽  
Relaxation Experiments ◽  
Cycles To Failure

ABSTRACTFree-standing Al thin films were loaded statically and dynamically through the use of a custom-built microtensile system. The system is capable of performing monotonic loading/unloading up to 50 μm/s (10-1/s) and tension-tension fatigue experiments at 100 Hz on 600 μm long, 100 μm wide, and 1 μm thick free-standing Al microtensile beams. Monotonic loading/unloading and stress relaxation experiments have been performed. The microtensile beams show plasticity as well as a relaxation dependence on strain rate and stress level. Displacement controlled tension-tension fatigue experiments have also been performed. A trend of decreasing cycles to failure with increasing displacement amplitude and increasing mean displacement has been noted but requires further experimental exploration.

Stress Relaxation Study in 3C-SiC Microstructures by Micro-Raman Analysis and Finite Element Modeling

2013 ◽  
Vol 740-742 ◽  
pp. 673-676
Author(s):  
Nicolò Piluso ◽  
Ruggero Anzalone ◽  
Andrea Severino ◽  
Andrea Canino ◽  
Antonino La Magna ◽  
...  
Keyword(s):  
Finite Element ◽  
Stress Relaxation ◽  
Finite Element Modeling ◽  
Stress Tensor ◽  
Raman Mode ◽  
Mode Analysis ◽  
Free Standing ◽  
Element Modeling ◽  
Standing Structure ◽  
Si Films

In this paper, micro-Raman characterizations and Finite element modeling (FEM) of microstructures (cantilever, bridge, planar rotating probe) realized on single-crystal (100) 3C-SiC/Si films are performed. Transverse optical (TO) Raman mode analysis reveals the stress relaxation on the free standing structure (796.5 cm-1) respect to the stressed unreleased region (795.7 cm-1). The TO Raman mode exhibits an intense shift, up to 2 cm-1, located on the undercut region, where the Silicon substrate starts to be released. Such effect is ascribed to the modification of the Raman stress tensor that makes the generalized axial regime, described by diagonal components of the Raman stress tensor, unsuitable to describe the stress status on this region. Raman maps analysis and FEM simulations show the “activation” of the shear stress, i.e. non-diagonal components of the stress tensor. The aim of future works will be to minimize the stress field generation and the defects density within the epitaxial layer.

Stress relaxation and creep in free-standing thin Al films studied using a bulge tester

1999 ◽  
Author(s):  
A. J. Kalkman ◽  
A. H. Verbruggen ◽  
G. C. A. M. Janssen
Keyword(s):  
Stress Relaxation ◽  
Free Standing
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