Influences of Specimen Size and Temperature on Viscoelastic Tensile Properties of SU-8 Photoresist Films

2016 ◽  
Vol 138 (2) ◽  
Author(s):  
Takahiro Namazu ◽  
Kenichi Takio ◽  
Shozo Inoue
Keyword(s):  
Stress Relaxation ◽  
Test Temperature ◽  
Fracture Strain ◽  
Thick Films ◽  
Tensile Tests ◽  
Specimen Size ◽  
Uniaxial Tensile ◽  
Apparent Thickness ◽  
The Mean ◽  
Apparent Activation Energies

In this paper, the influences of specimen size and test temperature on the viscoelastic properties of SU-8 photoresist films are described. Films with the thicknesses of 1 μm and 10 μm are subjected to quasi-static uniaxial tensile tests and stress relaxation tests at temperatures ranging from 293 K to 473 K. The average glassy modulus at 293 K is 3.2 GPa, which decreases with an increase in the test temperature irrespective of specimen size. The mean fracture strain depends on film thickness as well as temperature. The fracture strain of the 1-μm thick films is approximately half of that of the 10-μm thick films at each temperature. Stress relaxation tests are conducted for constructing the master curves of the relaxation moduli. There is no apparent thickness dependence on the master curve. Above glass transition temperature, Tg, apparent activation energies for the two films are almost identical, whereas the activation energy for the thinner films is smaller than that for the thicker films below Tg. This size effect is discussed using Fourier transform infrared spectroscopy (FTIR).

Influences of Specimen Size and Annealing Temperature on Mechanical Reliability of FIB-Fabricated Si Nanowires for NEMS

2013 ◽  
Author(s):  
Tatsuya Fujii ◽  
Koichi Sudoh ◽  
Shozo Inoue ◽  
Takahiro Namazu
Keyword(s):  
Young’S Modulus ◽  
Young's Modulus ◽  
Ion Beam ◽  
High Vacuum ◽  
Specimen Size ◽  
Film Deposition ◽  
Uniaxial Tensile ◽  
Si Nanowires ◽  
Uniaxial Tensile Testing ◽  
The Mean

This paper describes the effects of specimen size, focused ion beam (FIB) induced damage, and annealing on the mechanical properties of sub-100nm-sized silicon (Si) nanowires (NWs) that were evaluated by means of uniaxial tensile testing. Si NWs were made from silicon-on-nothing membranes that were produced by deep reactive ion etching trench fabrication and ultra-high vacuum (UHV) annealing. FIB system’s probe manipulation and film deposition functions were used to fabricate Si NWs and to directly bond them onto the sample stage of a tensile test device. The mean Young’s modulus and the mean strength of FIB-damaged NWs were 131.0 GPa and 5.6 GPa, respectively. After 700°C and 1000°C annealing in UHV, the mean Young’s modulus was increased to 168.1 GPa and 169.4 GPa, respectively, due to recrystallization by annealing. However, the mean strength was decreased to 4.1 GPa and 4.0 GPa, respectively. These experimental facts imply that the crystallinity of NWs improved, but the morphology was degraded. The surface degradation was probably related to gallium ion implantation into NWs surface during FIB fabrication.

scholarly journals Russet Susceptibility in Apple Is Associated with Skin Cells that Are Larger, More Variable in Size, and of Reduced Fracture Strain

Plants ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1118
Author(s):  
Bishnu P. Khanal ◽  
Thi Lieu Le ◽  
Yiru Si ◽  
Moritz Knoche
Keyword(s):  
Fruit Development ◽  
Fracture Strain ◽  
Indirect Evidence ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Growth Stages ◽  
Skin Cells ◽  
Surface Disorder ◽  
Apple Cultivars ◽  
Tangential Surface

Russeting is an economically important surface disorder in apple (Malus × domestica Borkh). Indirect evidence suggests an irregular skin structure may be the cause of the phenomenon. The objective of this study was to characterize epidermal and hypodermal cell morphology and the mechanical properties of the skins of apple cultivars of differing russet susceptibility. Dimensions of epidermal and hypodermal cells were determined using microscopy. Stiffness (S), maximum force (Fmax), and maximum strain (εmax) at failure were quantified using uniaxial tensile tests of skin strips. Particularly during early fruit development, epidermal cells (EC) and hypodermal cells (HC) in russet non-susceptible cultivars occurred in greater numbers per unit area than in russet-susceptible ones. The EC and HC were lower in height, shorter in length, and of reduced tangential surface area. There were little differences in S or Fmax between non-susceptible and susceptible cultivars. However, the εmax were higher for the skins of non-susceptible cultivars, than for those of susceptible ones. This difference was larger for the young than for the later growth stages. It is concluded that russet-susceptible cultivars generally have larger cells and a wider distribution of cell sizes for both EC and HC. These result in decreased εmax for the skin during early fruit development when russet susceptibility is high. This increases the chances of skin failures which is known to trigger russeting.

Effect of Prestrain on Tensile and Fracture Toughness Properties of Line Pipes

2002 ◽  
Author(s):  
Naoki Fukuda ◽  
Naoto Hagiwara ◽  
Tomoki Masuda
Keyword(s):  
Base Metal ◽  
Bauschinger Effect ◽  
Fracture Strain ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Crack Tip Opening Displacement ◽  
Opening Displacement ◽  
Line Pipe ◽  
Critical Fracture ◽  
Crack Tip Opening

To investigate the mechanical properties of pipeline subjected to plastic deformation, tensile tests and crack-tip-opening displacement (CTOD) tests were conducted on X60, X65 and X80 line pipe steels with uniaxial tensile or compressive prestrain, εpr. The tensile tests revealed that the Bauschinger effect and work hardening were dependent on the yield-to-tensile ratio (Y/T) of the steels; the change in yield stress due to prestrain linearly depended on the Y/T of the base metal. A critical CTOD for crack initiation decreased with increasing |εpr|.Compressive prestrain had a larger effect on the reduction of the critical CTOD than tensile prestrain. The reduction in the critical CTOD due to tensile prestrain was predictable with a simplified theoretical model employing a critical fracture strain of the base metal.

scholarly journals Experimental Analysis of Plantar Fascia Mechanical Properties in Subjects with Foot Pathologies

2021 ◽  
Vol 11 (4) ◽  
pp. 1517
Author(s):  
Silvia Todros ◽  
Carlo Biz ◽  
Pietro Ruggieri ◽  
Piero G. Pavan
Keyword(s):  
Mechanical Properties ◽  
Elastic Modulus ◽  
Stress Relaxation ◽  
Healthy Subjects ◽  
Human Subjects ◽  
Fibrous Tissue ◽  
Plantar Fascia ◽  
Tensile Tests ◽  
Uniaxial Tensile ◽  
Foot Biomechanics

Plantar Fascia (PF) is a fibrous tissue that plays a key role in supporting the foot arch; it can be affected by several pathologies that can alter foot biomechanics. The present study aims at investigating the mechanical behavior of PF and evaluating possible correlations between mechanical properties and specific pathologies, namely diabetes and plantar fibromatosis (Ledderhose syndrome). PF samples were obtained from 14 human subjects, including patients with Ledderhose syndrome, patients affected by diabetes and healthy subjects. Mechanical properties of PF tissues were evaluated on three samples from each subject, by cyclic uniaxial tensile tests up to 10% of maximum strain and stress relaxation tests for 300 s, in hydrated conditions at room temperature. In tensile tests, PF exhibits non-linear stress–strain behavior, with a higher elastic modulus (up to 25–30 MPa) in patients affected by Ledderhose syndrome and diabetes with respect to healthy subjects (elastic modulus 10 ÷ 14 MPa). Stress-relaxation tests show that PF of patients affected by Ledderhose syndrome and diabetes develop more intense viscous phenomena. The results presented in this work represent the first experimental data on the tensile mechanical propertied of PF in subjects with foot diseases and can provide an insight on foot biomechanics in pathological conditions.

EXPERIMENTAL VALIDATION OF A MEAN FILED MODEL OF MINERALIZED COLLAGEN FIBER ARRAYS AT TWO LEVELS OF HIERARCHY

2014 ◽  
Vol 14 (02) ◽  
pp. 1450013 ◽  
Author(s):  
EWA M. SPIESZ ◽  
ANDREAS G. REISINGER ◽  
PAUL ROSCHGER ◽  
PHILIPPE K. ZYSSET
Keyword(s):  
Mean Field ◽  
Tensile Tests ◽  
Field Method ◽  
Collagen Fibrils ◽  
Uniaxial Tensile ◽  
Mean Field Model ◽  
The Mean ◽  
Specific Tissue ◽  
Local Stiffness ◽  
Mineralized Collagen

In the course of this study, stiffness of a fibril array of mineralized collagen fibrils modeled with a mean field method was validated experimentally at site-matched two levels of tissue hierarchy using mineralized turkey leg tendons (MTLT). The applied modeling approaches allowed to model the properties of this unidirectional tissue from nanoscale (mineralized collagen fibrils) to macroscale (mineralized tendon). At the microlevel, the indentation moduli obtained with a mean field homogenization scheme were compared to the experimental ones obtained with microindentation. At the macrolevel, the macroscopic stiffness predicted with micro finite element (μFE) models was compared to the experimental stiffness measured with uniaxial tensile tests. Elastic properties of the elements in μFE models were injected from the mean field model or two-directional microindentations. Quantitatively, the indentation moduli can be properly predicted with the mean-field models. Local stiffness trends within specific tissue morphologies are very weak, suggesting additional factors responsible for the stiffness variations. At macrolevel, the μFE models underestimate the macroscopic stiffness, as compared to tensile tests, but the correlations are strong.

scholarly journals Tensile Behavior of Low Density Thermally Bonded Nonwoven Material

2009 ◽  
Vol 4 (1) ◽  
pp. 155892500900400 ◽  
Author(s):  
Xiaonan Hou ◽  
Memiş Acar ◽  
Vadim V. Silberschmidt
Keyword(s):  
Tensile Loading ◽  
Nonwoven Material ◽  
Tensile Tests ◽  
Specimen Size ◽  
Tensile Behavior ◽  
Uniaxial Tensile ◽  
Low Density ◽  
Uniform Microstructure ◽  
Deformational Behavior ◽  
And Performance

A discontinuous and non-uniform microstructure of a low-density thermally bonded nonwoven material displays in a complicated and unstable tensile behavior. This paper reports uniaxial tensile tests of a low density thermally bonded nonwoven to investigate the effect of the specimen size and shape factor, as well as the cyclic tensile loading conditions employed to investigate the deformational behavior and performance of the nonwoven at different loading stages. The experimental data are compared with results of microscopic image analysis and FE models.

Quasi-Static and Fatigue Fracture Strength of Microsized Silicon Film Measured by On-Chip Test Method

2000 ◽  
Author(s):  
Taeko Ando ◽  
Tetsuo Yoshioka ◽  
Mitsuhiro Shikida ◽  
Kazuo Sato
Keyword(s):  
Fracture Strain ◽  
Silicon Film ◽  
Single Crystal Silicon ◽  
Tensile Tests ◽  
Fatigue Tests ◽  
Test Method ◽  
Uniaxial Tensile ◽  
Silicon Thin Film ◽  
Crystal Silicon ◽  
On Chip

Abstract Quasi-static and fatigue tests under uniaxial tensile loading condition were carried out for single-crystal-silicon in a direction of <110> by using on-chip testing method. A film specimen and tensile testing system were integrated on a silicon chip. A measurement system allowing both quasi-static and dynamic loading was newly introduced. In quasi-static loading measured fracture strain of silicon thin-film was 3.4%. Fatigue fractures were observed during 103∼106 cycles when the maximum strains of sinusoidal wave were higher than the average fracture strain of tensile tests.

Mechanical Behavior of 980MPa NANOHITENTM at Elevated Temperatures and its Effect on Springback in Warm Forming

2014 ◽  
Vol 611-612 ◽  
pp. 11-18 ◽  
Author(s):  
Toru Minote ◽  
Yoshimasa Funakawa ◽  
Naoko Saito ◽  
Mitsugi Fukahori ◽  
Hiroshi Hamasaki ◽  
...  
Keyword(s):  
Tensile Strength ◽  
Stress Relaxation ◽  
Mechanical Behavior ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Tensile Tests ◽  
Warm Forming ◽  
Bending Test ◽  
Uniaxial Tensile ◽  
High Tensile Strength

High tensile strength steel sheets have large springback after being formend at room temperature. Warm forming can be a solution to reduce springback of high tensile strength steel parts. NANOHITENTM is a high strength ferritic steel precipitation-strengthened by nanometer-sized carbides developed by JFE Steel Corporation. Tensile strength of the steel at room temperature does not change before and after deformation at elevated temperatures up to 873K since the carbides in the steel are stable at high temperatures less than 973K. Therefore, the steel is suitable for warm forming. Springback of 980MPa NANOHITENTM parts warm formed at 873K is the same level of that of cold formed conventional 590MPa steel parts. In this study, two kinds of material testing at room temperature and at elevated temperatures between 573K and 937K were performed to understand the mechanical behavior of 980MPa NANOHITENTM: uniaxial tensile tests and bending tests. The steels flow stress depends on not only material temperature but also strain rate in uniaxial tensile tests. After a bending test, the specimen shows springback measured by the change of an angle between the two sides. Stress relaxation happens while a test specimen is held at the bottom dead point after bending. And the stress relaxation could be used to reduce springback of warm formed parts.

scholarly journals Texture Selection Mechanisms during Recrystallization and Grain Growth of a Magnesium-Erbium-Zinc Alloy

Metals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 171
Author(s):  
Fatim-Zahra Mouhib ◽  
Fengyang Sheng ◽  
Ramandeep Mandia ◽  
Risheng Pei ◽  
Sandra Korte-Kerzel ◽  
...  
Keyword(s):  
Grain Growth ◽  
Ternary Alloy ◽  
Solute Drag ◽  
Tensile Tests ◽  
Electron Back Scatter Diffraction ◽  
Zinc Alloy ◽  
Uniaxial Tensile ◽  
Microstructural Stability ◽  
Solid Solution Strengthening ◽  
Zener Drag

Binary and ternary Mg-1%Er/Mg-1%Er-1%Zn alloys were rolled and subsequently subjected to various heat treatments to study texture selection during recrystallization and following grain growth. The results revealed favorable texture alterations in both alloys and the formation of a unique ±40° transvers direction (TD) recrystallization texture in the ternary alloy. While the binary alloy underwent a continuous alteration of its texture and grain size throughout recrystallization and grain growth, the ternary alloy showed a rapid rolling (RD) to transvers direction (TD) texture transition occurring during early stages of recrystallization. Targeted electron back scatter diffraction (EBSD) analysis of the recrystallized fraction unraveled a selective growth behavior of recrystallization nuclei with TD tilted orientations that is likely attributed to solute drag effect on the mobility of specific grain boundaries. Mg-1%Er-1%Zn additionally exhibited a stunning microstructural stability during grain growth annealing. This was attributed to a fine dispersion of dense nanosized particles in the matrix that impeded grain growth by Zener drag. The mechanical properties of both alloys were determined by uniaxial tensile tests combined with EBSD assisted slip trace analysis at 5% tensile strain to investigate non-basal slip behavior. Owing to synergic alloying effects on solid solution strengthening and slip activation, as well as precipitation hardening, the ternary Mg-1%Er-1%Zn alloy demonstrated a remarkable enhancement in the yield strength, strain hardening capability, and failure ductility, compared with the Mg-1%Er alloy.

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