Large Strain in CuO‐added (Na 0.2 K 0.8 )NbO 3 Ceramic for Use in Piezoelectric Multilayer Actuators

2015 ◽  
Vol 99 (3) ◽  
pp. 938-945 ◽  
Author(s):  
Ji‐Hyun Lee ◽  
Dae‐Hyeon Kim ◽  
In‐Tae Seo ◽  
Jong‐Hyun Kim ◽  
Jong‐Seong Park ◽  
...  
Keyword(s):  
Large Strain ◽  
Multilayer Actuators

scholarly journals Thermally stable large strain in low‐loss (Na 0.2 K 0.8 )NbO 3 ‐BaZrO 3 for multilayer actuators

2019 ◽  
Vol 102 (11) ◽  
pp. 6837-6849 ◽  
Author(s):  
Sun‐Woo Kim ◽  
Tae‐Gon Lee ◽  
Dae‐Hyeon Kim ◽  
Eun‐Ji Kim ◽  
Dae Su Kim ◽  
...  
Keyword(s):  
Large Strain ◽  
Thermally Stable ◽  
Low Loss ◽  
Multilayer Actuators

(Na 1/2 Bi 1/2 )TiO 3 ‐based lead‐free co‐fired multilayer actuators with large strain and high fatigue resistance

2019 ◽  
Vol 102 (10) ◽  
pp. 6147-6155 ◽  
Author(s):  
Haibo Zhang ◽  
Weigang Ma ◽  
Bing Xie ◽  
Ling Zhang ◽  
Shuxiang Dong ◽  
...  
Keyword(s):  
Fatigue Resistance ◽  
Large Strain ◽  
Lead Free ◽  
High Fatigue ◽  
Multilayer Actuators

Small and large strain behaviour of an unsaturated compacted silt

2008 ◽  
Vol 12 (3) ◽  
pp. 203-228 ◽  
Author(s):  
Said Taïbi ◽  
Jean-Marie Fleureau ◽  
Sigit Hadiwardoyo ◽  
Siba Kheirbek-Saoud
Keyword(s):  
Large Strain ◽  
Strain Behaviour

Analytical Solutions for Circular Bars Subjected to Large Strain Plastic Torsion

1990 ◽  
Vol 57 (2) ◽  
pp. 298-306 ◽  
Author(s):  
K. W. Neale ◽  
S. C. Shrivastava
Keyword(s):  
Closed Form ◽  
Analytical Solutions ◽  
Large Strain ◽  
Kinematic Hardening ◽  
Flow Theory ◽  
Constitutive Laws ◽  
Isotropic Hardening ◽  
Large Strains ◽  
Inelastic Behavior ◽  
Rate Dependent

The inelastic behavior of solid circular bars twisted to arbitrarily large strains is considered. Various phenomenological constitutive laws currently employed to model finite strain inelastic behavior are shown to lead to closed-form analytical solutions for torsion. These include rate-independent elastic-plastic isotropic hardening J2 flow theory of plasticity, various kinematic hardening models of flow theory, and both hypoelastic and hyperelastic formulations of J2 deformation theory. Certain rate-dependent inelastic laws, including creep and strain-rate sensitivity models, also permit the development of closed-form solutions. The derivation of these solutions is presented as well as numerous applications to a wide variety of time-independent and rate-dependent plastic constitutive laws.

Microstructural Design of an AlMgSi Alloy via ECAP Processing: An Advanced SPD Manufacturing Technique for NC/UFG Materials

2015 ◽  
Vol 1114 ◽  
pp. 143-148
Author(s):  
Nicolae Serban ◽  
Doina Răducanu ◽  
Vasile Danut Cojocaru ◽  
Nicolae Ghiban
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Grain Refinement ◽  
Shape Change ◽  
Large Strain ◽  
Metallographic Analysis ◽  
Cross Sectional ◽  
Ecap Processing ◽  
Microstructural Design ◽  
Almgsi Alloy

Severe plastic deformation (SPD) has received enormous interest over the last two decades as a method capable of producing fully dense and bulk ultra-fine grained (UFG) and nanocrystalline (NC) materials. Significant grain refinement obtained by SPD leads to improvement of mechanical, microstructural and physical properties. Compared to classical deformation processes, the big advantage of SPD manufacturing techniques, represented in particular by equal channel angular pressing (ECAP) is the lack of shape-change deformation and the consequent possibility to impart extremely large strain. In ECAP processing, the workpiece is pressed through a die in which two channels of equal cross-section intersect at an angle of ϕ and an additional angle of ψ define the arc of curvature at the outer point of intersection of the two channels. As a result of pressing, the sample theoretically deforms by simple shear and retains the same cross-sectional area to allow repeated pressings for several cycles. A commercial AlMgSi alloy was investigated in our study. The specimens were processed at room temperature for multiple passes, using three different ECAP dies. All samples (ECAP processed and as-received) were subjected to metallographic analysis and mechanical testing. Several correlations between the main processing parameters and the resulting microstructural aspect and mechanical features for the processed material were established. It was shown that severe plastic deformation by means of ECAP processing can be used in aluminum alloys microstructural design as an advanced tool for grain refinement in order to attain the desired microstructure and mechanical properties.

scholarly journals Strain effects on polycrystalline germanium thin films

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Toshifumi Imajo ◽  
Takashi Suemasu ◽  
Kaoru Toko
Keyword(s):  
Thin Films ◽  
Solid Phase ◽  
Growth Promotion ◽  
Large Strain ◽  
Compressive Strain ◽  
Substrate Material ◽  
Large Crystal ◽  
Solid Phase Crystallization ◽  
Strain Effects ◽  
Thin Film Devices

AbstractPolycrystalline Ge thin films have attracted increasing attention because their hole mobilities exceed those of single-crystal Si wafers, while the process temperature is low. In this study, we investigate the strain effects on the crystal and electrical properties of polycrystalline Ge layers formed by solid-phase crystallization at 375 °C by modulating the substrate material. The strain of the Ge layers is in the range of approximately 0.5% (tensile) to -0.5% (compressive), which reflects both thermal expansion difference between Ge and substrate and phase transition of Ge from amorphous to crystalline. For both tensile and compressive strains, a large strain provides large crystal grains with sizes of approximately 10 μm owing to growth promotion. The potential barrier height of the grain boundary strongly depends on the strain and its direction. It is increased by tensile strain and decreased by compressive strain. These findings will be useful for the design of Ge-based thin-film devices on various materials for Internet-of-things technologies.

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