Wyniki wyszukiwania - BazTech

1

Mechanical properties and advanced subjects in shape memory alloys and polymers

Matsui R., Takeda K., Tobushi H., Pieczyska E. A.

Journal of Theoretical and Applied Mechanics

|

2018

|

Vol. 56 nr 2

447--456

EN

Advanced subjects in mechanical properties of shape memory alloys and polymers are discussed. In the subloop loading under a stress-controlled condition of the shape memory alloy, the transformation-induced stress relaxation appears due to variation in temperature. The enhancement of corrosion and corrosion fatigue life of the shape memory alloy is discussed. The development of a functionally-graded shape memory alloy and polymer is expected to obtain better performance. Three-way motion appears in the shape memory composite with the shape memory alloy and polymer.

2

Torsional deformation properties of SMA tapes and their application to bias-type reciprocating rotary driving actuator

Takeda K., Matsui R., Tobushi H., Pieczyska E. A.

Archives of Mechanics

|

2017

|

Vol. 69, nr 4-5

289--303

EN

In order to develop the reciprocating rotary driving actuator with a simple mechanism using shape memory alloy (SMA) tapes, the graphical method to design the actuator was proposed based on the torsional deformation properties of SMA tapes. The torsional deformation properties of the SME tape showing the shape memory effect (SME) and the SE tape showing superelasticity (SE) were obtained. The bias-type reciprocating rotary actuator was composed of the pretwisted SME tape and the flat SE tape in series. The design chart expressed by the relationship between torque and twisting angle of the SME tape and the SE tape was proposed. The rotational angle and torque, which vary depending on temperature, can be estimated based on the design chart. The rotational angle is controlled by adjusting the mounting angle of the SME tape and the heating temperature. The automatically opening and closing blind driven by sunlight was demonstrated. The blind was controlled by using the reciprocating rotary element composed of the SME tape and the SE tape. The behavior of the blind can be achieved based on the proposed design method of the reciprocating rotary driving element.

3

Enhancement of bending fatigue life in TiNi shape-memory alloy tape by nitrogen ion implantation

Takeda K., Matsui R., Tobushi H., Homma S., Levintant-Zayonts N., Kucharski S.

Archives of Mechanics

|

2015

|

Vol. 67, nr 4

293--310

EN

A shape-memory alloy (SMA) is expected to be applied as intelligent or smart material since it shows the functional characteristics of the shape memory effect and superelasticity. Most SMA elements, with these characteristics, perform cyclic motions. In these cases, the fatigue property of SMA is one of the most important issues in view of evaluating functional characteristics of SMA elements. The fatigue properties are complex since they depend on stress, strain, temperature and their hysteresis. If an SMA is implanted with high-energy ions, the thermomechanical properties of the material may change, resulting in long fatigue life. In the present study, the nitrogen ion implantation was applied to modify the surface of a TiNi SMA tape and the influence of implantation treatment on the bending fatigue properties was investigated.

4

Creep and creep recovery under stress-controlled subloop loading in TiNi shape memory alloy

Takeda K., Matsui R., Tobushi H., Pieczyska E. A.

Archives of Mechanics

|

2013

|

Vol. 65, nr 5

429-444

EN

If a shape memory alloy (SMA) is subjected to the subloop loading under the stress-controlled condition, creep and creep recovery can appear based on the martensitic transformation. In the design of SMA elements, these deformation properties are important since the deflection of SMA elements can change under constant load. The conditions for the progress of the martensitic transformation are discussed based on the kinetics of the martensitic transformation for the SMA. The creep deformation properties are investigated experimentally for TiNi SMA. The creep strain rate increases in proportion to the martensitic transformation strain; the creep recovery strain rate increases in proportion to the reverse transformation strain.