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SMA actuator based on gradient prestrain

A pre-strain, actuator technology, applied in the direction of machines/engines, mechanisms that generate mechanical power, mechanical equipment, etc., can solve problems such as interface failure, product failure, interface debonding, etc., to achieve extended service life and good driving performance. , the effect of prolonging the number of incentives

Active Publication Date: 2020-11-10
TONGJI UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to overcome the defect that the interface between the shape memory alloy and the substrate or the base material is prone to debonding and cause product failure in the above-mentioned prior art, and proposes a SMA actuator based on gradient prestrain, which effectively solves the previous problems. Intelligent composite structures based on uniformly prestrained shape memory alloy actuators are prone to interface failure bottlenecks

Method used

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  • SMA actuator based on gradient prestrain

Examples

Experimental program
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Effect test

Embodiment 1

[0039] An SMA actuator based on NITi shape memory alloy wire, which is prepared by introducing gradient pre-strain on NITi shape memory alloy wire, specifically embedding it inside the structure made of matrix material, when When heated in a certain way to increase the temperature above the SMA phase transition temperature, it will have a deformation tendency to return to the shape before the introduction of pre-strain, resulting in deformation of the composite structure and changes in stiffness.

[0040] In this embodiment, the shape memory alloy wire composite structure is as follows Figure 7 As shown, it includes the base body 1 and the SMA actuator buried in the base body 1, wherein the SMA actuator is divided into three parts, specifically two end sections 2, 3 and a middle section 4, the extension in the figure The SMA section 5 out of the matrix does not have actuation performance and is not a component of the SMA actuator. In the end sections 2 and 3, the prestrain i...

Embodiment 2

[0050] A SMA actuator based on NITi shape memory alloy wire, which is prepared by introducing gradient pre-strain on NITi shape memory alloy wire, specifically embedding it inside a structural member made of a certain material, When heated in a certain way to increase the temperature above the SMA phase transition temperature, it will have a deformation tendency to return to the shape before the introduction of pre-strain, resulting in deformation of the composite structure and changes in stiffness. In the entire length of the buried section, the gradient prestrain is introduced near the end region of the composite structure protruding from the SMA, while the middle section of the entire buried section can be a uniform prestrained section, and the prestrain is uniform from the end to the middle. The pre-strain of the strain section is increasing, and the increasing way can be stepped.

[0051] The shape memory alloy actuator of this embodiment is in the shape of wire, such as ...

Embodiment 3

[0054] A SMA actuator based on NITi shape memory alloy wire, which is prepared by introducing gradient pre-strain on NITi shape memory alloy wire, specifically embedding it inside a structural member made of a certain material, When heated in a certain way to increase the temperature above the SMA phase transition temperature, it will have a deformation tendency to return to the shape before the introduction of pre-strain, resulting in deformation of the composite structure and changes in stiffness. In the entire length of the buried section, the gradient prestrain is introduced near the end region of the composite structure protruding from the SMA, while the middle section of the entire buried section can be a uniform prestrained section, and the prestrain is uniform from the end to the middle. The pre-strain of the strain section is increasing, and the increasing way can be stepped.

[0055] The shape memory alloy actuator of this embodiment is filamentous, that is, its cros...

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Abstract

The invention relates to an SMA actuator based on gradient prestrain. The SMA actuator introduces prestrain in its entire length range, and the prestrain is distributed on two end sections and one middle section. The prestrain on the two end sections progressively increases in a gradient or continuous manner in the direction from the ends to the middle, the maximum value of the prestrain on the two end sections does not exceed the prestrain on the middle section, and the prestrain of the middle section is uniformly distributed. Compared with an existing SMA actuator based on uniform prestrain,the SMA actuator based on gradient prestrain has the advantages that concentration of the interface stress, at the end of a buried section or the end of a bonding section, of the actuator and a basematerial can be effectively controlled when the actuator is powered on or driven thermally in other modes, the service life of a composite structure can be remarkably prolonged, and the service performance of the composite structure can be remarkably improved.

Description

technical field [0001] The invention relates to the technical field of SMA actuators, and mainly relates to an SMA actuator based on gradient prestrain. Background technique [0002] It is well known that actuators can be fabricated by utilizing the shape memory effect of shape memory alloys by introducing pre-strain on them. When using a composite method to embed the SMA actuator in a material (it can be a single isotropic material or various types of composite materials, hereinafter collectively referred to as the matrix) or bonded to a solid material ( When the surface of the substrate (hereinafter referred to as the base material) is prepared into a certain structure or product, when it is heated in a certain way to exceed the phase transition temperature, it will drive the structure or product to produce corresponding deformation, etc., resulting in the structure and product Changes in shape, vibration characteristics, etc., but at the same time as it drives the struct...

Claims

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Application Information

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IPC IPC(8): F03G7/06
CPCF03G7/065
Inventor 袁国青朱同舟林再伟
Owner TONGJI UNIV
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