Shape Memory Alloys in Civil Structures

Shape

 memory

 alloys

 in

 civil

 structures

  Abstract

With

 the

 development

 of

 materials

 and

 technology

 and

 deteriorating

 infrastructures,

 many

  new

 materials

 find

 their

 applications

 in

 civil

 engineering.

 Shape

 Memory

 Alloy

 (SMA)

 is

 a

  distinguished

 type

 of

 material

 that

 can

 adapt

 and

 convert

 thermal

 energy

 directly

 into

  mechanical

 work.

  From

 the

 early

 1930s,

 Shape

 memory

 effect

 (SME)

 for

 different

 alloys

 has

 been

  documented

 leading

 to

 multiple

 commercial

 products

 in

 the

 mechanical

 and

 aerospace

  industries.

 Nickel-­‐Titanium

 (Ni-­‐Ti)

 is

 the

 most

 commonly

 used

 SMA.

  With

 two

 crystal

 structures

 called

 Austenite

 and

 Martensite

 depending

 on

 temperature,

  SMA

 exhibits

 two

 special

 properties

 different

 from

 ordinary

 steels.

 One

 is

 shape

 memory,

  and

 the

 other

 is

 super-­‐elasticity.

 Both

 of

 these

 properties

 can

 suit

 varied

 applications

 in

  civil

 engineering,

 such

 as

 pre-­‐stress

 bars,

 self-­‐rehabilitation,

 isolation,

 energy

 dissipation,

  and

 two-­‐way

 actuators,

 etc.

  The

 objective

 of

 this

 paper

 is

 to

 explore

 the

 concept

 of

 smart

 material

 and

 explore

 the

  mechanical

 properties

 of

 SMA.

 The

 applications

 in

 civil

 structures

 will

 also

 be

 discussed,

  including

 strengthening,

 isolation

 and

 energy

 dissipation.

 Finally,

 a

 case

 study

 on

 a

  displacement

 control

 experiment...