Active Control of Chaotic Vibration in a Constrained Flexible Pipe Conveying Fluid

Yau, Chin‐Horng; Bajaj, Anil K.; Nwokah, O.D.I.

doi:10.1006/jfls.1995.1005

Cited by 36 publications

(18 citation statements)

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“…[3] Wi Pr interpolating function of tube deflection spatial derivatives of [Al cross sectional area of tube specific heat of fluid damping matrix of tube and tube element e Young's modulus of tube and tube element e convective heat transfer coefficient at inner and outer surfaces of tube heating current area moment of inertia of tube and tube element e thermal conductivity of tube stiffness matrix of tube and tube element e flexural stiffness matrix of tube element e geometric stiffness matrix of tube element e length of tube and tube element e mass of tube/unit tube length fluid mass flow rate mass of fluid/unit tube length mass matrix of tube and tube element e number of tube finite elements inner and outer perimeter of tube time tube, fluid and ambient temperatures transverse deflection of tube cartesian coordinate along tube axis the deflection vector of tube element natural frequency of the ith mode electrical resistivity of tube…”

Section: Discussionmentioning

confidence: 97%

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<title>Active stability control of shape memory tubes conveying fluids</title>

Baz

Chen

1994

SPIE Proceedings

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The instability of elastic tubes conveying fluids is controlled by manufacturing these tubes from a NIckel-TItanium alloy (NITINOL) which has unique shape memory characteristics. For example, the modulus of elasticity of the NITINOL tubes increases about threefold as the alloy undergoes its martensitic phase transformation. Deflection of the tube off the unbuckled shape, due to high internal flow velocities and elastic instabilities, triggers an active control system which activates the shape memory effect to increase the flexural rigidity of the tubes and bring them back to their original undeflected shape.A mathematical model is developed to describe the fundamentals governing the operation of this class of actively controlled NITINOL tubes while conveying fluids.The model describes the interaction between the fluid flow, the elastic behavior of the tubes and the thermal activation of the shape memory effect.The predictions of the model are validated experimentally using a 0.58 m long NITINOL-55 tube that has outer diameter of 2.134 mm and inner diameter of 1.778 mm. The effect of varying the activation strategy of the shape memory effect on the critical flow velocity, at which flow-induced instabilities occur, is determined theoretically and experimentally.It is shown that the shape memory controller can significantly increase these critical flow velocities as it stiffens the tubes by virtue of the strain energy imparted by the shape recovery process. Furthermore, the effectiveness of the controller is demonstrated also by its speed of response as it brings the unstable tubes back to their undeflected shape while conveying fluids at velocities equal to their uncontrolled critical velocities. Close agreement is obtained between the theoretical predictions and the experimental results.The results presented suggest the potential of the shape memory controller as a viable means for enhancing the elastic stability of tubes conveying fluids.

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Section: Discussionmentioning

confidence: 97%

“…where 13e1 and define the nodal deflection, velocity and acceleration vectors such that the nodal deflection vector is related to the transverse deflection w by: w = [Al e' (3) where the elements of the interpolating matrix [A] are function of x (Zienkiewicz and Taylor 1989)). …”

Section: Mathematicalmentioning

confidence: 99%

<title>Active stability control of shape memory tubes conveying fluids</title>

Baz

Chen

1994

SPIE Proceedings

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“…Furthermore, they clarified that the H controller was robust against the change in properties of the pipe system caused by increasing flow velocity, in comparison with a PID controller (Doki et al 1996). Recently, a study on the active control of chaotic vibration of a pipe was reported by Yau et al (1995).…”

Section: Introductionmentioning

confidence: 95%

Active Control of Cantilevered Pipes Conveying Fluid With Constraints on Input Energy

Doki

Hiramoto

Skelton³

1998

Journal of Fluids and Structures

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“…In particular, the problem of optimal design of pipes conveying fluid has been studied by Langthjem (1996), Tanaka et al (1993) and Borglund (1998). Examples of work on active control of the same mechanical system are Yau et al (1995) and Chen & Jendrzejczyk (1985).…”

Section: Introductionmentioning

confidence: 99%

Active Nozzle Control and Integrated Design Optimization of a Beam Subject to Fluid-Dynamic Forces

Borglund

1999

Journal of Fluids and Structures

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Active Control of Chaotic Vibration in a Constrained Flexible Pipe Conveying Fluid

Cited by 36 publications

References 0 publications

<title>Active stability control of shape memory tubes conveying fluids</title>

<title>Active stability control of shape memory tubes conveying fluids</title>

Active Control of Cantilevered Pipes Conveying Fluid With Constraints on Input Energy

Active Nozzle Control and Integrated Design Optimization of a Beam Subject to Fluid-Dynamic Forces

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