Quantitative nondestructive evaluation of delamination damage in CFRP pressure vessels for space use

2006 ◽  
Author(s):  
Takahide Sakagami ◽  
Shiro Kubo ◽  
Yukio Hyodo ◽  
Toshio Ogasawara ◽  
Takashi Nishimura ◽  
...  
Keyword(s):  
Nondestructive Evaluation ◽  
Space Use ◽  
Pressure Vessels ◽  
Delamination Damage

Identification of In-Plane Elastic Constants of Composite Laminates Using Measured Strains

1999 ◽  
Author(s):  
T. Y. Kam ◽  
C. H. Lin ◽  
W. T. Wang
Keyword(s):  
Nondestructive Evaluation ◽  
Minimization Problem ◽  
Composite Laminates ◽  
Global Minimum ◽  
Error Function ◽  
Laminated Composite ◽  
Pressure Vessels ◽  
Minimization Method ◽  
Material Constants ◽  
Constrained Minimization Problem

Abstract A method for nondestructive evaluation of material constants of composite laminates is presented. An error function is established to measure the differences between the theoretically and experimentally predicted strains. The identification of the material constants is formulated as a constrained minimization problem in which the material constants are determined to make the error function a global minimum. A global minimization method together with a technique for normalizing the gradient of the objective function are used to solve the above minimization problem. The applications of the proposed method are demonstrated by means of several examples on the material constants identification of laminated composite cylindrical pressure vessels.

Research and development roadmaps for nondestructive evaluation of cables, concrete, reactor pressure vessels, and piping fatigue

2013 ◽  
Author(s):  
Dwight A. Clayton ◽  
Sasan Bakhatiari ◽  
Cyrus Smith ◽  
Kevin Simmons ◽  
Pradeep Ramuhalli ◽  
...  
Keyword(s):  
Research And Development ◽  
Nondestructive Evaluation ◽  
Pressure Vessels ◽  
Reactor Pressure

Nondestructive Evaluation of FRP Design Criteria With Primary Consideration to Fatigue Loading

2004 ◽  
Vol 126 (2) ◽  
pp. 216-228 ◽  
Author(s):  
Guillermo Ramirez ◽  
Paul H. Ziehl ◽  
Timothy J. Fowler
Keyword(s):  
Nondestructive Evaluation ◽  
State Of The Art ◽  
Accurate Determination ◽  
Fatigue Loading ◽  
Pressure Vessels ◽  
Allowable Level ◽  
Strength Tests ◽  
Recorded Performances ◽  
Better Than

Design of FRP tanks and pressure vessels is based on criteria developed in the late 1960s using materials and procedures that represented the state of the art at the time. Maximum strain has been the controlling factor selected for the design of these vessels at an allowable level of 0.001. With the development of newer materials and systems with recorded performances of better than 0.001 this is now an inefficient limit in the design. Tests performed in the programs described in this paper indicate that newer materials perform well at higher strains. Results of strength tests performed here indicated that strains of 0.002 to 0.003 or better are possible in the safe design of tanks and pressure vessels. In addition, more accurate determination of design limits is possible if methods like acoustic emission are incorporated in the design process.

scholarly journals Probing for Flaws

2001 ◽  
Vol 123 (10) ◽  
pp. 73
Author(s):  
John DeGaspari
Keyword(s):  
Carbon Nanotubes ◽  
Nondestructive Evaluation ◽  
Evaluation Methods ◽  
Pressure Vessels ◽  
Scanning Probe ◽  
Haptic Interface ◽  
Research Center ◽  
High Altitudes ◽  
Langley Research Center ◽  
Fine Tune

This article focuses on NASA Langley that is manipulating carbon nanotubes to test for weaknesses in advanced aircraft materials. NASA’s Langley Research Center in Hampton, VA, is making use of nanotechnology to develop methods for nondestructive evaluation to support super lightweight, multifunctional structures. Carbon nanotubes, for instance, can be used as sensing elements embedded in materials. In general, nondestructive evaluation methods could be used to detect flaws in material structures, such as pressure vessels, air plane hulls that expand at high altitudes, or space stations subject to bombardment from meteorites. Using the NanoManipulator makes it possible to fine tune the position of the nanotubes. Besides plotting coordinates on a screen, the NanoManipulator’s haptic interface—a penlike device for guiding the scanning probe—will stop the user from pushing the probe tip through the surface of the sample.

Thickness Evaluation of Insulated Pipelines and Pressure Vessels Using Pulsed Eddy Current Technology

2012 ◽  
Author(s):  
Ehsan Shameli
Keyword(s):  
Nondestructive Evaluation ◽  
Eddy Current ◽  
Oil And Gas ◽  
Oil And Gas Industry ◽  
Pressure Vessels ◽  
Test Material ◽  
Gas Industry ◽  
Zero Crossing ◽  
Pulsed Eddy Current ◽  
Thickness Variations

Information about integrity of pipelines and pressure vessels is vital to the oil and gas industry. This emphasizes the need for fast and cost effective non-destructive testing solutions for monitoring and inspection of these components. However, due to reasons such as corrosion protection and temperature maintenance, pipelines and pressure vessels are usually coated throughout the oil and gas industry. These coatings also present a barrier to inspections and typically need to be removed prior to inspection with nondestructive evaluation (NDE) methods. This article presents a pulsed eddy current (PEC) system suitable for nondestructive evaluation of steel pipelines and pressure vessels without the need for removing the coating layers. A PEC probe was fabricated and a custom computer code with built in signal processing and data analysis functions was developed to collect the measurement signals and calculate thickness variations in the test objects. From a lift-off distance of 12mm, experiments were performed on eight SS304 stainless steel samples with thicknesses ranging from 1mm to 8mm. The SS304 steel was chosen as the test material to represent the steel type commonly used in the pipeline industry. A calibration curve based on the zero crossing time of initial measurements was obtained and implemented into the measurement software. Using the calibrated system, 25 measurements where performed on each sample. Statistical analysis of results showed that the proposed system can accurately detect thickness variations in the test samples with maximum measurement error of 3.3 percent.

Crack Formation and Propagation

MRS Bulletin ◽  
1989 ◽  
Vol 14 (8) ◽  
pp. 16-17 ◽  
Author(s):  
Otto Buck
Keyword(s):  
Nondestructive Evaluation ◽  
Air Force ◽  
Crack Formation ◽  
Pressure Vessels ◽  
Fracture Criteria ◽  
Quarter Century ◽  
Engineering Discipline ◽  
Fatigue And Fracture ◽  
Loaded Material ◽  
The U.S

After Griffith's explanation of the decrease in the strength of a loaded material containing a disbonded area (a crack), it took about another quarter century before “Fracture Mechanics” as an engineering discipline became established. At that time it was the catastrophic failure of the Liberty ships and the basic contributions by Irwin2 that created a high interest in the quantification of the process by which a crack will grow. A series of accidents involving bridges, pressure vessels, generator rotors, aircraft, etc., contributed greatly — not only to further research but also to the opinion that cracks are basically “bad” and should be avoided under all circumstances.I started to become acquainted with cracks in the early 1970s. The U.S. Air. Force had recently lost a few F-lll aircraft in southeast Asia due to wing-box cracking. In reaction, the Air Force decided that the new bomber, the B1, should be designed according to fatigue and fracture criteria. Since the materials were specified mostly by metallurgical engineers, they had to become concerned with the effects, for example, of the materials' microstructures on fatigue and crack propagation. At the same time, the interest in crack formation began to evolve.Furthermore, the capabilities for quantitative nondestructive evaluation of a structure in service increased sharply since it was realized that we have to live with cracks and that not all cracks are necessarily “bad.”

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