Low-cost design and fabrication of composite ship structures

1994 ◽  
Vol 7 (2-5) ◽  
pp. 475-494 ◽  
Author(s):  
Milton O. Critchfield ◽  
Thomas D. Judy ◽  
Alan D. Kurzweil
1997 ◽  
Author(s):  
Loc Nguyen ◽  
Thomas Juska ◽  
J. Mayes ◽  
Loc Nguyen ◽  
Thomas Juska ◽  
...  

2021 ◽  
Vol 9 (4) ◽  
pp. 379
Author(s):  
Sang-Gyu Lee ◽  
Daekyun Oh ◽  
Jong Hun Woo

Ship structures made of glass fiber-reinforced polymer (GFRP) composite laminates are considerably thicker than aircraft and automobile structures and more likely to contain voids. The production characteristics of such composite laminates were investigated in this study by ultrasonic nondestructive evaluation (NDE). The laminate samples were produced from E-glass chopped strand mat (CSM) and woven roving (WR) fabrics with different glass fiber contents of 30–70%. Approximately 300 pulse-echo ultrasonic A-scans were performed on each sample. The laminate samples produced from only CSM tended to contain more voids compared with those produced from a combination of CSM and WR, resulting in the relative density of the former being lower than the design value, particularly for high glass fiber contents of ≥50%. The velocity of the ultrasonic waves through the CSM-only laminates was also lower for higher glass fiber contents, whereas it steadily increased for combined CSM–WR laminates. Burn-off tests of the laminates further revealed that the fabric configuration of the combined CSM–WR laminates was of higher quality, prevented the formation of voids, and improved inter-layer bonding. These findings indicate that combined CSM–WR laminates should be used to achieve more accurate ultrasonic NDE of GFRP composite structures.


2005 ◽  
Author(s):  
Pradeep K. Sensharma ◽  
Malcolm Willis ◽  
Aaron Dinovitzer ◽  
Nat Nappi

The use of doubler plates or ‘doublers’ has become routine for temporary ship repairs. It is the preferred method for ships’ structural repairs for plate corrosion due to its relative ease and low cost of installation over the more costly permanent welded plate insert repair. A lack of performance data and engineering design guidance are the reasons that repairs with doublers are currently considered only temporary. This objective of this study was to develop a set of guidelines for designing and applying doubler plate repairs to ship structures. The guidelines were established using the following criteria: various stress analyses, buckling strength, corrosion types and rates, weld types, and doubler plate fatigue and fracture assessment. Studying and understanding doubler plate repair performance by comparison to that of the primary hull performance allows critical operational decisions to be made with greater ease and confidence. However, the ultimate goal of this study was to establish the design and limitations on the applications of doubler plate repairs for surface ships.


2020 ◽  
Vol 57 (2) ◽  
pp. 104-113
Author(s):  
Daekyun Oh ◽  
Zhiqiang Han ◽  
Jackyou Noh ◽  
Sookhyun Jeong

Author(s):  
Xiaowen Li ◽  
Zhaoyi Zhu ◽  
Yan Li ◽  
Qinglin Chen ◽  
Xiaoying Zhang

2006 ◽  
Vol 22 (04) ◽  
pp. 219-238
Author(s):  
Pradeep K. Sensharma ◽  
Malcolm Willis ◽  
Aaron Dinovitzer ◽  
Nat Nappi

The use of doubler plates or "doublers" has become routine for temporary ship repairs. It is the preferred method for ship structural repairs for plate corrosion due to its relative ease and low cost of installation over the more costly permanent welded plate insert repair. A lack of performance data and engineering design guidance are the reasons that repairs with doublers are currently considered only temporary. The objective of this study was to develop a set of guidelines for designing and applying doubler plate repairs to ship structures. The guidelines were established using the following criteria: various stress analyses, buckling strength, corrosion types and rates, weld types, and doubler plate fatigue and fracture assessment. Studying and understanding doubler plate repair performance by comparison to welded plate insert repair performance in the primary hull allows critical operational decisions to be made with greater ease and confidence. However, the ultimate goal of this study was to establish the design and limitations on the applications of doubler plate repairs for surface ships.


Author(s):  
Y. L. Chen ◽  
S. Fujlshiro

Metastable beta titanium alloys have been known to have numerous advantages such as cold formability, high strength, good fracture resistance, deep hardenability, and cost effectiveness. Very high strength is obtainable by precipitation of the hexagonal alpha phase in a bcc beta matrix in these alloys. Precipitation hardening in the metastable beta alloys may also result from the formation of transition phases such as omega phase. Ti-15-3 (Ti-15V- 3Cr-3Al-3Sn) has been developed recently by TIMET and USAF for low cost sheet metal applications. The purpose of the present study was to examine the aging characteristics in this alloy.The composition of the as-received material is: 14.7 V, 3.14 Cr, 3.05 Al, 2.26 Sn, and 0.145 Fe. The beta transus temperature as determined by optical metallographic method was about 770°C. Specimen coupons were prepared from a mill-annealed 1.2 mm thick sheet, and solution treated at 827°C for 2 hr in argon, then water quenched. Aging was also done in argon at temperatures ranging from 316 to 616°C for various times.


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