Reduction of Overwelding and Distortion for Naval Surface Combatants, Part 1: Optimized Weld Sizing for Lightweight Ship Structures

2014 ◽  
Vol 30 (04) ◽  
pp. 184-193
Author(s):  
T. D. Huang ◽  
Michael Harbison ◽  
Lee Kvidahl ◽  
David Niolet ◽  
John Walks ◽  
...  
Keyword(s):  
High Strength ◽  
Ship Design ◽  
Rate Of Change ◽  
Construction Costs ◽  
Plate Structures ◽  
Shipbuilding Industry ◽  
Average Production ◽  
Thin Steel ◽  
Two Factors ◽  
Designed Experiment

As high-strength thin-steel use in ship design increases, dimensional management becomes critical to control construction costs and schedule in ship production. In the U.S. shipbuilding industry, improvements to shipbuilding facilities and processing technology have not kept pace with the rate of change in ship design. Additionally, new designs using thinner steels are subject to legacy weld-sizing criteria, which may inappropriately size welds on lightweight materials. These two factors result in widespread overwelding, causing severe plate buckling in naval vessels during construction. The problem of overwelding has two distinct sources:the weld-sizing methods developed in the 1980s are still used in most shipbuilding specifications regardless of ship class. This prevents the incentive of application of latest technologies that can make strong, precision fillet welds for modern lightweight thin steel naval surface combatants; andshipyard welders tend to make welds even larger than design requirements to satisfy naval production specifications, which do not allow for any undersized welds. On average, production welds are 3 mm larger than design, which can more than double the heat input and distortion caused by welding. The approach to the solution of this overwelding problem will be described in detail in this article:develop appropriate weld-sizing criteria for thin plate structures; this can be facilitated by numerical modeling to ensure adequate static shear, tensile, bending, fatigue, and dynamic impact capacity of structural welds; andperform a robust designed experiment to establish confidence that small weld sizes can provide necessary performance and strength to meet the design service life of the vessel and provide data to NAVSEA technical warrant holders to support the implementation of an underweld tolerance for ship production to prevent overwelding.

Reduction of Overwelding and Distortion for Naval Surface Combatants, Part 2: Weld Sizing Effects on Shear and Fatigue Performance

2013 ◽  
Author(s):  
T. D. Huang ◽  
M. Harbison ◽  
L. Kvidahl ◽  
D. Niolet ◽  
J. Walks ◽  
...  
Keyword(s):  
Value Added ◽  
High Strength ◽  
Rate Of Change ◽  
Steel Plates ◽  
Construction Costs ◽  
Shipbuilding Industry ◽  
Plate Deformation ◽  
Surface Vessels ◽  
Two Factors ◽  
Dimensional Management

As high-strength thinner-steel implementation in ship designs increase, dimensional management becomes critical to control construction costs and schedule in ship production. In the US shipbuilding industry, improvements to shipbuilding facilities and processing technology have not kept pace with the rate of change in ship design. Additionally, new designs using thinner steels are subject to legacy weld sizing criteria possibly leading to inappropriately sized welds on lightweight materials. These two factors result in widespread overwelding; causing severe plate deformation in naval vessels during construction and non-value added labor to correct as needed for fit up tolerances. Historically, shear and fatigue strength data has been focused on the larger welds and thicker steel plates typical of the state of the practice when these legacy weld sizing criteria were developed. In order to optimize weld design and production in modern, lightweight naval surface vessels, there is a need to develop more accurate data about the performance of precision fillet welds for thin steels.

Reduction of Overwelding and Distortion for Naval Surface Combatants. Part 2: Weld Sizing Effects on Shear and Fatigue Performance

2016 ◽  
Vol 32 (01) ◽  
pp. 21-36
Author(s):  
T. D. Huang ◽  
Michael Harbison ◽  
Lee Kvidahl ◽  
David Niolet ◽  
John Walks ◽  
...  
Keyword(s):  
High Strength ◽  
Rate Of Change ◽  
Steel Plates ◽  
Construction Costs ◽  
Shipbuilding Industry ◽  
Plate Deformation ◽  
Surface Vessels ◽  
Two Factors ◽  
Dimensional Management ◽  
The U.S

As high-strength thinner-steel implementation in ship designs increase, dimensional management becomes critical to control construction costs and schedule in ship production. In the U.S. shipbuilding industry, improvements to shipbuilding facilities and processing technology have not kept pace with the rate of change in ship design. Additionally, new designs using thinner steels are subject to legacy weld sizing criteria possibly leading to inappropriately sized welds on lightweight materials. These two factors result in widespread overwelding, causing severe plate deformation in naval vessels during construction and nonvalue added labor to correct as needed for fit-up tolerances. Historically, shear and fatigue strength data has been focused on the larger welds and thicker steel plates typical of the state of the practice when these legacy weld sizing criteria were developed. In order to optimize weld design and production in modern, lightweight naval surface vessels, there is a need to develop more accurate data about the performance of precision fillet welds for thin steels.

Overwelding and distortion control for naval surface combatants

2012 ◽  
Author(s):  
T. D. Huang ◽  
M. Harbison ◽  
L. Kvidahl ◽  
D. Niolet ◽  
J. Walks ◽  
...  
Keyword(s):  
Thin Plate ◽  
Early Stage ◽  
Steel Structures ◽  
Ship Design ◽  
Rate Of Change ◽  
Fillet Welds ◽  
Naval Research ◽  
Process Technology ◽  
Thin Steel ◽  
Dimensional Management

As high-strength thin-steel usage in ship design increases, dimensional management becomes very critical to control rework costs and schedule delays in ship production. Prior Office of Naval Research (ONR) and National Shipbuilding Research Program (NSRP) projects have helped Ingalls Shipbuilding to emphasize dimensional control for thin steel structures. Huntington-Ingalls (previous Northrop Grumman Shipbuilding) has, in recent years, substantially increased its emphasis on dimensional management as an enabler to achieving its aggressive goals for the future. These goals include cost and lead time reduction for hull erection and increasing early-stage outfitting. Nevertheless, improvements to shipbuilding facilities and process technology have not kept pace with the rate of change in ship design. Worse, new designs using thinner steels are subject to legacy weld size requirements. These two factors result in widespread overwelding. Severe plate buckling in naval vessels has been attributed to oversized welds in thin plate ship structures. The problem of overwelding has two distinct sources: - The weld sizing method developed in the 1980s is still used in most shipbuilding specifications regardless of ship class. This prevents the incentive of application of latest technologies that can make strong, precision fillet welds for modern lightweight thin steel naval surface combatants. - Shipyard welders tend to make welds even larger than design requirement in order to satisfy Quality Assurance (QA) inspection. In a number of investigations, fillet welds requiring a leg size of 5mm are typically found to have an average size of 8mm, resulting in more than double the heat input and distortion. The approach to the solution of this overwelding problem will be described in detail in this paper: - Develop appropriate weld sizing criteria for thin plate structures-this can be facilitated by numerical modeling to ensure adequate static shear, tensile, bending, fatigue and dynamic impact capacity of structural welds; - Perform a robust designed experiment to confirm the models and establish confidence that precision weld sizes can provide necessary performance and strength throughout the design service life of the vessel.

Exploitation Load Impact on Electrochemical Properties of Shipbuilding 7xxx Series Aluminum Alloy Joints Prepared with TIG and FSW Methods

2015 ◽  
Vol 236 ◽  
pp. 53-61
Author(s):  
Wojciech Jurczak
Keyword(s):  
Mechanical Properties ◽  
Corrosion Potential ◽  
Tensile Load ◽  
Electrochemical Corrosion ◽  
High Strength ◽  
Shipbuilding Industry ◽  
Friction Stir ◽  
Superior Mechanical Properties ◽  
Series Aluminum Alloy ◽  
Joint Quality

The paper presents the results of investigations on mechanical properties and electrochemical potential distribution within arc welded (TIG) and friction stir welded (FSW) joints subjected to slow strain rate tests. The materials investigated were high-strength 7xxx series (7020 and its modification 7020M) aluminum alloys intended for shipbuilding. The objectives were joint quality assessment and comparison of the advantages of new FSW method with the traditional TIG methods commonly utilized in shipbuilding industry. Joint quality was evaluated based on mechanical investigations, hardness distribution tests and simultaneous electrochemical corrosion potential measurements at various locations within the welded joints.Initiation of corrosion processes on TIG and FSW joints was identified as a radical decrease in corrosion potential related to load followed by oxide layer cracking. Arc welded (TIG) joints of 7xxx series alloys undergo corrosion at lower values of tensile load applied as compared to the FSW joints. Superior mechanical properties and higher corrosion resistance of the FSW joints make this technology well-suited for joining high-strength 7xxx series alloys.

Integrated Multiple Attributive Decision Support System for Producibility Evaluation in Ship Design

2004 ◽  
Vol 20 (03) ◽  
pp. 147-163
Author(s):  
Osman Turan ◽  
Selim Alkaner ◽  
Aykut i. Ölçer
Keyword(s):  
Decision Support ◽  
Decision Support System ◽  
Support System ◽  
Ad Hoc ◽  
Labor Cost ◽  
Ship Design ◽  
Design Stage ◽  
Design Development ◽  
Shipbuilding Industry ◽  
Design For X

Ship design today can be viewed as an ad hoc process. It must be considered in the context of integration with other design development activities, such as production, costing, quality control, and so forth. Otherwise, it is possible for the designer to design a ship that is difficult to produce, requires high material or labor cost, or contains some design flaws that the production engineers have to correct or send back for redesigning before production can be done. Any adjustment required after the design stage will result in a penalty of extra time or cost. Deficiencies in the design of a ship will influence the succeeding stages of production. In addition to designing a ship that fulfills producibility requirements, it is also desirable to design a ship that satisfies risk, performance, cost, and customer requirements criteria. More recently, environmental concerns, safety, passenger comfort, and life-cycle issues are becoming essential parts of the current shipbuilding industry. Therefore, "design for X paradigm" should also be considered during the ship design stages. An integrated multiple attributive decision support system for producibility evaluation in ship design (PRODEVIS) is developed to use by industry and researchers in evaluating the producibility of competing ship designs and design features during the early stages of ship design by taking into account cost, performance, risk, and "design for X paradigm" attributes. This developed approach is a fuzzy multiple attributive group decision-making methodology where feasible design alternatives are conducted by a ship production simulation technique. In this approach, an attribute-based aggregation technique for a heterogeneous group of experts is employed and used for dealing with fuzzy opinion aggregation for the subjective attributes of the ship design evaluation problem. The developed methodology is illustrated with a case study.

scholarly journals EXPERIENCE IN THE DEVELOPMENT AND USE OF ALUMINUM ALLOY CASING FOR CONDITIONS OF HIGH CONTENT OF ACID GASES IN FORMATION FLUIDS

2019 ◽  
Vol 121 ◽  
pp. 04013
Author(s):  
Vladimir Sledkov ◽  
Mikhail Gelfgat ◽  
Dmitry Basovich
Keyword(s):  
Aluminum Alloy ◽  
Aluminium Alloy ◽  
Weight Ratio ◽  
High Strength ◽  
Acid Gases ◽  
Construction Costs ◽  
Corrosion Resistant

When selecting a casing material for fields with a high content of H2S and CO2, it is recommended to use specialized corrosion-resistant tubulars with high content of chrome of the Sanicro 29 type. The high cost of the material can be critical for the project economy. A promising approach for these problems elimination could be the application of aluminium alloy casing pipes. They are remain inert to corrosion even if the formation environment is fully saturated with H2S and/or CO2. They are also lightweight, have high strength-to-weight ratio, and thus decrease the existing tensions in the string and reduce well construction costs.

Beam-column behaviour of steel tubes filled with high strength concrete

1994 ◽  
Vol 21 (2) ◽  
pp. 207-218 ◽  
Author(s):  
Helmut G. L. Prion ◽  
Jens Boehme
Keyword(s):  
Cyclic Loading ◽  
High Strength Concrete ◽  
High Strength ◽  
Test Results ◽  
Loading Test ◽  
Steel Tubes ◽  
Strength Concrete ◽  
Main Emphasis ◽  
Thin Steel ◽  
Current Code

The results of an investigation into the behaviour of thin-walled steel tubes filled with high strength concrete are presented. The main emphasis is placed on the level of ductility that can be achieved, considering the fact that neither high strength concrete nor thin steel tubes are individually able to absorb significant amounts of energy under cyclic loading. Results of 26 tests on specimens with a diameter of 152 mm and a wall thickness of 1.7 mm, filled with concrete of characteristic compressive strength ranging between 73 and 92 MPa, are reported. Load combinations on the specimens range from pure axial compression, through various combinations of axial load and bending, to pure bending. Three specimens were subjected to cyclic loading. Test results are compared with design models that are used in current code specifications. Key words: steel tubes, concrete, composite, beam-column, beam, column, experimental.

scholarly journals Expulsion investigation and fracture characteristics in spot welded advanced high strength auto steels

2021 ◽  
Author(s):  
Chao Ma
Keyword(s):  
Control Strategies ◽  
Fatigue Crack Initiation ◽  
High Strength Steels ◽  
High Strength ◽  
Fatigue Tests ◽  
Rate Of Change ◽  
Dynamic Resistance ◽  
Monitoring And Control ◽  
Advanced High Strength Steels ◽  
Electrode Force

Increased use of advanced high strength steels in resistance spot welding (RSW) is necessary for manufacturing safe and affordable vehicles. Unfortunately, the investigation of expulsion monitoring and control of advanced high strength steels (AHSS) is limited. A data acquisition system was designed for monitoring weld expulsion via the measurement of voltage, current, dynamic resistance, electrode force and displacement. Three control strategies were proposed on the basis of the rate of change in the dynamic resistance, the electrode force and the electrode displacement. Micro-hardness tests, tensile shear tests and fatigue tests were carried out. The expulsion effects on the mechanical properties, fracture modes, and metallurgical features were investigated using optical microscopy, scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Fatigue crack initiation locations were also observed, which were verified by the theorectical stress analysis. In addition, the causes of interfacial fracture were discussed in relation to weld parameters.

scholarly journals Responses of Upland Rice cv Inpago LIPI Go4 to Microbial Inoculant and Nitrogen Fertilization Dosage Treatments

2020 ◽  
Vol 12 (11) ◽  
pp. 78
Author(s):  
Reni Lestari ◽  
Kartika Ning Tyas ◽  
Arief Noor Rachmadiyanto ◽  
Didi Usmadi ◽  
Mahatma Gandhi ◽  
...  
Keyword(s):  
Plant Height ◽  
Upland Rice ◽  
Trichoderma Viride ◽  
Tiller Number ◽  
Rice Production ◽  
N Fertilizer ◽  
Dry Land ◽  
Microbial Inoculant ◽  
Average Production ◽  
Two Factors

There is a huge potential of upland for developing food crops to shortage the increase in rice production in Indonesia. Upland rice that adaptable to dry land could support national rice production. Among the limit factors of upland rice productivity in Indonesia are infertile land and cultivation practices. The purpose of the study was to find out the effect of microbial inoculant application combined with nitrogen (N) fertilizer dosage to the cultivation of upland rice Inpago LIPI Go4. The factorial experimental design with two factors was applied, namely the supply of microbial inoculant and the dosage of N fertilizer and, i.e., 0%, 50%, 100% N (200 kg ha-1 Urea). The inoculant comprises of Aspergillus niger, Trichoderma viride, and Azotobacter. Each treatment combination was repeated four times. The microbial inoculant treatment solely effects significantly plant height, tiller number, and panicle weight of the upland rice, whereas N dosage treatment solely influences significantly plant height and tiller number. There was no interaction significant effect of microbial inoculant and N fertilizer dosage to all growth, production, and content of leaf N parameters. The maximum production of the upland rice was 4499 kg ha-1, whereas the average production was 3816 kg ha-1 grain weight. The highest yield was obtained from the plant with the supply of microbial inoculant and the treatment of 50% N fertilizer (100 kg ha-1 Urea).

scholarly journals The Lightship Mass Calculation Model Of A Merchant Ship By Empirical Methods

2021 ◽  
Vol 93 (6s) ◽  
pp. 73-87
Author(s):  
Vedran Slapničar ◽  
◽  
Katarina Zadro ◽  
Viktor Ložar ◽  
Ivo Ćatipović ◽  
...  
Keyword(s):  
Least Squares Method ◽  
Early Stage ◽  
Calculation Model ◽  
Ship Design ◽  
Empirical Methods ◽  
Construction Costs ◽  
Hull Steel ◽  
The One ◽  
The Masses ◽  
Preliminary Phase

Estimating the lightship mass is an important factor in the early stage of ship design given its impact on shipbuilding costs. The mass of the hull and equipment, as well as its distribution, affects the hull strength, deadweight, and stability of the ship. Furthermore, a good estimate of the lightship mass in the preliminary phase is very important for defining the construction costs as accurately as possible. As the time available to the designer in the conceptual or preliminary phase of ship design is often limited, the methods used to determine the lightship mass must be reliable, fast, and effective. The paper presents and analyzes methods for estimating the lightship mass that are based on empirical data of built ships. Several empirical methods were combined and calibrated to establish the least-squares method which combination gives the value of the lightship mass closest to the one given in the collected database for three types of merchant ships: tankers, bulk carriers, and container ships. The paper presents the results of the calculations of the masses of hull steel, outfitting, machinery, and superstructure. It can be concluded that the presented model for all three types of merchant ships gives satisfactory results.

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