scholarly journals Design Implications and Opportunities of Considering Fatigue Strength, Manufacturing Variations and Predictive LCC in Welds

Metals ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1527
Author(s):  
Mathilda Karlsson Hagnell ◽  
Mansoor Khurshid ◽  
Malin Åkermo ◽  
Zuheir Barsoum
Keyword(s):  
Life Cycle ◽  
Fatigue Strength ◽  
Life Cycle Cost ◽  
Design Stage ◽  
Direct Result ◽  
Welded Structures ◽  
Early Design Stage ◽  
Repair Costs ◽  
Welded Structure ◽  
Cost Reductions

Fatigue strength dictates life and cost of welded structures and is often a direct result of initial manufacturing variations and defects. This paper addresses this coupling through proposing and applying the methodology of predictive life-cycle costing (PLCC) to evaluate a welded structure exhibiting manufacturing-induced variations in penetration depth. It is found that if a full-width crack is a fact, a 50% thicker design can result in life-cycle cost reductions of 60% due to reduced repair costs. The paper demonstrates the importance of incorporating manufacturing variations in an early design stage to ensure an overall minimized life-cycle cost.

An intelligent system for estimating full product Life Cycle Cost at the early design stage

2008 ◽  
Vol 3 (2/3) ◽  
pp. 96 ◽  
Author(s):  
Haifeng Liu ◽  
Vivekanand Gopalkrishnan ◽  
Wee Keong Ng ◽  
Bin Song ◽  
Xiang Li
Keyword(s):  
Life Cycle ◽  
Life Cycle Cost ◽  
Product Life Cycle ◽  
Intelligent System ◽  
Design Stage ◽  
Product Life ◽  
Early Design ◽  
Early Design Stage

scholarly journals An Automated Procedure for Assessing Local Reliability Index and Life-Cycle Cost of Alternative Girder Bridge Design Solutions

2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Ilaria Venanzi ◽  
Riccardo Castellani ◽  
Laura Ierimonti ◽  
Filippo Ubertini
Keyword(s):  
Life Cycle ◽  
Life Cycle Cost ◽  
Design Solution ◽  
Bridge Design ◽  
Limit States ◽  
Technical Standards ◽  
Local Character ◽  
Repair Costs ◽  
Design Solutions ◽  
Girder Bridge

Stakeholders of civil infrastructures have to usually choose among several design alternatives in order to select a final design representing the best trade-off between safety and economy, in a life-cycle perspective. In this framework, the paper proposes an automated procedure for the estimation of life-cycle repair costs of different bridge design solutions. The procedure provides the levels of safety locally guaranteed by the selected design solution and the related total life-cycle cost. The method is based on the finite element modeling of the bridge and uses design traffic models as suggested by international technical standards. Both the global behavior and the transversal cross section of the bridge are analyzed in order to provide local reliability indexes. Several parameters involved in the design, such as geometry and loads and materials’ characteristics, are considered as uncertain. Degradation models are adopted for steel carpentry and rebars. The application of the procedure to a road bridge case study shows its potential in providing local safety levels for different limit states over the entire lifetime of the bridge and the life-cycle cost of the infrastructure, highlighting the importance of the local character of the life-cycle cost analysis.

Fussy Assessment of Fatigue Strength of Spot-Welded Structures

2012 ◽  
Vol 562-564 ◽  
pp. 2030-2033
Author(s):  
Yu Xin Yao ◽  
Chun Yuan Shi
Keyword(s):  
Fatigue Life ◽  
Fatigue Strength ◽  
Standard Specimen ◽  
Point Of View ◽  
Fuzzy Mathematics ◽  
Welded Structures ◽  
Coupling Relationship ◽  
Welded Structure ◽  
Assessment Result ◽  
Spot Welded

From the point of view of the objective and scientific design of spot-welded structures, each factor that influences the fatigue strength of the spot-welded structure is quantitatively analyzed using fuzzy mathematics. The weighing coefficient is calculated based on the contribution of each factor and their coupling relationship using DARE method. All the influencing factors are divided to two levels, and quantitative assessment result is obtained. Finally, the fatigue life curve of the spot-welded structure is predicted with the utilization of the fatigue life curve of a standard specimen made of the same material.

scholarly journals Test sequencing problem arising at the design stage for reducing life cycle cost

2013 ◽  
Vol 26 (4) ◽  
pp. 1000-1007 ◽  
Author(s):  
Shigang Zhang ◽  
Zheng Hu ◽  
Xisen Wen
Keyword(s):  
Life Cycle ◽  
Life Cycle Cost ◽  
Design Stage ◽  
Sequencing Problem

Design for maintenance: new algorithmic approach

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Oussama Adjoul ◽  
Khaled Benfriha ◽  
Améziane Aoussat
Keyword(s):  
Genetic Algorithms ◽  
Life Cycle ◽  
Life Cycle Cost ◽  
Multicomponent System ◽  
Systems Design ◽  
Simultaneous Optimization ◽  
Product Architecture ◽  
Design Stage ◽  
Content Type ◽  
Optimal Maintenance

PurposeThis paper proposes a new simultaneous optimization model of the industrial systems design and maintenance. This model aims to help the designer in searching for technical solutions and the product architecture by integrating the maintenance issues from the design stage. The goal is to reduce the life-cycle cost (LCC) of the studied system.Design/methodology/approachLiterature indicates that the different approaches used in the design for maintenance (DFM) methods are limited to the simultaneous characterization of the reliability and the maintainability of a multicomponent system as well as the modeling of the dynamic maintenance. This article proposes to go further in the optimization of the product, by simultaneously characterizing the design, in terms of reliability and maintainability, as well as the dynamic planning of the maintenance operations. This combinatorial characterization is performed by a two-level hybrid algorithm based on the genetic algorithms.FindingsThe proposed tool offers, depending on the life-cycle expectation, the desired availability, the desired business model (sales or rental), simulations in terms of the LCCs, and so an optimal product architecture.Research limitations/implicationsIn this article, the term “design” is limited to reliability properties, possible redundancies, component accessibility (maintainability), and levels of monitoring information.Originality/valueThis work is distinguished by the use of a hybrid optimization algorithm (two-level computation) using genetic algorithms. The first level is to identify an optimal design configuration that takes into account the LCC criterion. The second level consists in proposing a dynamic and optimal maintenance plan based on the maintenance-free operating period (MFOP) concept that takes into account certain criteria, such as replacement costs or the reliability of the system.

EFFECT OF FATIGUE TEST ON SPOT WELDED STRUCTURAL JOINT

2017 ◽  
Vol 79 (5-2) ◽  
Author(s):  
Mohammad Khalid Wahid ◽  
Muhammad Nabil Muhammed Sufian ◽  
Mohamed Saiful Firdaus Hussin
Keyword(s):  
Life Cycle ◽  
Fatigue Life ◽  
Fatigue Strength ◽  
Spot Welding ◽  
Fatigue Testing ◽  
Fatigue Stress ◽  
Component Design ◽  
Welded Structure ◽  
Different Thickness ◽  
Spot Welded

Spot welding is mainly used method in joining sheet metals for body structure in automotive industry. The comprehension of the fatigue strength for the spot welds is very critical in automotive component design. Parameter for the resistance spot welding and fatigue machines is constant for each specimen used. The S-N curve is obtained from the fatigue testing for each specimen. This experiment parameters are varies the different thickness and different material combination in spot welding structure to investigate the fatigue life cycle and fatigue stress. For 1050A aluminium joint, fatigue life cycle and fatigue strength will decrease from number of cycle 500 at 16.58 MPa to number of cycle 61 at 6.62 MPa as the thickness increase. The fatigue life cycle and fatigue stress for galvanized iron will increase from number of cycle  46 at 9.25 MPa to number of cycle  1500 at 57.8 MPa when the thickness of joint increase. The finding from the combination of 1050A aluminum and galvanized iron on spot welded structure has shown no improvement in term of fatigue life cycle and fatigue strength because specimens experienced failure at number of cycle 19 with fatigue stress 2.36 MPa.

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