scholarly journals A Lifecycle Cost-Driven System Dynamics Approach for Considering Additive Re-Manufacturing or Repair in Aero-Engine Component Design

2019 ◽  
Vol 1 (1) ◽  
pp. 1343-1352
Author(s):  
Lydia Lawand ◽  
Khalil Al Handawi ◽  
Massimo Panarotto ◽  
Petter Andersson ◽  
Ola Isaksson ◽  
...  
Keyword(s):  
Additive Manufacturing ◽  
System Dynamics ◽  
Development Stage ◽  
Life Extension ◽  
Design Decisions ◽  
Component Design ◽  
Design Variables ◽  
Engine Component ◽  
Aero Engine ◽  
The Impact

AbstractAero-engine component design decisions should consider re-manufacturing and/or repair strategies and their impact on lifecycle cost. Existing design approaches do not account for alternative production technologies such as the use of additive manufacturing in life extension processes. This paper presents a modeling and optimization methodology for examining the impact of design decisions in the early development stage on component lifecycle cost during the in-service phase while considering the potential use of additive manufacturing in life extension strategies. Specifically, a system dynamics model is developed to assess different end-of-life scenarios. Finally, an optimization problem is formulated and solved to minimize lifecycle cost with respect to design variables related to re-manufacturing.

A Simplified Method to Evaluate the Impact of Component Design on Engine Performance

2007 ◽  
Author(s):  
Francesco Montella ◽  
J. P. van Buijtenen
Keyword(s):  
Design Process ◽  
Engine Performance ◽  
Simulation Software ◽  
Fast Method ◽  
Engine Simulation ◽  
Engine Model ◽  
Component Design ◽  
Wide Range ◽  
Engine Component ◽  
The Impact

This paper presents a simplified and fast method to evaluate the impact of a single engine component design on the overall performance. It consists of three steps. In the first step, an engine system model is developed using available data on existing engines. Alongside the cycle reference point, a sweep of operating points within the flight envelop is simulated. The engine model is tuned to match a wide range of conditions. In the second step, the module that contains the engine component of interest is analyzed. Different correlations between the component design and the module efficiency are investigated. In the third step, the deviations in efficiency related to different component configurations are implemented in the engine baseline model. Eventually, the effects on the performances are evaluated. The procedure is demonstrated for the case of a two-spool turbofan. The effects of tip leakage in the low pressure turbine on the overall engine performance are analyzed. In today’s collaborative engine development programs, the OEMs facilitate the design process by using advanced simulation software, in-house available technical correlations and experience. Suppliers of parts have a limited influence on the design of the components they are responsible for. This can be rectified by the proposed methodology and give subcontractors a deeper insight into the design process. It is based on commercially available PC engine simulation tools and provides a general understanding of the relations between component design and engine performance. These relations may also take into account of aspects like production technology and materials in component optimization.

Negotiation in Constraint-Based Design

1996 ◽  
Vol 118 (4) ◽  
pp. 470-477 ◽  
Author(s):  
A. Kusiak ◽  
J. Wang ◽  
D. W. He
Keyword(s):  
Design Problem ◽  
Quantitative Relationship ◽  
Qualitative Reasoning ◽  
Negotiation Process ◽  
Multiple Perspectives ◽  
Design Decisions ◽  
Negotiation Strategies ◽  
Design Variables ◽  
Design Changes ◽  
The Impact

A design problem usually involves multiple perspectives, each with own set of constraints that may interact. The objective of this paper is to develop a methodology to assist in negotiation of constraints from multiple perspectives. The proposed approach is based on qualitative reasoning that provides each perspective with negotiation information for making design decisions. A qualitative constraint network is used to characterize the qualitative and quantitative relationship between design variables. It provides means for tracking dependencies among perspectives for a set of constraints and determines the impact of design changes. When a conflict occurs, effective negotiation strategies are generated. A negotiation procedure for an ill-structured negotiation process is presented. The effectiveness of the negotiation process is improved with the procedure proposed. A valve design problem illustrates the concepts discussed in the paper.

Engine Component Life Prediction Methodology for Conceptual Design Investigations

1986 ◽  
Author(s):  
John D. Cyrus
Keyword(s):  
Life Prediction ◽  
Preliminary Design ◽  
Design Decisions ◽  
Turbine Engine ◽  
Detailed Consideration ◽  
Engine Design ◽  
Engine Component ◽  
Fundamental Understanding ◽  
Engine Components ◽  
The Impact

The increasing emphasis on engine durability requires that an analytical capability be acquired to assess engine component lives during the conceptual/preliminary design phases. A generalized methodology has been developed to provide a fundamental understanding of the impact of engine design decisions, material selections, and a detailed consideration of engine usage for critical gas turbine engine components.

Development and model-based calibration of the lateral controllers “steer-by-angle” and “steer-by-torque” of a lane keeping assistance system

2021 ◽  
pp. 095440702098743
Author(s):  
Timo Stubler ◽  
Matthias Niegl ◽  
Martin Förster ◽  
Peter E Pfeffer ◽  
Ravi Abhishek
Keyword(s):  
Early Development ◽  
Performance Optimization ◽  
Controller Design ◽  
Decisive Role ◽  
Development Stage ◽  
Driver Assistance Systems ◽  
Design Variables ◽  
Straight Line ◽  
Lane Keeping ◽  
The Impact

Advanced Driver Assistance Systems (ADAS) such as Lane Keeping Assistance (LKA) systems are in the focus of current vehicle developments. Of special interest is the calibration task, which plays an increasingly decisive role in early development stages. At this point it is essential to analyze the pre-calibrated controller concepts by appropriate simulation methods. A software toolchain is introduced, using Model-in-the-Loop (MiL) for the evaluation and calibration of the LKA system. Within, a Design-of-Experiment (DoE) tool is integrated together with the simulation environment. This enables the examination of the two different lateral controller concepts Steer-by-Angle (SbA) and Steer-by-Torque (SbT). Their lateral guidance performance is characterized by Key Performance Indicators (KPI), which are derived from simulation quantities of straight-line and cornering maneuvers. Further, statistical behavior models are generated based on those KPI and controller design variables (DV). The subsequent optimization process leads to high performances of both controllers. In particular, the SbA controller shows higher efficiency under the impact of disturbances as well as the reference reaction with lower settling times. Overall, the achieved lateral guidance performances indicate the potential of both control algorithms in an early development stage. With the software toolchain, a platform for further LKA system calibration and lateral guidance performance optimization is established.

scholarly journals System Dynamics Modeling in Additive Manufacturing Supply Chain Management

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 982
Author(s):  
Jairo Nuñez Rodriguez ◽  
Hugo Hernando Andrade Sosa ◽  
Sylvia Maria Villarreal Archila ◽  
Angel Ortiz
Keyword(s):  
Supply Chain ◽  
Additive Manufacturing ◽  
System Dynamics ◽  
Raw Material ◽  
Flow Diagram ◽  
Disruptive Technology ◽  
Chain Management ◽  
Starting Point ◽  
Operating Policies ◽  
The Impact

A system dynamics model was developed with the primary purpose of visualizing the behavior of a supply chain (SC) when it adopts a disruptive technology such as additive manufacturing (AM). The model proposed a dynamic hypothesis that defines the following issue: what is the impact of the AM characteristics and processes in the SC? The model was represented through a causal diagram in thirteen variables related to the SC, organized in two feedback cycles and a data flow diagram, based mainly on the three-essential links of the SC and the order display traceability: supplier–focal manufacturer–distribution Network. Once proposed, the model was validated through the evaluation of extreme conditions and sensitivity analysis. As a result, the dynamic behavior of the variables that condition the chain management was analyzed, evidencing reduction times in production, especially in products that require greater complexity and detail, as well as reductions in inventories and the amount of raw material due to production and storing practices from AM. This model is the starting point for alternative supply chain scenarios through structural operating policies and operating policies in terms of process management.

Designing a Virtual Enterprise Architecture using Structured System Dynamics

2006 ◽  
Vol 25 (1) ◽  
pp. 13-29
Author(s):  
Nikitas A. Assimakopoulos ◽  
Anastasios N. Riggas
Keyword(s):  
System Dynamics ◽  
Enterprise Architecture ◽  
Business Processes ◽  
Core Competencies ◽  
Virtual Enterprise ◽  
Business Goals ◽  
Starting Point ◽  
Efficient Integration ◽  
Structured System ◽  
The Impact

The starting point for establishing a Virtual Enterprise is a set of existing enterprises which might contribute with some of their functionalities (core competencies) to the formation of the virtual entity. The most important issue, in this formation, is the rapid integration of the business processes of the participating companies. The architecture of the VE must assist companies desiring to enter into a virtual relationship by defining the functions and interfaces of critical business processes, thus allowing for a more rapid and efficient integration of the expertise which will be contributed by each partner in the virtual enterprise. While the integration of computer and communication technologies are no doubt critical issues, the successful attainment of the business goals of the virtual enterprise often depends on its ability to align the business processes and practices of partner enterprises. Focus of this paper, is the presentation of Structured System Dynamics (SSPS) multi-methodology for the design and the evaluation of a Virtual Enterprise Architecture. SSPS uses Systems Thinking and System Dynamics principles as launch pad for its approach. The Systemic Methodologies of Problem Structuring Methodology (PSM) and SAST are also integrated in this new Multi-Methodology. SSPS is a new practical and scientific tool in designing and evaluating a VE architecture providing the ability to determine the impact, reliability, success of the Architectures' models created, refine them and identify potential process improvements. A framework for the rapid and efficient integration of the business processes of the participating companies in the virtual enterprise is provided. For this multi-methodology, a real-life application is also presented for a Virtual Enterprise that constructs Wireless Payment Mechanisms.

scholarly journals Exogenous application of growth stimulators improves the condition of maize exposed to soil drought

2021 ◽  
Vol 43 (4) ◽  
Author(s):  
Agnieszka Ostrowska ◽  
Maciej T. Grzesiak ◽  
Tomasz Hura
Keyword(s):  
Plant Growth ◽  
Developmental Stages ◽  
Aminolevulinic Acid ◽  
Stem Elongation ◽  
Development Stage ◽  
Photochemical Activity ◽  
Soil Drought ◽  
Beneficial Effects ◽  
Induced Changes ◽  
The Impact

AbstractSoil drought is a major problem in plant cultivation. This is particularly true for thermophilic plants, such as maize, which grow in areas often affected by precipitation shortage. The problem may be alleviated using plant growth and development stimulators. Therefore, the aim of the study was to analyze the effects of 5-aminolevulinic acid (5-ALA), zearalenone (ZEN), triacontanol (TRIA) and silicon (Si) on water management and photosynthetic activity of maize under soil drought. The experiments covered three developmental stages: three leaves, stem elongation and heading. The impact of these substances applied during drought stress depended on the plant development stage. 5-ALA affected chlorophyll levels, gas exchange and photochemical activity of PSII. Similar effects were observed for ZEN, which additionally induced stem elongation and limited dehydration. Beneficial effects of TRIA were visible at the stage of three leaves and involved leaf hydration and plant growth. A silicon preparation applied at the same developmental stage triggered similar effects and additionally induced changes in chlorophyll levels. All the stimulators significantly affected transpiration intensity at the heading stage.

scholarly journals Long-term effectiveness of elderly health care voucher scheme strategies: a system dynamics simulation analysis

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ka Chun Chong ◽  
Hong Fung ◽  
Carrie Ho Kwan Yam ◽  
Patsy Yuen Kwan Chau ◽  
Tsz Yu Chow ◽  
...  
Keyword(s):  
Primary Care ◽  
Chronic Disease ◽  
Public Sector ◽  
System Dynamics ◽  
The Elderly ◽  
Healthcare Services ◽  
Dynamics Simulation ◽  
Public And Private ◽  
The Public ◽  
The Impact

Abstract Background The elderly healthcare voucher (EHCV) scheme is expected to lead to an increase in the number of elderly people selecting private primary healthcare services and reduce reliance on the public sector in Hong Kong. However, studies thus far have reported that this scheme has not received satisfactory responses. In this study, we examined changes in the ratio of visits between public and private doctors in primary care (to measure reliance on the public sector) for different strategic scenarios in the EHCV scheme. Methods Based on comments from an expert panel, a system dynamics model was formulated to simulate the impact of various enhanced strategies in the scheme: increasing voucher amounts, lowering the age eligibility, and designating vouchers for chronic conditions follow-up. Data and statistics for the model calibration were collected from various sources. Results The simulation results show that the current EHCV scheme is unable to reduce the utilization of public healthcare services, as well as the ratio of visits between public and private primary care among the local aging population. When comparing three different tested scenarios, even if the increase in the annual voucher amount could be maintained at the current pace or the age eligibility can be lowered to include those aged 60 years, the impact on shifts from public-to-private utilization were insignificant. The public-to-private ratio could only be marginally reduced from 0.74 to 0.64 in the first several years. Nevertheless, introducing a chronic disease-oriented voucher could result in a significant drop of 0.50 in the public-to-private ratio during the early implementation phase. However, the effect could not be maintained for an extended period. Conclusions Our findings will assist officials in improving the design of the EHCV scheme, within the wider context of promoting primary care among the elderly. We suggest that an additional chronic disease-oriented voucher can serve as an alternative strategy. The scheme must be redesigned to address more specific objectives or provide a separate voucher that promotes under-utilized healthcare services (e.g., preventive care), instead of services designed for unspecified reasons, which may lead to concerns regarding exploitation.

On the Impact of Discrete Secondary Controllers on Power System Dynamics

2021 ◽  
pp. 1-1
Author(s):  
Taulant Kerci ◽  
Mohammed Ahsan Adib Murad ◽  
Ioannis Dassios ◽  
Federico Milano
Keyword(s):  
Power System ◽  
System Dynamics ◽  
Power System Dynamics ◽  
The Impact
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