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Designing an engineering system that is both environmentally and economically sustainable is a challenging task. Designers need to cope with socio-technical uncertainties and design systems to provide high performance during long lifecycles. Flexibility in engineering design provides ways to address such challenges by making engineering systems changeable in the face of uncertainty. It is difficult, however, to identify suitable system elements for designing flexibility, especially when subjected to multiple sources of uncertainty and complex interdependency between socio-technical and systems elements. This paper considers embedding flexibility into the engineering design as a mechanism to ensure better sustainability and to improve economic performance in long-term lifecycles. The main contribution is a novel methodology to identify valuable opportunities to embed flexibility as a way to deal pro-actively with uncertainty in market and environment. The proposed methodology integrates Bayesian network into engineering system design to effectively model complex change propagation in the flexibility identification process. It helps structure concept generation activities by identifying candidate areas to embed flexibility in the system. It compares favorably to other concept generation methods (e.g., prompting, brainstorming) that require modeling and evaluation of a large number of concepts generated in order to identify the ones offering better performance. It differs from other flexibility enabler identification methods by considering indirect as well as direct dependencies, in addition to the probabilistic nature and risk resulting from possible changes. Another contribution is the demonstration application of the proposed methodology through the analysis of a waste-to-energy technology in Singapore based on anaerobic digestion. Results show that the expected net present value of the flexible design concepts provides more than 10 % improvement over a fixed benchmark design in terms of economic lifecycle performance. This design is conducive of better economic sustainability via additional power generation and better use of resources. Results also indicate that the flexible design can reduce downside risks and capitalize on upside opportunities significantly.

The design of engineering systems like airports, communication infrastructures, and real estate projects today is growing in complexity. Designers need to consider socio-technical uncertainties, intricacies, and processes in the long-term strategic deployment and operations of these systems. Flexibility in engineering design provides ways to deal with this complexity. It enables engineering systems to change in the face of uncertainty to reduce impacts from downside scenarios (e.g., unfavorable market conditions) while capitalizing on upside opportunities (e.g., new technology). Many case studies have shown that flexibility can improve anticipated lifecycle performance (e.g., expected economic value) compared to current design and evaluation approaches. It is a difficult process requiring guidance and must be done at an early conceptual stage. The literature offers little guidance on procedures helping designers do this systematically in a collaborative context. This study investigated the effects of two educational training procedures on flexibility (current vs. explicit) and two ideation procedures (free undirected brainstorming vs. prompting) to guide this process and improve anticipated lifecycle performance. Controlled experiments were conducted with ninety participants working on a simplified engineering systems design problem. Results suggest that a prompting mechanism for flexibility can help generate more flexible design concepts than free undirected brainstorming. These concepts can improve performance significantly (by up to 36 %) compared to a benchmark design—even though users did not expect improved quality of results. Explicit training on flexibility can improve user satisfaction with the process, results, and results quality in comparison with current engineering and design training on flexibility. These findings give insights into the crafting and application of simple, intuitive, and efficient procedures to improve lifecycle performance by means of flexibility and performance that may be left aside with existing design approaches. The experimental results are promising toward further evaluation in a real-world setting.

Introduction The decreasing level of physical activity among female undergraduates is worrying as it is associated with the increased risk of non-communicable diseases. Thus, this study aimed to identify the motivations, barriers and preferences towards exercise among female undergraduates in Malaysia. Methods A non-probability purposive sampling was used for the recruitment process. The inclusion criteria of the participants were registered female undergraduates and aged between 18–30 years old. A semi-structured in-depth interview was used to collect topic-related information from the participants and signed consents were obtained prior to the interview. The interview questions were on respondents’ understanding of exercise, motivation and barriers to exercise, and exercise preferences. The recruitment process was conducted until the data was saturated. All interviews were audio recorded and manually transcribed verbatim. NVivo 11 was used to conduct the inductive analysis of the data to develop themes for motivation and barriers to exercise. For exercise preferences, four predetermined themes were used. Findings A total of 26 respondents participated in this study. Eight themes were found for motivation to exercise, with the most common themes being maintaining or improving appearance, health benefits and togetherness. For barriers of exercising, five themes were found, and the most common ones were disliking exercise and no motivation. For exercise preferences, most respondents preferred a structured exercise program with flexibility in terms of when and where the exercise could be conducted. Light or moderate intensity exercise for 10–30 minutes with a frequency of 1–2 times a week was desired the most among the respondents. Conclusion In conclusion, personal and environmental factors play important roles in motivating or hampering female undergraduates to exercise, and a structured program was the preferred mode of exercise of these respondents. A new exercise module was designed based on this needs assessment with a 70% acceptance rate among the participants. These findings can help the future development of more exercise modules tailored to female university students.

The main purpose of this paper was to evaluate the relationship between faculty's flexibility and students' active learning. The population included all MSc students of engineering faculties in Shiraz University. By random classified sampling method 300 students were selected. The instruments included Intellectual Development Subscale of College Student Experiences Questionnaire (Pace & Kuh, 2002), and Personal Style Inventory, PSI (Taggart and Taggart -- Hausladen, 1993). The questionnaires were distributed among the sample and data were entered in SPSS 16 and analyzed. The results of the research showed the average attitudes of the students about their active learning and faculties' flexibility in Shiraz University. In addition, the results indicated that from the students' viewpoints, faculties' flexibility had a significant effect on their active learning.

Thin cylindrical shells are susceptible to cracking under long-term load and external impact, and it is of considerable scientific and technical value to investigate the nonlinear vibration response characteristics and monitor the health condition of the shell structure. Based on the Flügge shell theory, the nonlinear dynamic model for the thin cylindrical shell is established. By the partial Fourier transform combined with the residue theorem, the forced vibration generation and propagation mechanism of the thin cylindrical shell are investigated, and the analytical solution of forced vibration displacement in the space domain is obtained. Then, the local flexibility matrix is derived from the perspective of fracture mechanics, and the continuous coordination condition on both sides of the straight crack is constructed using the linear spring model. Combined with the wave superposition principle, the analytical approach for nonlinear vibration response is proposed to reveal the evolution law of vibration characteristics of the thin cylindrical shell with a straight crack, and then, a straight crack identification method based on natural frequency isolines and amplitude maximization methods is presented. Finally, the effect of various morphological information of the straight crack on the nonlinear vibration response characteristics of the thin cylindrical shell is studied in detail, and a numerical case is conducted to verify the effectiveness of the proposed straight crack identification method.

PurposeThis paper focuses on understanding the contribution of Industry 4.0 technologies to manufacturing flexibility.Design/methodology/approachA multiple-case study was conducted through interviews and complementary data from 12 adopters of Industry 4.0 technologies from the industrial sector. To enable a broad perspective, cases from 5 industry sectors with different technological intensity levels were studied.FindingsThe findings show that Industry 4.0 technologies are mostly used to improve machine flexibility since there is a major focus on technological approaches rather than on wider flexibility. The results also showed that cloud services, IoT, and data analytics provide the basis for flexible operation, and collaborative robots, ERP/MES/PLM, AGVs, and traceability devices are the most commonly implemented technologies for flexibility. However, inherent contingency factors such as production complexity and product life cycle need to be considered.Originality/valueThis article expands the research on manufacturing flexibility, considering new capabilities introduced by Industry 4.0.

Contractual flexibility as an effective way to maintain and increase parties’ relationship quality has been widely introduced to contracting in construction projects. However, conflicting evidences exist regarding their effectiveness on relationship quality based on transaction cost theory. Building on two distinct bases for contractual flexibility: content flexibility, rely on flexible content incorporated in initial contract content, versus executing flexibility, rely on parties’ relationship instead of contract contents, this study examines how contractual flexibility effect relationship quality under different transaction attributes (asset specificity, environmental uncertainty, and behavioral uncertainty). Results from a sample of 312 parties reveal that content flexibility and executing flexibility positively influence relationship quality, with executing flexibility having a stronger association than content flexibility. Yet, important conditions exist. The moderating analysis demonstrates that when asset specificity or environmental uncertainty is high, executing flexibility, not content flexibility, matters more to relationship quality. In contrast, when behavioral uncertainty is high, content flexibility, not executing flexibility, matters more to relationship quality. These findings suggest that contractual managers should incorporate executing flexibility into contracts more sufficiently, and the appropriate contractual flexibility should match with transaction attributes.