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This research presents a design method for designing greenhouse structures based on topology optimization. Moreover, the structural design of a gothic greenhouse is proposed in which its structural strength has been improved by using this proposed method. In this method, the design of the structure is done mathematically; therefore, in the design process, more attention can be focused on the constraint space and boundary conditions. It was also shown how the static reliability and fatigue coefficients will change as a result of the design of the greenhouse structure with this method. Another purpose of this study is to find the weakest part of the greenhouse structure against lateral winds and other general loads on the greenhouse structure.

In the proposed method, the outer surface and the allowable volume as a constraint domain were considered. The desired loads can be located on the constraint domain. The topology optimization was used to minimize the mass and structural compliance as the objective function. The obtained volume was modified for simplifying the construction. The changes in the shape of the greenhouse structure were investigated by choosing three different penalty numbers for the topology optimization algorithm. The final design of the proposed structure was performed based on the total simultaneous critical loads on the structure. The results of the proposed method were compared in the order of different volume fractions. This showed that the volume fraction approach can significantly reduce the weight of the structure while maintaining its strength and stability.

Topology optimization results showed different strut and chords composition because of the changes in maximum mass limit and volume fraction. The results showed that the fatigue was more hazardous, and it decreased the strength of structure nearly three times more than a static analysis. Further, it was noticed that how the penalty numbers can affect topology optimization results. An optimal design based on topology optimization results was presented to improve the proposed greenhouse design against destruction and demolition. Furthermore, this study shows the most sensitive part of the greenhouse against the standard loads of wind, snow, and crop.

The obtained designs were compared with a conventional arch greenhouse, and then the structural performances were shown based on standard loads. The results showed that in designing the proposed structure, the optimized changes increased the structure strength against the standard loads compared to a simple arch greenhouse. Moreover, the stress safety factor and fatigue safety factor because of different designs of this structure were also compared with each other.

The main objective of this study is to present a conceptual model of sustainable product service supply chain (SPSSC) performance assessment in the oil and gas industry.

Based on an in-depth study of the previous literature, the indicators related to PSSC performance assessment were determined. Then, exploratory factor analysis and confirmatory factor analysis were applied to identify and confirm the sub-criteria and criteria pertaining to the proposed model.

The obtained results identify ten criteria related to the proposed model as follows: “Environmental performance”, “Customer performance”, “financial performance”, “Information technology Performance”, “Social Performance”, “Risk performance”, “Logistics performance”, “Operational performance”, “Organizational performance” and “performance of innovation and growth”.

As the present research was conducted in the Iranian context, caution should be taken regarding the generalizability of the obtained results.

Based on a set of the identified criteria, this study proposes a conceptual model of the PSSC performance assessment in the oil and gas industry which hopefully could be useful for other organizations in this industry and other organizations in other parts of the world.