Search

In this paper, combined effects of material degradation, p-delta, and foundation uplift are incorporated in a soil-structure-interaction (SSI) framework to assess seismic response of a single-degree-of-freedom system. The considered phenomenological systems represent a column with a lumped mass on top is placed on a rigid foundation. The foundation is mounted on Winkler springs and dashpots to take account of soil-foundation compliance and material/radiation damping. The springs are tensionless to guarantee that uplift is properly modelled. The model is verified for two specific limit cases with the code and literature to make sure that the model is capable of capturing SSI and foundation uplift. Three sets of flexural degradations for capturing nonlinear performance of the column are defined to be categorized as low, moderate, and high degradation levels. The response of each system is then compared to the corresponding one with the elastic–perfectly plastic (EPP) material behavior. More than 150,000 analyses are conducted for several dimensionless parameters and twenty time history ground motions. The results including elastic and inelastic displacement ratios are finally compared with those stipulated by seismic codes for shallow foundations with the flexible-based condition. The results reveal that material degradation can significantly increase the displacement ratios of soil-structure systems and in some cases can lead to structural instability, which cannot be captured by conventional EPP models. More specifically, displacement ratios calculated in accordance with ASCE41-17 by assuming fixed-base model and incomplete data about level of material degradation might be underestimated, once compared to the results of more realistic conditions.

The automotive industry is one of the main industries in the world that employs nearly 10% of the entire workforce by considering its supply chain. Stakeholders and regulatory agencies persuade the automotive supply chain industry to obtain green because of increasing environmental problems related to social concerns and global warming. Suppliers play a leading role in the management of the supply chain, but may fail to correctly take part in these initiatives. The goal of this paper is to develop a conceptual model to evaluate the supplier’s role in green initiatives by probing possible drivers, such as customer investment, customer requirements, relational norms, and supplier readiness in the Iranian automotive industry. The government of Iran is trying to focus on more localization by entering the best bets in the automotive market and collaborating with local suppliers and Original Equipment Manufacturers as the government has planned to restrict Completely Built Unit imports. This research has collected data from 150 Iranian automotive suppliers in order to examine and develop a framework and hypotheses using the Partial least squares method. Based on the final results, it can be concluded that the most significant drivers that play a leading role in supplier participation are society, environmental regulations, customer investment, and customer requirements. In contrast, supplier readiness and relational norms did not have a considerable effect on supplier participation. Our investigation is the first work to assess GSCM practices in the automotive industry in Iran.

Firm’s efficiency and competitiveness are two important challenges in today’s global market that have motivated many manufacturing firms to plan novel manufacturing management strategies. Nowadays, simulation models have been used to assess different aspects of manufacturing systems. This paper introduces a welding unit of a manufacturing line of heater production as a case study and the basic application of the ARENA software. The main goal of this paper is increasing the productivity of the production line by using computer simulation. To achieve this goal, three various scenarios are compared and suggested to obtain the better improvement in productivity.