Real-time testing with dynamic substructuring provides an efficient way to simulate the nonlinear dynamic behaviour of civil structures or mechanical facilities. In this technique, the test structure is divided onto two substructures: the relatively crucial substructure is tested physically and the other is modelled numerically in the computer. The key challenge is to ensure that both substructures interact in real-time, in order to simulate the behaviour of the emulated structure. This has special demands on the utilized integration methods and their implementations. Researchers have devoted significant effort to implement second-order integrators, such as Newmark integration methods, in a monolithic way where both substructures are integrated altogether. However, in view of large and complex structures, time integration methods are required to advance large-scale systems hence endowed with high-frequency components of the response or mixed first- and second- order systems like in the case of controlled systems. In this case, the monolithic implementation of a second-order time integration method becomes inefficient or inaccurate. With these promises, the thesis adopts the Rosenbrock-based time integration methods for both dynamic simulations of complex systems and substructure tests, and in particular, focuses on the development of monolithic schemes with subcycling strategies for nonlinear cases and partitioned methods with staggered and parallel solution procedures for linear and nonlinear cases. Initially, the Rosenbrock integration methods endowed with one stage to three stages are introduced and their applicabilities to second-order systems are investigated in terms of accuracy, stability and high-frequency dissipation, such as stability analysis of the Rosenbrock methods with one stage and two stages via the energy approach and numerical experiments on an uncoupled spring-pendulum system. Then, these methods are implemented in a monolithic way for real time substructure tests also considering subcycling strategies. Meanwhile, real-time substructure tests considering nonlinearities both in the numerical and physical substructures were carried out to illustrate the performances of the monolithic methods. Moreover, three types of partitioned algorithms based on the element-to-element partitioning are successively proposed. Two of them are based on acceleration continuity with a staggered solution procedure and a parallel solution procedure, respectively, and one of them is based on velocity continuity and a projection method. Both stability and accuracy properties of the proposed algorithms are examined by means of analytical techniques and numerical studies on single-, two-, three- and four-degree-of-freedom model problems and a coupled spring-pendulum system. Finally, a novel test rig conceived to perform both linear and nonlinear substructure tests with different combinations of numerical and physical substructures are presented and commented.

Base isolation system, as one of the most popular means to mitigate the seismic risks, often exhibits strong nonlinearity. To simplify the procedure of structural design, bilinear force-deformation behavior is recommended for isolation systems in most modern structural codes. Although base isolation system can be analyzed through nonlinear time history method, solving of a system with a large number of degrees of freedom may require an exorbitant amount of time. As a substitute, the equivalent linearization method is frequently used. Apparently, under given earthquake ground motions, the accuracy of equivalent linearization analysis method is significantly related to the estimation of equivalent linear properties. How to improve the estimation accuracy of this approximate method constitutes a subject of wide and deep interest among researchers around the world. In this research, the equivalent linearization analysis method for base-isolated buildings was investigated. The literature survey on related aspects of base-isolated buildings was carried out firstly. Then, the estimation accuracy of fifteen equivalent linearization methods selected from the literatures was evaluated when subjected to twelve earthquake ground motions. After that, from simplicity to complexity, the base-isolated buildings were modeled using single-degree-of-freedom (SDOF) systems and multi-degree-of-freedom (MDOF) systems, respectively. For both considered systems, more comprehensive parametric analyses were performed with varying the parameters selected from the isolation system and the superstructure. Accordingly, improved equivalent linearization methods were derived for SDOF and MDOF systems to improve the prediction accuracy of the maximum displacement of isolation systems. Based on the proposed equivalent linearization methods, different analysis methods for base-isolated buildings were assessed, including equivalent static linear analysis, response spectral analysis, linear and nonlinear time history analyses. It was found that with the proposed equivalent linearization methods equivalent linear analyses could yield more accurate results when compared with the equivalent linearization method recommended by structural codes. As a result, the proposed equivalent linearization method could be potentially useful for the design and analysis of baseisolated buildings, as least in the preliminary stage of structural design.

The main argument of the dissertation is structured around the relationship of innovation and modularity with a special focus on innovation openness. This research took a grasp in understanding the context, the classics, story of Italian design, and Made in Italy at the same time exploring design today: based on a field work in Milan, Lombardy. Case study method proved to be as most suitable for answering the explorative nature of this research. The approach was thus relying on secondary data, desk research and observation for understanding the context both from the angle of tradition and current discourse, as for reaching the next level: collecting cases worth to pursue. The cases presented were chosen to elucidate the targeted questions, and to open the path for further research. However, obstacles faced on the field narrowed the cases covered, and the breadth of the investigation of each case study. Limitations in data access did not allow going beyond the story, I had to rely on what was constructed by the company itself. Despite these obstacles the analysis benefited from the perspective of communication and branding: it made possible to investigate a complex innovation effort. This proved to be a valuable insight, since design-driven industries are driven by producing meanings, forming the discourse where communication plays a key role. This work explores what modularity means in production opening up the perspective toward the aesthetic and semantic realm of production of goods. Furthermore in search for the locus of innovation it examines the relationship of modularity, innovation and openness. By exploring architectural innovation [Henderson and Clark 1990] I found that core design concepts that define the direction of technological improvements enter the conceptual frame of innovation: • What was interpreted as ‘values’ by the company defining the design are proven to be core design concepts in the conceptual frame, as they define here a technological and conceptual [stylistic] frame. • Thus, architecture draws here a semantic and aesthetic frame of conveying meanings. [Not just merely defining the technological construction of the artifact described by the interaction of the elements]. • Procedural innovation [coined by me]: the effort that evolves around the main objective to most efficiently elaborate on the core design concepts in technological, and semantic realms. Further findings of the case studies suggest that open methodology of design and innovation is prone to come from third parties to established firms: • open design methodology as a communication strategy that contributes to innovation practices of the company, and not as a conscious strategy coming from the other way round. Here technological and communication tools are intertwined, as they are conveying meanings defined by the core design concepts • Firms in need for raising their capacities and reshaping organizational routines to innovate turn to third parties in the Knowledge-Intensive Business Services • elucidate hybrid forms of innovation Adding to theory The above-mentioned empirical findings were backed by a concise summary on: • open/ user/ collaborative innovation scholarship • links between modularity and innovation • and understanding the relationship of modular design in the history of design and architecture; also elaborating the: • Semantic frame of innovation: where the product is an architecture of meanings • Framework for understanding stylistic realm of conveying meanings and innovation • Linking modular design of products as a conceptual approach [aesthetics] and linking it to production from an evolutionary perspective Adding empirical insights to be considered for • Organizational theory: namely redefining the boundaries of the firm • Innovation openness: based on the locus of innovation • Modularity: apart from focusing on production, organization and that modular construction of goods has also a conceptual meaning (conceptually exploring the relationship of modular design and integrality with examples from architecture and classics of Italian design). Considering goods as an architecture of meanings and firms producing brands rather than goods, it draws on the implications of arrangement of production.