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PhD projectMy research topic falls within the scope of computational design and digital fabrication. The focus of my thesis will be on additive manufacturing and especially on 4D printing. Furthermore, trough my supervisor, Prof. Ingrid Paoletti, I am currently involved in a project for a 3D printed facade in Dubai for Expo 2020.1. Current scenarioThe last decade set a wide range of urgent and inescapable imperatives: greater awareness of environmental responsibility, energy use and its impact on global warming, the need to take ethical account of materials origin, depletion of resources and building waste \cite{2017}. After 200 years of industrial activities climate change is ravaging the planet with soil degradation, biodiversity loss, global warming  and consequent aggravation of the urban heat island effect \cite{Taha_1997}, rising sea levels, drought, and ocean acidification \citep{zapata-marti2007}. Building sector worldwide accounts for 40% of global energy consumption\citep*{2012a}, at the same time it is expected to reduce consumptions up to 53% by 2030.Furthermore the global economy is in crisis, GDP is slowing all over the world due to the inability of the infrastructure (both digital and physical) to adapt to society demands: in the last 20 years productivity has been declining \cite{rifkin2011}. Thermodynamic laws have been neglected: energy changes form in only one direction and at every step of conversion some energy is lost. Improving the system with better machines and better workers doesn't affect productivity anymore because machines and workers accounts for only 40% of productivity while the rest 60% occurs as a result of aggregate efficiency. However aggregate efficiency has now reached its ceiling in many countries (Japan is leading the world with a mere 20%) because the business is still plugged into a second industrial revolution infrastructure \cite{rifkin2014}. Therefore according to Jeremy Rifkin the key for a new sustainable growth is to raise aggregate efficiency trough the convergence of digitalization, automation and renewability in terms of communication, transportation, energy \cite{economy2018}.Indeed the digital revolution is the enabler of a new era of intelligent, automated, ubiquitous, interactive systems able to sense, manage and compute data and adapt themselves to the environment optimizing resources.1.1 Digital architecture Coming to the architectural world, computational design and digital fabrication are offering an unseen opportunity for redemption in the field of construction, the flexible nature of advance manufacturing technology is more than just an enabler of formal complexity; it is rather leveraged as a chance to replan the whole design-to-production chain \cite{2014}. We often hear about "re-thinking" or "re-inventing" building sector because conventional processes are no more sustainable, not only environmentally but socially and economically as well.Indeed in the broaden context of Industry 4.0, the construction field is implementing its adaptivity trough parametric performative design based on data and digital fabrication machines and tools. The 4th industrial revolution is providing a wide contamination of knowledge in the “age of entanglement” \cite{oxman2016}: the multidisciplinary, or better, according to  \citet{ito2016} antidisciplinary approach breaks the boundaries between disciplines. This allows an extraordinary understanding of the entire construction process: as in the Renaissance the designer has the chance to access, control and manage a large amount of knowledge in the form of data. For instance materials or structural properties are fundamentally embedded in the design phase. Furthermore it is challenging the assumptions that underly mass production allowing “individuals to design and produce tangible objects on demand” \cite{gershenfeld2012} offering then a democratic advanced customization.However, even though the digital revolution is having a deep impact on architecture and construction we are still attached to conventional methods, we 3D print bricks in clay or concrete houses with the same shape we did with traditional architecture, automation is employed as a working force just for its precision and complexity-enabling skills but still we are not fully exploiting such technologies.A new approach is based on material as active generator of architecture materialism \cite{naboni2017}, programmable materials can offer a new paradigm for construction \cite{Tibbits_2012} and hybrid additive processes, according to \citet{Tibbits_2016}, are the future of this field.1.2 Informed matter In conventional design methodology material is often considered as a subordinate attribute of form, \citet{oxman2010} claims it rather represents its progenitor. In fact natural processes such as growth, evolution and self-organisation instead of being considered just as metaphors or digital simulations, they can be employed in physical materials and fabricated systems \cite{Papadopoulou_2017}. This defines generative materiality, material system carries its own inherent genotypic information as well as phenotypic procedural characteristics of joining or assembly \cite{perez2008}. Procedural integration already exists in nature: "The human bone re-accommodates its formal organization (“geometry”), through material distribution (material) according to the magnitude and direction of loads applied to it at any given moment (structure)." (Oxman, 2010)Trough material engineering we have the possibility to understand and know the genotypic genetic heritage of materials and trough computational design we can embed data in material systems as phenotypes.2. AM from 3D to 4DAdditive Manufacturing (AM) is a process of incremental formation executed by the addition of subsequent layers of materials without using supplementary instruments or molds. The main additive fabrication techniques share the same basic principle, in that a solid digital model is sliced into sectional layers then transferred to the manufacturing machine. Physical and chemical processes lead to the creation of solid homogenous forms composed of amorphous materials like liquids, powders, gas and fibers. This process offers a wide degree of flexibility and economic potential because the components are made directly from natural materials. The main advantage comes from the possibility to produce unique components, which would not be economically sustainable to produce with traditional manufacturing techniques. \citep{Naboni_2015}Additive manufacturing is an increasingly growing field and it has now the chance to enable new design strategies and techniques trough research on stimulus-responsive materials and 4D printing. This technology, trough shape shifting behaviors, generate structures that are capable of self-assembly, self-adaptability, self-repair. This brings several advantages, such as significant volume reduction for storage, and easy transformations.4D printing, at the time it was firstly brought to life by Skylar Tibbits, was defined as 3D printing with the addition of time, meaning featuring transformation by time in the object manufactured \cite{hirsch2014} . The last researches on the field have emphasized the importance of materials in the process, hence a more accurate formulation could be: "additive manufacturing of stimulus-responsive materials". Smart materials have been promoted as promising emergent technology and are already widely employed such as in biomedical \citep{Castro_2017}, electronic \citep{Liu_2016} devices and aerospace application.3. Material testing for AMAM is an anisotropic process, therefore it is quite complicated to predict performances of materials under stress, many variables can influence the 3D printed piece's behavior. Additionally, typical material employed in 3D printing such as polymeric compounds are produced with different concentration of colors or fibers that can affect the results. 3.1 Case studyWithin ABC Department we are developing the project of a 3D printed facade for a service pavilion of Expo 2020 in Dubai. Through computational design, the facade concept, consisting in horizontal lamellas in the shape of waves with a complex geometry generation, has been optimized for additive manufacturing.