Modular precast construction is a methodological approach to reduce environmental impacts and increase productivity when building with concrete. Constructions are segmented into similar precast concrete elements, prefabricated with integrated quality control, and assembled just-in-sequence on site. Due to the automatised prefabrication, inaccuracies are minimised and the use of high-performance materials is enabled. As a result, the construction process is accelerated, and the modules can be designed to be lightweight and resource-efficient. This contribution presents the fundamentals of modular constructions made from precast concrete components. Then, to elaborate the requirements of a contemporary modular precast construction, the historic developments are described. Further, concepts and technical processes–comprehensible to non-expert readers–are introduced to formalise the discussion about the current state-of-the-art methods. Three case studies treating ongoing research are introduced and related to the conceptual fundamentals. The research is evaluated with regard to current barriers and future directions. In conclusion, modular precast construction is able to reduce emissions and increase productivity in the sector if researchers and firms coordinate the development of suitable technologies that bring value to critical stakeholders.

Building in heavy rain is seldom beneficial, but common practice on site. It promotes inaccuracies and impairs the use of modern but sensible high‐performance materials and costs time, since disruption in construction frequently causes complicated returns to the planning process. Nevertheless, a handcrafted production process is still considered the one and only alternative since all buildings are unique and thus must be manually constructed on site. Indeed? The priority program entitled “Adaptive modularized constructions made in a flux” funded by the German Research Foundation follows a completely new approach. Buildings are divided into similar modular precast concrete elements, prefabricated in flow production, quality‐assured, and just‐in‐time assembled on site. Comparable to puzzles with many pieces, the uniqueness of the structure is maintained. The motto is: “Individuality on a large scale‐similarity on a small scale”. The contribution presents approaches of modularization, production concepts, and linking digital models. Serial, stationary prefabrication enables short production times and resource‐efficient modules that are assembled to load‐bearing structures with low geometrical deviations. Stringent digitalization ensures high quality of all intermediate steps. These comprise fabrication, assembly, and the whole service life of the structure. The result is a lean production process.

Multi-material design as a method of lightweight construction enables the targeted use of materials in a component by utilizing the individual material properties. However, this advantage comes with additional challenges for the product developer, such as the increased effort involved in identifying the design. Multi-material topology optimization is a method that can support the product developer in creating initial weight-optimized component designs in multi-material design in early phases. In addition, several state-of-the-art studies show that the position of the interfaces between the materials has an influence on the strength of the optimization result. These investigations took place in 2D and developed optimization methods which largely use non-linear building blocks, such as cohesive behavior. The non-linear components lead to an increase in computational effort and a reduction in the robustness of the optimization. In this article, a method for the consideration of adhesive-bonded interfaces in multi-material topology optimization in 3D by means of an objective function is developed. For this purpose, requirements are derived based on an analysis of the different load cases of a bond and these are used to create the method. The method is then successfully validated by means of two numerical experiments. In addition, the influence of a newly introduced parameter on the optimization results is investigated by means of a parameter study.

In the laser powder bed fusion process (PBF-LB), components are built up incrementally by locally melting metal powder with a laser beam. This process leads to inhomogeneous material properties of the manufactured components. By integrating these specific material properties into a topology optimization algorithm, product developers can be supported in the early phases of the product development process, such as design finding. For this purpose, a topology optimization method was developed, which takes the inhomogeneous material properties of components fabricated in the PBF-LB process into account. The complex pore architecture in PBF-LB components was studied with micro-computed tomography (µCT). Thereby, three characteristic regions of different porosity were identified and analyzed. The effective stiffness in each of these regions was determined by means of resonant ultrasonic spectroscopy (RUS) as well as finite element analysis. Afterward, the effective stiffness is iteratively considered in the developed topology optimization method. The resulting design proposals of two optimization cases were analyzed and compared to design proposals derived from a standard topology optimization. To evaluate the developed topology optimization method, the derived design proposals were additionally manufactured in the PBF-LB process, and the characteristic pore architecture was analyzed by means of µCT.

As a method of lightweight design, multi-material design aims to make targeted use of materials in order to reduce CO2 emissions. In this context, it can be described as one of the product development methods used to meet the challenges of climate change. However, since the design of structures in multi-material design is complex, topology optimization can be used to support the product developer. In this article, a multi-material topology optimization method is developed that combines the Velocity Field Level Set method with the Reconciled Level Set method. Furthermore, the current design is explicitly resolved in each iteration by means of multi-material remeshing. The edge collapse phase in the remeshing process is achieved by applying the producer consumer pattern. The developed method is then validated using known examples from the state of research and the influence of parameters of the method on the result is analyzed by means of studies.