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Free-form concrete panel production requires an increasing amount of manpower because the molds cannot be reused. There are many limitations when it comes to reproducing accurate forms due to the many manual processes. Therefore, the current study developed side mold control equipment that can automatically fabricate molds for free-form concrete panels. The equipment is capable of molding various shapes and sustainable operation. However, there may be errors as it automatically produces various shapes. Therefore, it is necessary to check the errors between manufactured shapes and designed shapes. The shape created using the side mold control equipment showed less than 0.1° error in side angle and ±3 mm error in side length. Therefore, the equipment manufactured a precise shape. Based on the findings of the study, the side mold control equipment will be used to produce accurate shape of free-form concrete panels automatically.

FCP (Free-form Concrete Panel) is used to easily realize the huge and complex curved surfaces of free-form buildings, and research on FCP manufacturing technology is being conducted. However, as the concrete was extruded manually into the manufactured mold, the precision of the FCP was lowered and errors occurred. Therefore, this study developed concrete extrusion equipment that includes a nozzle part, an open/close part, and a control part, according to the required performance derived from previous research analysis. The mixing ratio of concrete was selected at an appropriate value of W/C 38% and extruded uniformly with a width of 60 mm and a thickness of 22 mm. Depending on the opening/closing function, it was possible to open and close at the desired position. The concrete extrusion nozzle for FCP production is the basic equipment, and miniaturization and automation of the nozzle are required in the future. This is expected to contribute to the development of new free-form construction technology and equipment.

With the development of technology, the number of free-form structures—as well as their value—is increasing. In order to construct such free-form structures, a number of studies are being conducted on free-form molds from multifaceted perspectives. However, it is difficult to identify the progress of studies related to free-form molds, as the scope of the studies is redundant or similar in many cases. Therefore, the current study focused on the identification of the trends of preceding studies on free-form molds using the PRISMA technique. The study classified the studies into three topics in order to identify the trends: ‘free-form curve fabrication technology’, ‘free-form mold fabrication technology’, and the ‘analysis of free-form panel forms.’ Each topic was further categorized into two tiers for more in-depth analysis. The whole process was adopted in order to suggest the trends of studies on free-form molds. The findings are expected to be used to provide fundamental data for future studies on free-form molds, and to set the directions for new studies.

Many studies have been conducted for the accuracy of free-form concrete panel fabrication, but there still are errors in the process of fabrication. This study developed a connection technology of detachable shape part that can be applied to the existing multi-point Computer Numerical Control (CNC) to enhance the accuracy of fabrication. The detachable type can place a silicone plate on top of the rod without additional fixtures. The accuracy of the technology was verified by curvature test and free-form concrete panel fabrication test. Three curves were created to compare the discrepancies between the designed shapes and the fabricated shapes through quality test. As a result, the detachable type decreased the error by up to 2 mm. In addition, a panel was fabricated to analyze the error to verify the rigidity of the developed molds. The error caused by concrete deflection under load or the error caused by repeated fabrication was about 0.5 mm. The shape error was within 3.5 mm. This small error proved greater accuracy compared to the existing technology.

Errors that occur on the side shape of Free-form Concrete Panels (FCP) can cause errors in the FCP construction stage. Therefore, the error generated in FCPs must be reduced. Accordingly, side mold development and research are being carried out. However, in the case of studies using side silicone molds, there was no detailed information about the specifications and application methods of molds, and there was no support between molds. When producing FCPs with the method stated above, there is a high possibility for the mold to be pushed due to the side pressure of concrete, which can cause errors on the side shape of FCPs. Therefore, two new types of side silicone molds were developed in this study. In order to verify the performance difference between the newly developed mold and existing molds, FCP production tests and error analysis were performed. In result, the developed mold decreased the average error difference of the FCP side by 3–5 times compared to the existing mold. In addition, the significance of the average error difference with the produced FCP was verified, and results showed that the difference of the average error was significant at a 95% confidence level.

Free-form design may enhance the architectural value of buildings in terms of aesthetic and symbolic effects. However, it is difficult to reuse the mold of free-form concrete segments, so they are manufactured for single use. Manufacturing these molds is a time-consuming process that requires a lot of manpower. To solve these problems, there have been numerous studies on the use of phase change materials (PCMs) to make the molds. PCM molds represent a new technique of producing free-form panels using a computerized numeric control (CNC) machine that employs low-cost material to produce free-form concrete panels. However, PCM molds require a substantial amount of time and energy during fabrication because repeated heating and cooling cycles are required during panel production, and this process increases the CO2 emissions. Thus, the purposes of this study were to develop composite molds using aluminum powder to improve PCM mold performance and to conduct experiments to quantify the reduction of energy use and CO2 emissions. As a result of cooling experiments, it was found that the aluminum powder mold had an energy reduction effect of 14.3% against the PCM mold that had been produced only with paraffin wax, and CO2 reduction effect of more than 50% against the conventional mold.

There has been an increase in demand for free-form building through the development of advanced technologies, and the fourth industrial revolution has become a worldwide trend, thereby changing the construction industry. In particular, in the case of the free-form architecture sector, development of 3D printing technologies has been ongoing for construction automation. According to such trends, this study develops an FCP production equipment using 3D printing technologies. The FCP production equipment in this study is made up of mould equipment and 3D printer. It is different from existing 3D printing technologies so in this study 3D concrete extrusion nozzle must be developed for producing FCP. Basic design suitable to such requirements is proposed.  Applicability of the proposed design is checked and the nozzle form is concretized to draft the final drawing. In this study, slit-type opening and closing device for accurate extrusion stoppage of concrete and screw-type nozzle for adjusting pressure and extrusion speed were applied for the nozzle. This is expected to be innovative technology for the FCP production sector.

This article provides a novel insight into specific properties of flat folded sheets transformed elastically into building roof shells. Elastic twist transformations of the sheets resulting from the arrangement of the sheets on two skew roof directrices cause changes in the geometric and mechanical sheet properties of the roof shell sheeting composed of these sheets. Regular smooth-ruled surfaces and their characteristic lines are used in the analysis of changes in the geometric properties. In the analysis of the mechanical changes, the constitutive relations and complex state of stresses are considered. The analysis is carried out on the basis of the results of the experimental tests and FEM computer simulations. They have led to the development of such a method of shaping of the effectively transformed folded covers that ensures the initial effort of each shell fold to be the smallest possible.

This article is an insight into interdisciplinary topics in the field of civil engineering, morphology, architecture, mechanics, and computer programming. A novel method for shaping unconventional complex roofs in which regular folded units transformed into various shells are used as a complex substitute material is proposed. The original method’s algorithm for building systems of planes defining diversified polyhedral networks in the three-dimensional space by means of division coefficients of the subsequently determined vertices is presented. The algorithm is based on the proportions between the lengths of the edges of the reference network, the location and shape of the ruled shell units included in the designed complex roof structure, so it is intuitive. The shell units are made up of nominally flat folded sheets transformed effectively into shell forms whose static-strength properties are controlled by geometric quantities characteristic of ruled surfaces. The presented original approach to the shaping of the shell roof structures determining specific complex building forms allows us to go beyond the limitations related to the orthotropic structure of the folded roof sheeting and the shape transformations.

The article presents author’s propositions for shaping free forms of buildings sensitive to harmonious incorporation into built or natural environments. Complex folded structures of buildings roofed with regular shell structures are regarded as the most useful in creative shaping the free forms that can easily adapt to various expected environmental conditions. Three more and more sophisticated methods are proposed for creating variously conditioned free form structures. The first method allows the possibility of combining many single free forms into one structure and leaves the designer full freedom in shaping regular or irregular structures. The second, more sophisticated method introduces additional rules supporting the designer’s spatial reasoning and intuition in imposing regularity of the shapes of the building structure and its roof shell structure. The third, most sophisticated method introduces additional conditions allowing the optimization of the regular shapes and arrangement of complete shell roof segments on the basis of an arbitrary reference surface and a finite number of straight lines normal to the surface. This original, interdisciplinary study offers new insight into, and knowledge of, unconventional methods for the creative shaping of innovative free forms, where great possibility and significant restrictions result from geometrical and mechanical properties of the materials used. Solving a number of issues in the field of civil engineering, descriptive geometry and architecture is crucial in the process of creating these structures.