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A collision-free path planning method is proposed based on learning from demonstration (LfD) to address the challenges of cumbersome manual teaching operations caused by complex action of yarn storage, variable mechanism positions, and limited workspace in preform weaving. First, by utilizing extreme learning machines (ELM) to autonomously learn the teaching data of yarn storage, the mapping relationship between the starting and ending points and the teaching path points is constructed to obtain the imitation path with similar storage actions under the starting and ending points of the new task. Second, an improved rapidly expanding random trees (IRRT) method with adaptive direction and step size is proposed to expand path points with high quality. Finally, taking the spatical guidance point of imitation path as the target direction of IRRT, the expansion direction is biased toward the imitation path to obtain a collision-free path that meets the action yarn storage. The results of different yarn storage examples show that the ELM-IRRT method can plan the yarn storage path within 2s–5s when the position of the mechanism changes in narrow spaces, avoiding tedious manual operations that program the robot movements, which is feasible and effective. [ABSTRACT FROM AUTHOR]

Nowadays, concrete canvas is used in various fields of civil engineering and architecture. Therefore, improving the mechanical properties of this product is important in order to increase the scope of its using. In this study, the effect of yarn and weave of 3-D spacer fabric was investigated on flexural and tensile strengths of concrete canvas. For this purpose, four samples of 3-D spacer fabrics with different yarns and weaves were prepared and the cement was injected into these samples. After hydration of concrete canvas, the initial cracking stress, final stress and tensile strength were obtained. The results showed that the number of spacer yarns has a significant effect on the amount of initial cracking stress, and the final stress of flexural strength is also increased almost with increasing the initial cracking stress. The results also showed that the type of yarn used in the 3-D spacer fabric has a significant effect on the tensile strength. The tensile strength of concrete canvas is increased with increasing the capillary ability of the samples, due to the better hydration of concrete. [ABSTRACT FROM AUTHOR]

Folk heritage is one of the types of heritage arts, especially the symbol, as it is one of the most important features of folk art, and heritage is that heritage that carries the thought and culture of society in previous eras and must be preserved, understood and formulated with acontemporary artistic vision. Contemporary technical dialogue adds a modern artistic vision to business. The symbol is one of the most important features of folk art, so we rarely find a popular artwork except that the symbol in it relates to a topic in the life of the popular artist, his customs, traditions and society so the researcher believes that it requires the practice of experimentation to combine the aesthetics of textile and added fabric using the remaining fabrics and threads in order to reveal the relationships and the artistic and aesthetic capabilities of that common relationship. Except by using experimentation in art that presents different unfamiliar alternatives and solutions to reach aspects and solutions of a different aesthetic nature The current research seeks to understand and deepen the folk symbols and formulate them in innovative ways to add a kind of renewal not only in the form of the woven, but we see it in the philosophical content of the textile work, where we see it with a contemporary plastic vision based on the spirit of heritage and does not stop at the limit of imitation and repetition, but seeks to find a different template that departs from Borders of the Ordinary seeks to adapt the thought of folklore into contemporary textiles that combine texture and added texture.

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In motorcycle dynamics, great importance is attributed to the study of the weave and wobble vibration modes and, in particular, to the effects of the flexibility of structural components on their stability. Therefore, appropriate motorcycle models for studying weave and wobble should include flexible elements for describing the flexural behavior of components such as the main frame, front assembly, and rear swingarm. Different approaches are possible for modeling flexibilities: the most common among them are the lumped stiffness and the flexible multibody approaches. While the latter certainly provides higher accuracy, the former has advantages in terms of computational load, but, above all, it makes it easier to understand in the design phase how technical parameters, such as torsional and bending stiffness of a given structural component, can influence the stability of weave and wobble. The accuracy of lumped stiffness models strongly depends on parameter identification. In this study, a general method is proposed to determine appropriate lumped stiffness parameters for any given motorcycle component. The proposed method is tested and validated by comparing the weave and wobble modal behavior with the results of flexible multibody analysis. The lumped stiffness model is then adopted to carry out a sensitivity analysis aimed at identifying the effects on the weave and wobble stability of the torsional and bending stiffness of specific structural components of the motorcycle to optimize their design. [ABSTRACT FROM AUTHOR]

Fe3Al combines with steel to form bimetallic metal can benefit from steel's mechanical strength and make full use of Fe3Al's excellent performance under high temperatures. However, due to the poor fluidity and wettability of liquid Fe3Al to steel, the cladding prepared by traditional linear welding is not available to industrial sector. Hence, to optimize preparation, an arc deposition procedure based on a weaving path is proposed. Fe3Al cladding was prepared on the steel with weaving and linear paths by arc deposition technology, respectively, and the characteristics of the cladding were compared in terms of formability, surface feature and microstructure. The results demonstrated that the cladding prepared by weave arc deposition had better formability, lower dilution rates and fewer defects than that by the line one. Compared with the image captured by high-speed camera, the substantial difference was attributed to the higher molten pool velocities, which led to a smaller volume of molten pool in weave process. Under this circumstance, the arc force was conducive to the spread of liquid metal, forming a relatively small contact angle (< 45°). The finite element analysis revealed that the temperature distribution and thermal cycles resulted in finer grains in the weave process; furthermore, the weave process produced less residual stress, causing an increment of 153% in bonding strength between the cladding and the steel, compared to linear sample. Overall, the weave arc deposition technology is capable of molding Fe3Al layers efficiently and offers a good prospect for applications. [ABSTRACT FROM AUTHOR]