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The purpose of this study is to assess the influence of Al and Ag addition on thermal, mechanical and shape memory properties of Cu-Al-Ag alloy.

The material is synthesized in a controlled atmosphere to minimize the reaction of alloying elements with the atmosphere. Cast samples were homogenized, then subjected to hot rolling and further betatized, followed by step quenching. Eight samples were chosen for study among which first four samples varied in Al content, and the next set of four samples varied in Ag composition.

The testing yielded a result that the increase in binary alloying element decreased transformation temperature range but increased entropy and elastic energy values. It also improved the shape memory effect and mechanical properties (UTS and hardness). An increase in ternary alloying element increased transformation temperature range, entropy and elastic energy values. The shape memory effect and mechanical properties are enhanced by the increase in ternary alloying element. The study revealed that compositional variation of Al should be limited to a range of 8 to 14 Wt.% and Ag from 2 to 8 Wt.%. Microstructural and diffraction studies identified the ß’1 martensite as a desirable phase for enhancing shape memory properties.

Numerous studies have been made in exploring the transformation temperature and phase formation for similar Cu-Al-Ag shape memory alloys, but their influence on shape memory effect was not extensively studied. In the present work, the influence of Al and Ag content on shape memory characteristics is carried out to increase the design choice for engineering applications of shape memory alloy. These materials exhibit mechanical and shape memory properties within operating ranges similar to other copper-based shape memory alloys.

The purpose of this paper is to present short characteristics of shape memory alloys (SMA) and shape memory polymers (SMP) and some examples of application of these materials in industrial sealing technology.

In this paper, short characteristic of shape memory materials and design examples of applying them in industrial sealing technology such as: tube coupling in hydraulic systems, flanged pipe connections, lip radial seal, mechanical face seal, soft gland packing, magnetic fluid seal, and in bearing seal system for drill bit, are given.

The paper provides information about innovative fluid seal designs based on particular properties of the shape memory materials, applied in stationary joints, and rotary equipments. These new solutions provide often to simplify seal design, their miniaturization, increase of tightness, and reduction of operating costs.

This paper offers some new fluid seal designs based on the shape memory materials and their practical application in industrial sealing technology.

Shape memory polymers (SMPs) respond with a change in their shape against a specific stimulus by memorizing their original shape and are reformed after deformation most often by changing the temperature of the surrounding without additional mechanical efforts. In the coming years, these polymers indeed will be in limelight to manufacture textile materials which will retain their shape even after prolonged use under disturbed conditions. This study aims at defining shape memory materials and polymers as well as their technological characteristics and also highlights application in various fields of textiles.

The methodology used to explain these SMPs have been carried out starting with the discussion on their properties, their physical nature, types, viz., shape memory alloys (SMAs), shape memory ceramics, shape memory hybrid, magnetic shape memory alloy, shape memory composites, shape memory gels and SMP along with properties of each type. Other related details of these polymers, such as their advantages, structure and mechanism, shape memory functionality, thermally responsive SMPs and applications, have been detailed.

It has been observed that the SMPs are very important in the fields of wet and melt-spun fibers to offer novel and functional properties, cotton and wool fabric finishing, to produce SMP films, foams and laminated textiles, water vapor permeable and breathable SMP films, etc.

The field of SMPs is new, and very limited information is available to enable their smooth production and handling.

Describes a range of cryogenic tube and pipe couplings which make use of shape memory alloy technology in order to form permanent metal‐to‐metal seals on aircraft. Compares and contrasts their costs and method of installation with alternative swaged systems.

This paper aims to examine customized NiTi jewels with functional properties fabricated through four-dimensional (4D)-printing.

Two opened rings are fabricated through selective laser melting starting from 55.2Ni-Ti (wt.%) micrometric powder. After the additive process the two rings present the one-way shape memory effect (OWSME). A specific training is accomplished on one of the two printed rings to promote the two-way shape memory effect (TWSME). Both the samples, namely, the rings, respectively, presenting the OWSME and TWSME property, follow a series of post-processing routes to improve the surface finish. Furthermore, a thermal treatment at high temperature is used to create a thin colored oxide layer on the sample surface.

Results show that the change of shape owing to the OWSME and TWSME properties allows the customized 4D-printed rings to be adaptable to environmental changes such as load and temperature variations. This adaptability improves comfort and fit of the jewels.

To the best of the authors’ knowledge, in this work, first cases of additively manufactured NiTi jewels are reported to propose innovative solutions in the design and processing industry of jewels.

Variable stiffness structure can significantly improve the interactive capabilities of grippers. Shape memory alloys have become a popular option for materials with variable stiffness structures. However, its variable stiffness range is limited by its stiffness in two phases. The purpose of this paper is to enhance the manipulation capabilities of tendon-driven flexible grippers by designing a wide-range variable stiffness structure.

Constitutive models of shape memory alloy and mechanical models are used to analyze the performance of the variable stiffness structure. A separated solution was used to combine the tendon-driven gripper and the variable stiffness structure. The feed-forward control algorithm is used to enhance the control stability of the variable stiffness structure.

The stiffness variable capability of the proposed variable stiffness structure is verified by experiments. The stability of the feedback control algorithm was verified by sinusoidal tracking experiments. The variable stiffness range of 8.41 times of the flexible gripper was tested experimentally. The interaction capability of the variable stiffness flexible gripper is verified by the object grasping experiments.

A new wide-range variable stiffness structure is proposed and validated. The new variable stiffness structure has a larger range of stiffness variation and better control stability. The new flexible structure can be applied to conventional grippers to help them gain stiffness variable capability and improve their interaction ability.

The purpose of this paper is to understand the recovery mechanism of poly(trimethylene terephthalate) (PTT) shape memory fabrics.

Tests were designed to study the effects of force, temperature and their combinations on the fabrics' crease recoveries. In the test a cantilever device and an ironing force which simulated people ironing their clothes were used, respectively.

Temperature was found to have little effect on the recovery of both the warp and filling of the fabrics. Crease recoveries did not improve significantly when the temperature was increased to above the polymer's glass transition. However, forces, applied in primarily compressive and tensile modes to simulate ironing and hand stroking actions, were found to be very effective in the fabrics' crease recoveries. Recoveries were 81‐87 per cent even when the applied force was very small, at 5 N/cm². When forces were applied at elevated temperatures, just below and above the polymer's glass transition, there were no significant improvements in crease recoveries. Therefore, force was the main factor in PTT shape memory fabrics' recovery mechanism for the fabrics to return to their initial shapes.

The results suggest that PTT shape memory fabric has excellent shape recoverability and easy care property and it has large application potentiality.

This study aims to present an architectural application of 4D-printed climate-adaptive kinetic architecture and parametric façade design.

This work investigates experimental prototyping of a reversibly self-shaping façade, by integrating the parametric design approach, smart material and 4D-printing techniques. Thermo-responsive building skin modules of two-way shape memory composite (TWSMC) was designed and fabricated, combining the shape memory alloy fibers (SMFs) and 3D-printed shape memory polymer matrices (SMPMs). For geometry design, deformation of the TWSMC was simulated with a dimension-reduced mathematical model, and an optimal arrangement of three different types of TWSMC modules were designed and fabricated into a physical scale model.

Model-based experiments show robust workability and formal reversibility of the developed façade. Potential utility of this module for adaptive building design and construction is discussed based on the results. Findings help better understand the shape memory phenomena and presented design-inclusive technology will benefit architectural communities of smart climate-adaptive building.

Two-way reversibility of 4D-printed composites is a topic of active research in material science but has not been clearly addressed in the practical context of architectural design, due to technical barriers. This research is the first architectural presentation of the whole design procedure, simulation and fabrication of the 4D-printed and parametrically movable façade.

Additive manufacturing has rapidly developed in terms of technology and its application in various types of industries. With this rapid development, there has been significant research in the area of materials. This has led to the invention of Smart Materials (SMs). The 4D printing is basically 3D printing of these SMs. This paper aims to focus on novel materials and their useful application in various industries using the technology of 4D printing.

Research studies in 4D printing have increased since the time when this idea was first introduced in the year 2013. The present research study will deeply focus on the introduction to 4D printing, types of SMs and its application based on the various types of stimulus. The application of each type of SM has been explained along with its functioning with respect to the stimulus.

SMs have multiple functional applications pertaining to appropriate industries. The 4D printed parts have a distinctive capability to change its shape and self-assembly to carry out a specific function according to the requirement. Afterward, the fabricated part can recover to its 3D printed “memorized” shape once it is triggered by the stimulus.

The present study highlights the various capabilities of SMs, which is used as a raw material in 4D printing.