Smart Materials in Additive Manufacturing, volume 1: 4D Printing Principles and Fabrication

Smart Materials in Additive Manufacturing, Volume 1 provides readers with an overview of the current smart materials widely in use and the techniques for additively manufacturing them

Smart Materials in Additive Manufacturing, volume 2: 4D Printing Mechanics, Modeling, and Advanced Engineering Applications

The book demonstrates 4D printing techniques for electro-induced shape memory polymers, pneumatic soft actuators, textiles, and more

Design and Fabrication of Microarchitected Thermoelectric Generators: Prospects and Challenges

Solid‐state devices called thermoelectric generators (TEGs) can convert waste heat from production into electrical power. For emerging devices like thermally integrated energy‐autonomous devices, medicinal equipment, and Internet of Things, μ‐TEGs are essential because they can produce power even from minor temperature gradients. A review of the history and state‐of‐the‐art of μ‐TEGs is provided in this article. In addition, it concentrates on highly effective approaches for achieving high‐performance miniature vertical thermoelectric (TE) devices. Design and optimizing methodologies for vertical μ‐TEGs are also investigated since their output power, efficiency, and integrity are critical to the architecture. Improving electrical and mechanical performance may be achieved via optimization methods, including multiobjective and finite‐dimensional optimization in three dimensions (3D). Additionally, the idea and latest advancements of employing the 3D microadditive manufacturing (micro‐AM) technique for producing μ‐TEGs are discussed, along with their advantages and disadvantages. The concept of “microarchitected TEGs” as opposed to “μ‐TEGs” is provided by the new paradigm of digital AM and architected material concept, which also broadens the scope of material adaptability and innovative structural design. The difficulties experienced are summed up when increasing the output power of μ‐TEG and the prediction of future trends is the final step

4D printing modeling using ABAQUS: A guide for beginners

printing. modeling. using. ABAQUS: A. guide. for. beginners. Hamid Reza Jarraha, Ali Zolfagharianb, Bernard Rolfeb, and Mahdi Bodaghia aDepartment of Engineering, School of Science and Technology, Nottingham Trent University, ..

Fluid–structure interaction (FSI) simulation for studying the impact of atherosclerosis on hemodynamics, arterial tissue remodeling, and initiation risk of intracranial aneurysms

The biomechanical and hemodynamic effects of atherosclerosis on the initiation of intracranial aneurysms (IA) are not yet clearly discovered. Also, studies for the observation of hemodynamic variation due to atherosclerotic stenosis and its impact on arterial remodeling and aneurysm genesis remain a controversial field of vascular engineering. The majority of studies performed are relevant to computational fluid dynamic (CFD) simulations. CFD studies are limited in consideration of blood and arterial tissue interactions. In this work, the interaction of the blood and vessel tissue because of atherosclerotic occlusions is studied by developing a fluid and structure interaction (FSI) analysis for the first time. The FSI presents a semi-realistic simulation environment to observe how the blood and vessels' structural interactions can increase the accuracy of the biomechanical study results. In the first step, many different intracranial vessels are modeled for an investigation of the biomechanical and hemodynamic effects of atherosclerosis in arterial tissue remodeling. Three physiological conditions of an intact artery, the artery with intracranial atherosclerosis (ICAS), and an atherosclerotic aneurysm (ACA) are employed in the models with required assumptions. Finally, the obtained outputs are studied with comparative and statistical analyses according to the intact model in a normal physiological condition. The results show that existing occlusions in the cross-sectional area of the arteries play a determinative role in changing the hemodynamic behavior of the arterial segments. The undesirable variations in blood velocity and pressure throughout the vessels increase the risk of arterial tissue remodeling and aneurysm formation

4D Metamaterials with Zero Poisson's Ratio, Shape Recovery, and Energy Absorption Features

This article introduces novel 3D zero Poisson's ratio (ZPR) metamaterials for reversible energy absorption applications fabricated by 4D printing technology. The designs are introduced based on piecemeal energy absorption (PEA) and conventional energy absorption (CEA) approaches. Topologically, the design of the 3D metamaterials is founded on star-shaped unit cells herein. To achieve the PEA behavior, horizontal bars are merged into the parent star-shaped unit cell. This leads to introducing multistiffness unit cells (controllable unit-cell densifications) to provide stability and different peak force levels during compression. For further evaluation, finite element analysis (FEA) is employed. To illustrate the design functions during physical operation and validate the FEA, lattice-based metamaterials are fabricated from resin with a shape recovery property by an SLA 3D printer and tested mechanically. Close coincidence is observed between the FEA and the experiments, showing the accuracy of the modeling. A thermal test, via a heating–cooling process, is also carried out to display the shape recovery capability of metamaterials where plastic deformations are fully released, and samples get back to their original shapes. Finally, the newly proposed ZPRs are compared with conventional 3D reentrant metamaterials in terms of energy absorption capacity, demonstrating their considerable mechanical performances

4D printing of shape memory polymer composites: A review on fabrication techniques, applications, and future perspectives

4D printing of shape memory polymer composites: A review on fabrication techniques, applications, and future perspective

Vitrimer chemistry for 4D printing formulation

Vitrimerization is one of the new methods under development to convert polymer wastes into high-value compounds. The chemistry of vitrimers is such that the presence of dynamic chemical bonds changes the permanent covalent bonds into covalent adaptable networks, which are reversible. This allows for recycling and reprocessing of polymers by maintaining their initial properties after several cycles, which is included in the preparation of polymer resins to convert polymer waste into materials that can be formulated for three-dimensional (3D) printing resins. Four-dimensional (4D) printing has also been recently introduced as sustainable 3D printing of responsive polymers with dynamic applications, such as soft robotics, medicine, and medicals. Therefore, the synthesis of polymers with dynamic chemistry based on vitrimers can add unique properties such as shape memory, shape recovery, self-healing, and flexibility to the 3D printed products. Vitrimerization chemistry could contribute to polymer waste by producing 4D-printed resins. This article presents the vitrimerization chemistry used in different polymers to produce 4D printing resins with the mentioned capabilities and lists their recipes for the preparation of formulations used in 4D printing so that the researchers can use them in a practical way to possibly achieve simultaneous shape-programmable, self-healing, and recyclable features in printed structures

Biopolymeric sustainable materials and their emerging applications

Advancements in polymer science and engineering have helped the scientific community to shift its attention towards the use of environmentally benign materials for reducing the environmental impact of conventional synthetic plastics. Biopolymers are environmentally benign, chemically versatile, sustainable, biocompatible, biodegradable, inherently functional, and ecofriendly materials that exhibit tremendous potential for a wide range of applications including food, electronics, agriculture, textile, biomedical, and cosmetics. This review also inspires the researchers toward more consumption of biopolymer-based composite materials as an alternative to synthetic composite materials. Herein, an overview of the latest knowledge of different natural- and synthetic-based biodegradable polymers and their fiber-reinforced composites is presented. The review discusses different degradation mechanisms of biopolymer-based composites as well as their sustainability aspects. This review also elucidates current challenges, future opportunities, and emerging applications of biopolymeric sustainable composites in numerous engineering fields. Finally, this review proposes biopolymeric sustainable materials as a propitious solution to the contemporary environmental crisis

4D printing: Technological developments in robotics applications

The idea of four-dimensional (4D) printing is the formation of intricate stimuli-responsive 3D architectures that transform into different forms and shapes upon exposure to environmental stimuli. 4D printing (4DP) of smart/intelligent materials is a promising and novel approach to generate intricate structures for biomedical, food, electronics, textile, and agricultural fields. Nowadays, soft robotics is a growing research field focusing on developing micro/nanoscale 4D-printed robots using intelligent materials. Herein, recent advancements in 4DP of soft robotics, actuators, and grippers are summarized. This review also highlights some recent developments in novel robotics technologies and materials including multi-material printing, electro-, and magneto-active soft materials (MASMs), and metamaterials. It also sheds light on different modeling mechanisms including numerical models and machine learning (ML) models for fabricating highly precise and efficient micro/macro-scaled robots. The applications of shape-memory polymers (SMPs), hydrogels, and liquid crystal elastomers (LCEs)-based 4D-printed soft and intelligent robots in different engineering fields are highlighted. Lastly, this review incorporates current challenges which are hindering the actual utilization of 4D-printed soft robotics and their possible remedies