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Industrial Applications
Published in Vlado Valković, Low Energy Particle Accelerator-Based Technologies and Their Applications, 2022
By now, it is established that replacing steel with X-ray cured carbon composites can reduce car energy consumption by 50%. Carbon–fiber-reinforced composites were cured in molds using X-rays derived from a high-energy, high-current EB. X-rays could penetrate the mold walls as well as the fiber reinforcements and polymerize a matrix system. Matrix materials made from modified epoxy-acrylates were tailored to suitably low viscosity so that fiber wetting and adhesion could be attained. Techniques similar to vacuum-assisted resin transfer molding (VARTM) and conventional vacuum bagging of wet lay-ups were used. Inexpensive reinforced polyester molds were used to fabricate vehicle fenders. Moderately low-dose X-ray exposure was sufficient to attain functional properties, such as resistance to heat distortion at temperatures as high as 180°C. The matrix system contained an impact additive that imparted toughness to the cured articles. “Class A” high gloss surfaces were achieved. Thermo-analytical techniques were used on small-sized samples of X-ray-cured matrix materials to facilitate the selection of a system for use in making prototypes of vehicle components. X-rays-penetrated metal pieces that were placed within layers of carbon-fiber twill, which were cured and bonded into a structure that could be mechanically attached without concern over fracturing the composite. X-ray curing is a low-temperature process that eliminates residual internal stresses which are imparted by conventional thermo-chemical curing processes (Herer et al. 2009).
Disc Structure and Function
Published in Peter Ghosh, The Biology of the Intervertebral Disc, 2019
It has been suggested that the elastic fibers provide protection against the potentially damaging effects of sudden loading on the annular fibers.86 Materials have been formulated for engineering applications in which a few fibers with high strength but low stiffness are incorporated into a conventional fiber-reinforced composite material. Incorporation of these low-stiffness fibers confers extra resilience on the material.108 Since elastic fibers are much less stiff than collagen fibrils, they may have a similar effect on the properties of annular fibers.
Numerical analysis of support structures on an adhesive dental bridge
Published in J. Belinha, R.M. Natal Jorge, J.C. Reis Campos, Mário A.P. Vaz, João Manuel, R.S. Tavares, Biodental Engineering V, 2019
G.A.R. Caldas, J. Belinha, R.M. Natal Jorge
As an alternative to the Maryland bridge appeared the direct fibre reinforced composite (FRC) bridge, technique that can improve the adhesion of the wing of the bridge to the abutment. In this way, the stresses applied at the interface between the bridge and the abutment tooth can be reduced (Li, Swain, Li, & Steven, 2005) (Vallittu & Sevelius, 2000). Many researchers study FRC bridges trying to develop an optimized design, which includes thickness, position and orientation of the fibres. Therefore, the fibres directions have to be aligned with those of the maximum principal stresses. Hence, it is necessary to discover the locations of higher stresses and directions of maximum principal stresses. Once high tensile stresses were found in the bottom of the pontic and in the connectors that link the pontic to the abutment teeth, it was concluded that fibres should be placed in the bottom of the pontic tooth extending to the connectors. Consequently, the optimized design is a U-shape substructure. The optimized design can improve fracture resistance of FPDs by reducing some of the failure-initiating stresses (Nakamura, Ohyama, Waki, & Kinuta, 2005) (Shi & Fok, 2009).
Adhesion of individually formed fiber post adhesively luted with flowable short fiber composite
Published in Biomaterial Investigations in Dentistry, 2023
Anton O. Suni, Lippo V. J. Lassila, Jarno K. Tuokko, Sufyan Garoushi, Pekka K. Vallittu
In recent decades, adhesive dentistry has grown quickly. Since the use of modern dental materials produces results that are superior to those of conventional ones, a number of novel and creative treatments have replaced traditional treatment approaches. The development of fiber-reinforced composite (FRC) posts as a reliable substitute for prefabricated metal posts marked a turning point in the field of dentistry [1,2]. Their modulus of elasticity being similar to dentin and their ability to bond to luting cement and tooth structure have been suggested to reduce the likelihood of root fractures most commonly associated with endodontically treated teeth (ETT) restored with metal posts [3]. This coupled with their superior esthetics and easy retrieval adds to their many advantages, making fiber-reinforced posts the material of choice in routine dental practice.
Microencapsulation of reactive isocyanates for application in self-healing materials: a review
Published in Journal of Microencapsulation, 2021
Amanda N. B. Santos, Demetrio J. dos Santos, Danilo J. Carastan
The development of self-healing materials was inspired by natural biological systems which present a healing response after being damaged without the need of external intervention (Yuan et al.2008, Blaiszik et al.2010, Yang and Urban 2013). These smart materials emerge as a promise to increase durability and reliability of polymeric materials used in structural applications, such as in fiber-reinforced composites. Such polymers are often thermosets with a brittle behaviour and nano and microcracks appear inside them in long term applications. These flaws are hardly detectable and often evolve to material failure, increasing maintenance costs and restricting their use (Zhu et al.2015).
A comparative finite element simulation of locking compression plate materials for tibial fracture treatment
Published in Computer Methods in Biomechanics and Biomedical Engineering, 2021
Sami Beirami, Mohammad Nikkhoo, Kamran Hassani, Alireza Karimi
The biomechanical complications may arise after LCP operations, especially the mechanical ones related to the stresses and strains in the LCP system, cannot be investigated experimentally. Numerical techniques, such as finite element (FE), due to their acceptance in orthopedics research can effectively be used to calculate the stresses and strains in the plate and screws under various loading and boundary conditions (Duda et al. 2001; Krishna et al. 2008). Various biomechanical studies have been done to investigate the stability and functionality of joints and bone construct (Bresina and Tepic 1995; Blecha et al. 2005; Benli et al. 2008). A FE analysis of bone plates of prophylactic internal fixation of the radial osteocutaneous was conducted using the sheep tibia model (Avery et al. 2013). Although most studies so far have been focused on the type of the LCP, whether internal (Niemeyer and Sudkamp 2006; Saidpour 2006; Oh et al. 2010) or external (Liu et al. 2017; Ma et al. 2017; Matsuura et al. 2017), there is a lack of knowledge on the role of the material properties of the LCP system in controlling the stresses and strains in the implant-bone system. Fiber-reinforced composite materials showed to have relatively high strength and flexibility compared to the metals (Davidson 1987; Skinner 1988). Hence, a more uniform load transfer, less stress shielding, and less bone loss occur in them (Magee et al. 1988; Keaveny and Bartel 1995). Carbon fibers embedded in polyetheretherketone (PEEK) polymer matrices have good biocompatibility (Wenz et al. 1990) and strength (Akay and Aslan 1996; Puleo and Nanci 1999), which make them a suitable choice for implant design. In addition, owing to their excellent strength under friction or shear loads they can minimize the friction at the interface of the tibia and plate/screws (Ryoo and Kim 2001; Yoon et al. 2013).