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To solve the reinforcement congestion, mechanical anchorage is increasingly popular in use instead of conventional hook rebar. However, the bond performance between the rebar and concrete and the range of stress transfer between the two are still not well understood. The purpose of this study is to study the bond performance and failure mechanisms between reinforcement and concrete around an anchorage zone in a structural element.

In this study, simulations were carried out by 3D RBSM (Rigid Body Spring Model). This approach divided a problem of interest into elements, namely concrete and steel elements. And to simulate the failure of anchorage of RC, the steel element size is set according to the geometry complexity of the reinforcing bar. By using this method, two simulation cases of anchorage failure were carried out.

This paper shows that simulations demonstrated good agreement with experimental data in terms of anchorage capacity, crack pattern, and failure mode. This indicates that RBSM analysis can simulate the failure behavior governed by complex cracks.

This paper indicates the analytical approach to investigate the anchorage performance of RC.

The purpose of this paper is to focus on tracheal stent production with the aim of investigating the available devices and improving their performances. The biomedical field is a continuously growing area of the market always in search of the most innovative and competitive solutions for healthcare. Beside the actual critical period of the world economy, it shows continuous improvements in research and innovation.

Within a market analysis and the collaboration between engineering and biomedical research fields, it was outlined a new product concept able to satisfy the patient’s and physician’s requirements with the focus on the enhancement of the stent anchorage. As a result, the concept of a custom- or tailor-made stent was identified as a potential solution. Moreover, additive technologies were identified as the economically sustainable processes for manufacturing these innovative stents. In the present paper, different types of stents were derived from the proposed concept, they were designed, manufactured and their anchorage capability was tested. In particular, the procedures adopted for their design are described and discussed. Moreover, silicone fused deposition modelling was adopted and two types of deposition method, namely, layer-by-layer and continuous, were used to manufacture the devices identifying their pro, cons and limits. Finally, the stents were tested against migration and results were compared with one of the most widely used today.

The results show how additive manufacturing allowed to manufacture more efficient and migration resistant stents.

It is expected that this new stent design will reduce the risk of complications in stenting, as granulation, thanks to a more uniform stress distribution on the trachea tissues. These improved characteristics will allow to enhance the quality of both the product and the patient’s healthcare.

Most existing studies are confined to model beam tests, which cannot reflect the actual strengthening effects provided by prestressed carbon-fiber-reinforced polymer (CFRP) plates to existing bridges. Hence, the actual capacity for strengthening existing bridges with prestressed CFRP plates is becoming an important concern for researchers. The paper aims to discuss these issues.

Static load tests of in-service prestressed concrete hollow slabs before and after strengthening are conducted. Based on the results of the tests, the failure characteristics, failure mechanism and bending performance of the slabs are compared and analyzed. Nonlinear finite element method is also used to calculate the flexural strength of the strengthened beams prestressed with CFRP plates.

Test results show that prestressed CFRP plate strengthening technology changes the failure mode of hollow slabs, delays the development of deflection and cracks, raises cracking and ultimate load-carrying capacity and remarkably improves mechanical behavior of the slab. In addition, the nonlinear finite element analyses are in good agreement with the test results.

Strengthening with prestressed CFRP plates has greater advantages compared to traditional CFRP plate strengthening technology and improves active material utilization. The presented finite element method can be applied in the flexural response calculations of strengthened beams prestressed with CFRP plates. The research results provide technical basis for maintenance and reinforcement design of existing bridges.

The study aims to review the literatures on the effect of fiber length on the mechanical response of natural fiber composite will help the researchers to know about the perspective of the various natural fibers in making of composite concerning fiber length. The review summarized the work of the other researchers, thereby unambiguously précised suitability of a specific natural fiber for a matrix in use. Thus, one can identify the use of the same fibers–matrix combination to obtain composites with different properties with the control of fiber/matrix interface.

The review work proposes a new kind of diagrammatic representation that expresses the influence of fiber length. This work has not been explored before in this specific format. The chronology of work may help to select natural fibers for use in composites for a specific matrix.

The length of the fiber perception in terms of “critical” length decides the need for pre-treatment process of natural fiber to improve shear stress at the interface for various matrices.

The current review paper attempts to shed light on the association between the fiber length of natural fiber and the mechanical response of natural fiber composite. Moreover, it probes the concepts of critical fiber length as a persuadable factor.

The effects of failure mode and strain conditions of CFRP, concrete and stirrups on the shear capacity of reinforced beams bonded by geopolymer and epoxy are studied. In addition, a prediction model of the ultimate bearing capacity of CFRP-shear-strengthened beams is proposed, which considers adhesive performance parameters adhesive performance parameter ßE and FRP width parameter ßw.

This paper presents an experimental study on ultimate bearing capacity of CFRP-shear-strengthened pre-cracked beams with geopolymer and epoxy resin, which considers parameters such as impregnated adhesives types and CFRP-strengthened scheme.

The failure modes of CFRP-strengthened beams bonded by geopolymer are the combination of the CFRP-concrete interface substrate failure and fracture failure of CFRP, and that of epoxy is the local substrate failures with small area. The ultimate load of CFRP-strengthened beams is directly affected by the failure modes. The ultimate bearing capacity of CFRP-strengthened beams with geopolymer is 91.4% of that of epoxy resin. Compared with ultimate bearing capacity of CFRP-strengthened beams with U-shaped, that of complete-wrapping increases by 2.5%. Moreover, the stirrup peak strain is reduced by more than 30% in CFRP-strengthened beams bonded with geopolymer and epoxy resin in comparison with the unstrengthened beam. The existing prediction model cannot accurately predict the CFRP shear capacity contribution of strengthened beams with different CFRP-strengthened schemes and adhesive properties. The estimated results are much lower than the test data, and the deviation is much larger than 20%.

Geopolymer alternative to epoxy as an adhesive is feasible and effective for CFRP reinforcement. Furthermore, the accuracy is improved by introducing parameters about adhesive properties based on the existing prediction model. The estimated results are in excellent agreement with the test data, and the deviation is controlled within −12.80%, and the model is suitable for predicting the shear capacity of FRP-strengthened beams with ßf = 90° in shear capacity database.

Spray-applied fire-resistive materials (SFRMs) are the most commonly used passive fire protection for steel structure in the USA. However, they are often called into question because of their poor durability (cohesive and adhesive) performance. Being an inherently brittle material with low tensile strength, SFRM tends to dislodge and delaminate under extreme loads and service loads. Such loss of fire protection greatly endangers the steel structures, especially under multi-hazards like post-earthquake/impact fires. The purpose of this paper is to introduce a new technology of a ductile cement-based SFRM, namely, spray-applied fire-resistive engineered cementitious composite (SFR-ECC) that overcomes the aforementioned problems and contributes toward enhanced fire safety of steel structures.

SFR-ECC has been developed as a durable alternative to conventional SFRM by adopting engineered cementitious composite (ECC) technology in the material design process. Various experimental studies have also been conducted to fully evaluate the performance of SFR-ECC.

It is found that SFR-ECC possesses much better durability performance under both static and high-rate loading compared to conventional SFRMs. With many unique properties, applications of SFR-ECC for pre-fabrication of passive fire protection are also found to be feasible.

This paper is a comprehensive introduction of the newly developed SFR-ECC. It summarizes the key properties of SFR-ECC and provides a useful guideline for further investigation and field application of SFR-ECC.

A comparative study on methods for cleaning copper‐clad boards with abrasive slurries is presented. A number of methods are analysed in detail; the conclusions indicate that brush scrubbing with abrasive slurries offers a wider processing window, whereas jet scrubbing is less ‘forgiving’ for the small/medium‐sized manufacturers where more handling of the material is necessary due to reduced automation. For the larger high volume manufacturers of printed circuit boards with higher levels of automation and tighter process control no significant yield differences were found.

Porous implant surface is shown to facilitate bone in-growth and cell attachment, improving overall osteointegration, while providing adequate mechanical integrity. Recently, biodegradable material possessing such superior properties has been the focus with an aim of revolutionizing implant’s design, material and performance. This paper aims to present a comprehensive investigation into the design and development of low elastic modulus porous biodegradable Mg-3Si-5HA composite by mechanical alloying and spark plasma sintering (MA-SPS) technique.

This paper presents a comprehensive investigation into the design and development of low elastic modulus porous biodegradable Mg-3Si-5HA composite by MA-SPS technique. As the key alloying elements, HA powders with an appropriate proportion weight 5 and 10 are mixed with the base elemental magnesium (Mg) particles to form the composites of potentially variable porosity and mechanical property. The aim is to investigate the performance of the synthesized composites of Mg-3Si together with HA in terms of mechanical integrity hardness and Young’s moduli corrosion resistance and in-vitro bioactivity.

Mechanical and surface characterization results indicate that alloying of Si leads to the formation of fine Mg2 Si eutectic dense structure, hence increasing hardness while reducing the ductility of the composite. On the other hand, the allying of HA in Mg-3Si matrix leads to the formation of structural porosity (5-13 per cent), thus resulting in low Young’s moduli. It is hypothesized that biocompatible phases formed within the composite enhanced the corrosion performance and bio-mechanical integrity of the composite. The degradation rate of Mg-3Si composite was reduced from 2.05 mm/year to 1.19 mm/year by the alloying of HA elements. Moreover, the fabricated composites showed an excellent bioactivity and offered a channel/interface to MG-63 cells for attachment, proliferation and differentiation.

Overall, the findings suggest that the Mg-3Si-HA composite fabricated by MA and plasma sintering may be considered as a potential biodegradable material for orthopedic application.

This paper aims to cover all the aspects of development, investigation and analysis phases to evaluate the slurry erosion performance of test coatings. The powders having composition of Ni-20Al₂O₃ and Ni-15Al2O₃-5TiO₂ were deposited on CA6NM grade turbine steel by using high velocity flame spray (HVFS) technique. The characterization of the coatings was done with the help of SEM/EDS and XRD techniques. Various properties such as micro-hardness and bonding strength of the coatings were also evaluated. Thereafter, these coatings were subjected to an indigenously developed high speed slurry erosion tester at different levels of rotational speed, erodent particle size and slurry concentration. The effect of these parameters on the erosion behavior of coatings was also evaluated. The slurry erosion tests and SEM of the eroded surfaces revealed remarkable improvement in slurry erosion resistance of Ni-15Al₂O₃-5TiO₂ coating in comparison with Ni-20Al₂O₃ coating.

Two different compositions of HVFS coating were developed onto CA6NM steel. Subsequently, these coatings were evaluated by means of mechanical and microstructural characterization. Further, slurry erosion testing was done to analyze the erosive wear behavior of developed coatings.

The coatings were successfully developed by HVFS process. Cross-sectional microscopic analysis of sprayed coatings revealed a continuous and defect-free contact between substrate and coating. Ni-15Al₂O₃-5TiO₂ coating showed higher value of bond strength in comparison with Ni-20Al₂O₃ coating. Under all the testing conditions, Ni-15Al₂O₃-5TiO₂ coatings showed higher resistance to slurry erosion in comparison with Ni-20Al₂O₃ coatings. Rotational speed, average particle size of erodent and slurry concentration were found to have proportional effect on specific mass loss of coatings. The mixed behavior (brittle as well as ductile) of the material removal mechanism was observed for the coatings.

From the literature review, it was found that researchers have documented the various studies on Ni-Al₂O₃, Ni-TiO₂ and Al₂O₃-TiO₂ coatings. No one has ascertained the synergetic effect of Alumina and Titania on the slurry erosion performance of Nickel-based coating. In view of this, the authors have developed Ni-Al₂O₃ and Ni-Al₂O₃-TiO₂ coatings, and an attempt has been made to compare their mechanical, microstructural and slurry erosion characteristics.

The purpose of this paper is to develop a new improved solution and a new model to predict both shear and normal interfacial stress in simply supported beams strengthened with bonded prestressed FRP laminates by taking into account the fiber volume fraction spacing that play an important role on the interfacial stresses concentration.

The study has been conducted by using analytical approaches for interfacial stresses in plated beams. The analysis is based on the deformation compatibility approach where both the shear and normal stresses are assumed to be invariant across the adhesive layer thickness. In addition, an unrealistic restriction of the same curvatures in the RC beam and FRP panel commonly used in most of the existing studies is released in the present theoretical formulation.

To verify the analytical model, the present predictions are compared first with those of (Malek et al., 1998; Smith and Teng, 2001) in the case of the absence of the prestressing force; for the second time, the present method is compared with that developed by (Al-Emrani and Kliger, 2006; Benachour et al., 2008) in the case where only the prestressing force is applied. From the presented results, it can be seen that the present solution agree closely with the other methods in the literature.

The paper puts in evidence a new originality approach theory, taking into account the mechanical load, and the prestressed FRP plate model having variable fiber spacing which considers a strength rigidity and resistance of the damaged structures, which is one aspect that has not been taken into account by the previous studies.