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As an advanced manufacturing method, additive manufacturing (AM) technology provides new possibilities for efficient production and design of parts. However, with the continuous expansion of the application of AM materials, subtractive processing has become one of the necessary steps to improve the accuracy and performance of parts. In this paper, the processing process of AM materials is discussed in depth, and the surface integrity problem caused by it is discussed.

Firstly, we listed and analyzed the characterization parameters of metal surface integrity and its influence on the performance of parts and then introduced the application of integrated processing of metal adding and subtracting materials and the influence of different processing forms on the surface integrity of parts. The surface of the trial-cut material is detected and analyzed, and the surface of the integrated processing of adding and subtracting materials is compared with that of the pure processing of reducing materials, so that the corresponding conclusions are obtained.

In this process, we also found some surface integrity problems, such as knife marks, residual stress and thermal effects. These problems may have a potential negative impact on the performance of the final parts. In processing, we can try to use other integrated processing technologies of adding and subtracting materials, try to combine various integrated processing technologies of adding and subtracting materials, or consider exploring more efficient AM technology to improve processing efficiency. We can also consider adopting production process optimization measures to reduce the processing cost of adding and subtracting materials.

With the gradual improvement of the requirements for the surface quality of parts in the production process and the in-depth implementation of sustainable manufacturing, the demand for integrated processing of metal addition and subtraction materials is likely to continue to grow in the future. By deeply understanding and studying the problems of material reduction and surface integrity of AM materials, we can better meet the challenges in the manufacturing process and improve the quality and performance of parts. This research is very important for promoting the development of manufacturing technology and achieving success in practical application.

This paper aims to review recent literature results on the mechanical response of confined pentamode structures behaving either in the stretching-dominated or the bending-dominated regimes.

The analyzed structures consist of multilayer systems formed by pentamode lattices alternated with stiffening plates and are equipped with rigid or hinged connections.

It is shown that such structures are able to carry unidirectional compressive loads with sufficiently high stiffness, while showing markedly low stiffness against shear loads. In particular, their shear stiffness may approach zero in the stretching-dominated regime.

The presented results highlight the high engineering potential of laminated pentamode metamaterials as novel isolation devices to be used for the protection of buildings against shear waves.

This study aims to research the development trend, research status, research results and existing problems of the steel–concrete composite joint of railway long-span hybrid girder cable-stayed bridge.

Based on the investigation and analysis of the development history, structure form, structural parameters, stress characteristics, shear connector stress state, force transmission mechanism, and fatigue performance, aiming at the steel–concrete composite joint of railway long-span hybrid girder cable-stayed bridge, the development trend, research status, research results and existing problems are expounded.

The shear-compression composite joint has become the main form in practice, featuring shortened length and simplified structure. The length of composite joints between 1.5 and 3.0 m has no significant effect on the stress and force transmission laws of the main girder. The reasonable thickness of the bearing plate is 40–70 mm. The calculation theory and simplified calculation formula of the overall bearing capacity, the nonuniformity and distribution laws of the shear connector, the force transferring ratio of steel and concrete components, the fatigue failure mechanism and structural parameters effects are the focus of the research study.

This study puts forward some suggestions and prospects for the structural design and theoretical research of the steel–concrete composite joint of railway long-span hybrid girder cable-stayed bridge.

This study aims to model scale effects in nano-beams under torsion.

The elastostatic problem of a nano-beam is formulated by a novel stress-driven nonlocal approach.

Unlike the standard strain-driven nonlocal methodology, the proposed stress-driven nonlocal model is mathematically and mechanically consistent. The contributed results are useful for the design of modern devices at nanoscale.

The innovative stress-driven integral nonlocal model, recently proposed in literature for inflected nano-beams, is formulated in the present submission to study size-dependent torsional behavior of nano-beams.

This purpose of this paper is to quantify the effect of local instability arising from high shear loading on response of steel girders subjected to fire conditions.

A three-dimensional nonlinear finite element model able to evaluate behavior of fire-exposed steel girders is developed. This model, is capable of predicting fire response of steel girders taking into consideration flexural, shear and deflection limit states.

Results obtained from numerical studies show that shear capacity can degrade at a higher pace than flexural capacity under certain loading scenarios, and hence, failure can result from shear effects prior to attaining failure in flexural mode.

The developed model is unique and provides valuable insight (and information) to the fire response of typical hot-rolled steel girder subjected to high shear loading.

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.

The purpose of this paper is to describe the approach for the design of cowlings for a new fast helicopter from the perspective of airworthiness requirements regarding high-speed impact resistance.

Validated numerical simulation was applied to flat and simple curved test panels. High-speed camera measurement and non-destructive testing (NDT) results were used for verification of the numerical models. The final design was optimized and verified by validated numerical simulation.

The comparison between numerical simulation based on static material properties with experimental results of high-speed load shows no significant influence of strain rate effect in composite material.

Owing to the sensitivity of the composite material on technology production, the results are limited by the material used and the production technology.

The application of flat and simple curved test panels for the verification and calibration of numerical models allows the optimized final design of the cowling and reduces the risk of structural non-compliance during verification tests.

Numerical models were verified for simulation of the real composite structure based on high-speed camera results and NDT inspection after impact. The proposed numerical model was simplified for application in a complex design and reduced calculation time.

The purpose of this study concerns numerical studies and experimental validation of the mechanical behavior of hybrid specimens. These kinds of composite specimens are made up of thin carbon and glass substrates on which some Macro Fiber Composite^® (MFC) piezoelectric patches are glued. A proper design and manufacturing of the hybrid specimens as well as testing activities have been performed. The research activity has been carried out under the FutureWings project, funded by the European Commission within the 7th Framework.

The paper describes the basic assumptions made to define specimen geometries and to carry out experimental tests. Finite element (FE) results and experimental data (laser technique measurements) have been compared: it shows very good agreement for the displacements’ distribution along the specimens.

Within the objectives of the project, the study of passive and active deformation characteristics of the hybrid composite material has provided reference technical data and has allowed for the correct adaptation of the FE models. More in particular, using the hybrid specimens, both the bending deformations and the torsion deformations have been studied.

The deformation capability of the hybrid specimens will be used in the development of prototypical three-dimensional structures, that, through the electrical control of the MFC patches, will be able to change the curvature of their cross section or will be able to change the angle of torsion along their longitudinal axis.

The design of nonstandard specimens and the tests executed represent a novelty in the field of structures using piezoelectric actuators. The numerical and experimental data of the present research constitute a small step forward in the field of smart materials technology.

This paper aims to provide an overview of the current manufacturing methods for three-dimensional textile preforms while providing experimental data on the emerging techniques of combining yarn interlocking with yarn interlooping.

The paper describes the key textile technologies used for composite manufacture: braiding, weaving and knitting. The various textile preforming methods are suited to different applications; their capabilities and end performance characteristics are analysed.

Such preforms are used in composites in a wide range of industries, from aerospace to medical and automotive to civil engineering. The paper highlights how the use of knitting technology for preform manufacture has gained wider acceptance due to its flexibility in design and shaping capabilities. The tensile properties of glass fibre knit structures containing inlay yarns interlocked between knitted loops are given, highlighting the importance of reinforcement yarns.

The future trends of reinforcement yarns in knitted structures for improved tensile properties are discussed, with initial experimental data.

3-ply cross-laminated timber (CLT) is used to investigate the thermo-mechanical performance of intermediate-size assemblies comprised of T-shaped welded slotted-in steel doweled connections and CLT beams at ambient temperature (AT), after and during non-standard fire exposure.

The first set of experiments was performed as a benchmark to find the load-carrying capacity of the assembly and investigate the failure modes at AT. The post-fire performance (PFP) test was performed to investigate the residual strength of the assembly after 30-min exposure to a non-standard fire. The fire-performance (FP) test was conducted to investigate the thermo-mechanical behavior of the loaded assembly during non-standard fire exposure. In this case, the assembly was loaded to 67% of AT load-carrying capacity and partially exposed to a non-standard fire for 75 min.

Embedment failure and plastic deformation of the dowels in the beam were the dominant failure modes at AT. The load-carrying capacity of the assembly was reduced to 45% of the ambient capacity after 30 min of fire exposure. Plastic bending of the dowels was the principal failure mode, with row shear in the mid-layer of the CLT beam and tear-out failure of the header sides also observed. During the FP test, ductile embedment failure of the timber in contact with the dowels was the major failure mode at elevated temperature.

This paper presents for the first time the thermo-mechanical performance of CLT beam-to-girder connections at three different thermal conditions. For this purpose, the outside layers of the CLT beams were aligned horizontally.

1. Load-carrying capacity and failure modes of CLT beam-to-girder assembly with T-shaped steel doweled connections at ambient temperature presented.

2. Residual strength and failure modes of the assembly after 30-min partially exposure to the non-standard fire provided throughout the post-fire performance test.

3. Fire resistance of the assembly partially exposed to the non-standard fire highlighted.

Load-carrying capacity and failure modes of CLT beam-to-girder assembly with T-shaped steel doweled connections at ambient temperature presented.

Residual strength and failure modes of the assembly after 30-min partially exposure to the non-standard fire provided throughout the post-fire performance test.

Fire resistance of the assembly partially exposed to the non-standard fire highlighted.