In this paper, the edgewise and flatwise compressive behaviour of an innovative sandwich panel, mainly developed for quick assembly of post-disaster housing as well as load bearing panels for pre-fabricated modular construction and semi-permanent buildings, is investigated experimentally and by finite element modelling. The panel is composed of two 3-D high-density polyethylene (HDPE) sheets as the skins, filled with high-density Polyurethane (PU) foam as the core. HDPE sheets manufactured with a studded surface considerably enhance the stress distribution and buckling performance of the sandwich panel. Material characterisation tests and flatwise compression and edgewise compression experiments were performed in accordance with ASTM standards to evaluate the compressive strength and the load-carrying behaviour of the sandwich panels. A finite element analysis and validation were also conducted to model the compressive behaviour of sandwich structures. Results demonstrate that the developed sandwich panel exhibits very good compressive performance.

This paper illustrates an innovative manufacturing procedure for producing handcrafted interlocking stabilized compressed earth blocks (ISCEBs). A comparison of the mechanical properties of ISCEBs is conducted to assess the influence of varying components. The ISCEBs are manufactured by employing different block densities with three distinct mixtures (earth, earth and lime, earth and straw) and by using a human-powered machine named Float RAM 1.0 Press. The manual press was conceived for regions with limited access to technology and allows the production of interlocking blocks via two modes of compaction: mono-directional and bi-directional. A production average of approximately 30 blocks/hour corresponding to the work of three people is achieved. Three-point bending tests and uniaxial compression tests are carried out to investigate the ISCEB mechanical behaviour. The improvements obtained by incorporating additives into the subset of ISCEBs made from a pure earth mixture are tested. The aim of this work is to identify, for this specific technology, the relationship between production parameters and the consequent behaviour of different stabilization methods. A correlation is found between the compaction force and the compression strength of ISCEBs. The addition of lime increases strength and causes the blocks to exhibit a brittle behaviour. Moreover, the incorporation of straw fibres improves the tensile strength and ductility without significantly affecting the compression strength of the blocks. Energy-based parameters are obtained for all the tests, allowing the assessment of the ISCEB mechanical and dissipation properties.

Simulation and visualization of the mechanical components have become a predominant phase during the design and the production stages. Several means are used to improve the design and to reduce study time. Today, the powerful hardware and the software available on the market have contributed greatly on the improvement of design, visualization and manufacturing process of complex parts (turbine blade). In this context, our study is a contribution to the establishment of a methodology to a CAD modelling and finite element analysis, which allows us to identify the mechanical behavior of a gas turbine blade. The profile of the blade turbine model is obtained after regeneration using the CATIA V5R20 software from the retro-design technique using a FARO-type scanner. The turbine blade is analyzed under a static mechanical behavior. It has been observed that the maximum stresses and deformations are located in the vicinity of the root and the upper surface along the turbine blade. On the other hand, the elastic energy is located at a distance from the root of the turbine blade.

In this paper, an innovative and efficient sandwich panel is proposed for the structural walls for quickly assembled post-disaster housing, as well as load bearing panels for pre-fabricated modular construction and semi-permanent buildings. This study focuses on the flexural and shear behavior of the innovative sandwich panels, which is composed of two 3-D high density polyethylene (HDPE) skins, and high-density Polyurethane (PU) foam core. An experimental study was carried out to validate the effectiveness of this panel for increasing the ultimate bending strength. A series of experimental tests were performed on medium-scale specimens to characterize their core shear behavior. Then, some supplementary tests were run to determine the panels’ flexural and shear stiffness. The numerical and experimental investigations show that the 3-D-HDPE sheets, manufactured with a studded surface; considerably enhance the pull-out and delamination strength. Good agreement has been observed between the numerical and experimental tests.

The battery packs are one of the most vulnerable parts of satellites for damages induced by vibration and shock during launch process. This is due to their considerable weight which increases their susceptibility for structural damage and short connection. Therefore, the related components have to pass successfully ground dynamic and vibration tests in order to verify the dynamic design of such component and ensure the successful performance of a space mission. In this paper, first a new design is presented for a battery pack of a microsatellite and then the verification of designed and manufacturing pack is done by performing some vibration tests based on the European space standard (ECSS). It was shown that the designed battery pack which uses circular or radial type arrangement for the battery cell layout can suitably pass the mechanical vibration tests applied to the pack during the lunch.

Friction drilling is a green hole-making process that zealously utilizes the heat generated from the friction between the rotating conical tool and workpiece to create a bushing without generating chip. The difficult-to-machine materials with unique metallurgical properties have been developed to meet the demands of extreme applications. However, the major challenges of friction drilling on difficult-to-machine materials are the hole diameter accuracy, petal formation and tool wear. In this study, the effects of process parameters such as spindle speed and feed rate on bushing height and shape, hardness and tool wear in friction drilling of titanium alloy Ti-6Al-4V were experimentally investigated using tungsten carbide tool. Optical photographs have also been analyzed for better understanding of the chipless friction drilling process for different parametric settings. Experimental results indicated that the spindle speed has great influences for achieving better bushing formation and prolong the tool life. It was confirmed that the low spindle speed and low feed rate have great influences for achieving better bushing shape and height, prolong tool life and lower hardness that located adjacent to the hole wall. It also was discovered that the low thermal conductivity of Ti-6Al-4V caused to improper increment of frictional heat and surface temperature. This disadvantage leads to unsatisfactory bushing formation. This work demonstrated the performances of chipless friction drilling used on difficult-to-machine material that can offer a great prospective for a new product design and manufacturing.

This paper describes laboratory tests on twelve simply-supported one-way slabs including four lightweight concrete slabs in this study and previously conducted experiments on eight self-compacting reinforced concrete slabs subjected to loading at the age of 14 days. All slab were identical by dimensions of 3.8 m long supported on 3.5 m span, 400 mm wide, and 161 mm deep with 4N12 bars at an effective depth of 136 mm providing a reinforcement ratio of 0.008. After seven days moist-curing, the specimens were removed from the formworks and subjected to different values of the uniformly distributed loading including the self-weight of slabs. The mid-span deflection of slabs was recorded immediately after putting the loading blocks on the slabs. Despite close values of the compressive strength of the mixtures, the obtained results validate the effect of the concrete type on the instantaneous deflection of slabs. A wide range of existing models of the effective stiffness of reinforced concrete section were investigated to predict the instantaneous deflection of slabs. Majority of the models are developed for conventional concrete. Comparing the predicted and experimental results of mid-span deflection confirmed that the existing models are inadequate for lightly reinforced specimens such as slabs. New models are proposed and verified to predict the effective moment of inertia in the slabs with and without fiber reinforcing concretes.

An in-house finite element code was utilized to evaluate mode I/II stress intensity factor (SIF) of an edge cracked semi-circular disc subjected to three-point bending. The specimen was considered as an isotropic and homogeneous material. Relative span length ratios of 0.3 to 0.8 in steps of 0.1 were invoked. Relative crack length ratios of 0.1, 0.2, 0.3, 0.4, 0.5 and 0.6 were analyzed with crack angles up to 60° in steps of 5°. At the same crack length, mode I SIF decreases with increasing crack angle or decreasing the span length. The range of pure mode II decreases with increasing the span length. For the same crack length, the crack angle corresponding to the transition from a mixed mode I/II to a pure mode II increases with increasing the relative span length ratio. On the contrary, that angle decreases with increasing the crack length for the same span length. Good agreement has been generally obtained with relevant results found in the literature.

Linear matching method (LMM) is one of the effective numerical methods for the limit and shakedown analysis, which computes the converging upper series by solving iteratively linear elastic analysis with Young’s modulus varying in space. LMM, which is capable of implementing by using the commercial finite element packages such as ABAQUS and ANSYS has been widely used in the practical applications including fatigue, creep and composite analysis. Nevertheless, LMM could not ensure numerical accuracy for discontinuous problems such as crack analysis since it computes the mechanical quantities including stress, strain and displacement on the base of conventional finite element method, likewise other numerical methods for the limit and shakedown analysis. Meanwhile, extended finite element method (XFEM), recently proposed, is an attractive numerical method for the analysis of discontinuous problems which enriches finite element approximate space by some special functions. In this paper, authors proposed a very straightforward method for the limit analysis by the combination of XFEM with LMM. Numerical validation is done for two types of typical fracture specimens. Numerical examples show that the limit analysis by combining XFEM with LMM gives more accurate result compared with the one by combining of conventional finite element method with LMM. Furthermore, we demonstrated that the choice of enrichment region plays an important role in the improvement of numerical accuracy of our proposed method.

Friction Stir Welding (FSW) is a relatively new solid state joining technique which is used not only for joining the aluminum and its alloys but also has potential for joining dissimilar materials with very different physical and mechanical properties which are hard to weld using conventional fusion welding processes. Tensile shear testing is used to determine the Mechanical strength of friction stir lap (FSL) welds under static loading, fracture strength (σLap) corresponding to the maximum load in a test over the sample width is widely used as the strength value. During friction stir lap welding (FSLW) of dissimilar metals with large differences in melting temperatures, a metallurgical bond is established through the formation of interfacial intermetallic compounds. However, as these intermetallic compounds are generally believed to be brittle with little ductility, they are generally considered to have detrimental effect on fracture strength. The aim of the present research is to study how the interface structure is affected by FSW parameters and how the formation of interface structure affects fracture of Al-Steel and Al-Ti FSL welds.