Papers by Keyword: Composite Panel

Abstract: This paper investigates the behaviour of a bio-inspired finite element composite model (that mimics the structure of nacre, the inner layer of molluscan shells) under blast loading. Nacre, which has attracted the attention of researchers over the past few decades, comprises 95% aragonite, brittle voronoi-like polygonal tablets that are joined by an organic matrix and arranged in a brick and mortar type structure. In this work, the finite element model developed herein was constructed using voronoi diagrams and geometric algorithms capable of automatically generating staggered layers of voronoi-like aluminium tablets bonded together by a vinylester adhesive layer. Many studies have led to the belief that the magnificent toughness of nacre is mainly attributed to the inter-platelet adhesive bonds. Results obtained from the finite element analysis show that this is indeed true, and it is imperative that the adhesive bond exhibits adequate toughness in order to be able to spread damage across the entire composite, thereby delaying localised failure.

Abstract: In this study, a finite element model was developed to understand the deformation and failure mechanisms of a multi-layered composite panel under blast. Fibre (E-glass fiber) and matrix (vinylester resin) damage and degradation of individual unidirectional composite laminas were modelled using the Hashin failure model. The delamination between laminas was modelled by a traction-separation cohesive law. A Polyurea layer was placed at the rear of the panel to study its effects on the damage evolution in the composite laminas, and was modelled using a Mooney-Rivlin constitutive law. The model-predicted deformation histories, fiber/matrix damage patterns, and inter-lamina delamination were compared between monolithic and composite panels. The model revealed that the Polyurea plays an important role in improving the panel’s performance.

Abstract: Using an adjusted explosive welding technique, a Zr-2 alloy plate, a titanium plate and a carbon steel plate were cladded to form a three-layer composite panel which is difficult to manufacture by common methods. Microstructural evaluations reveal that a metallurgical bonding interface with wave morphology is realized, and the grains near the interface are smaller than grains in other areas. The microhardness of the sample near the interface is greatly higher than that of other areas. Furthermore, mechanical experimental evidence indicates the shearing strength of the interface in the moderate condition exceeds that of the interlayer plate.

Abstract: This study examines the effect of different variables of Profiled Steel Sheet (PSS) on various aspects of Profiled Steel Sheet Dry Board (PSSDB) system. PSS is an important component of PSSDB. The sensitivity of PSS variables at the 70% to 140% of Peva45 dimensions, the profiled steel sheet at local markets, to the cross-sectional area of PSS, the ultimate load carrying capacity, and the flexural stiffness of the PSSDB system is analysed. Results are shown in charts, and the most effective variables are determined. The dominant variables are found by saving computational time in the optimization of PSS in the PSSDB system.

Abstract: Within the bilateral scientific project between the Institute of Earthquake Engineering and Engineering Seismology - UKIM-IZIIS, St. Cyril and Methodius University, Skopje, Republic of Macedonia and the Civil Engineering Faculty, University of Zagreb, Croatia, experimental testing of full scale composite timber-glass innovative panels was carried out on the seismic shaking table at IZIIS for the purpose of defining their behaviour and stability under real earthquake conditions. The seismic excitations selected for the shake-table testing of the model were four representative accelerograms recorded during the following earthquakes: El Centro, Petrovac, Kobe and Friuli. The idea was to investigate the seismic behavior of the model under several types of earthquakes, considering their different frequency content, peak acceleration and time duration. The performed tests showed clearly the behaviour of the composite panels and the failure mechanism under strong earthquake motion.

Abstract: Laminated composite structures are increasingly finding more applications in various fields thanks to their lower weight if compared with other materials of the same strength. Nevertheless, composites thin plates show a critical behavior in terms of damage propagation mechanisms when subjected to (low velocity) impact. Indeed they tend to produce delaminations which can be hardly detected by optical inspections and can affect the global load carrying capability, leading to a premature structural collapse. The aim of this paper is to assess the capabilities of the Davies-Zhang approach (introduced in 1994 and aimed to the estimation of both the delamination initiation impact load and the size of the impact induced delaminations) by using a multiscale FE model based on the mesh superposition technique. Indeed the impact area has been modeled layer-wise with an element per layer while the rest of the structure has been modeled at laminate level by layered elements by means of a homogenization approach for the determination of the equivalent laminate material properties. The impact induced delamination area has been determined by adopting stress-based criteria. The results (in terms of delamination initiation impact force and delamination size) have been compared to the ones obtained by adopting the Davies-Zhang approach.

Abstract: This paper analyzed the results and the status of China's building energy efficiency, explored the new areas of building energy in future: the building industrialization. Moreover, some types of building industrialization and their advantages such as energy-saving, environmental protection, waste usage, economy, and higher industrialization were introduced. As long as some problems and deficiencies are overcome, building industrialization would promote the building energy efficiency to achieve “Four saving and Environment protection” enormously in China.

Abstract: In this paper, a practical design procedure for thin-skinned steel-composite composite panels subjected to axial or flexural loadings is developed. Ignoring the adhesive forces between steel and core concrete, steel skins may be modeled as thin plates resting on tensionless rigid or elastic foundations (concrete material). Sections of steel skin tend to become separated (delaminated) from the core concrete and buckle away from it, while other areas keep contact with the inside material. This phenomenon is named as contact buckling. Based on the governing equations of thin plates in contact area and noncontact area, initial buckling response of thin skins may be obtained. Then it becomes possible to use effective width-based formulas to deduce ultimate strengths of the unilaterally constrained skins. At last, design formulas for section capacity of composite members due to axial and flexural loadings are developed.

Abstract: The study involving utilization of agricultural residue is gaining attention. This is an attempt to investigate the possibility of producing composite panels from rice husk (RH), an abundant source of agricultural residues. Composite panels were produced by mixing 1mm of rice husk with a commercial binder called urea formaldehyde at different density levels namely 650kg/m3, 700kg/m3 and 750kg/m3. Two types of resin content (10% and 12%) were used. Mechanical strength tests were performed on the panels conforming to British Standard (BS EN 310). Results obtained indicated that the modulus of elasticity (MOE) increased up to 1753.98MPa at 750kg/m3 density level with 12% resin content. Similarly, modulus of rupture (MOR) increased up to 8.08MPa with increase in panel density and amount of resin content. Thus, the potential of producing reasonably good composite panels from rice husk for specific end usage is very promising.

Abstract: Previous studies have indicated that Chinese fir glulam has many defects on surface: color is singleness, knot is more, surface is roughness, etc. This paper presents a study on the manufacturing technology of sliced bamboo veneer-Chinese fir glulam composite panel. Sliced bamboo veneer were glued on both the top and bottom surface of Chinese fir glulam. The results showed: (1)sliced bamboo veneer can beautify the surface of Chinese fir glulam; (2)sliced bamboo veneer should directly overlay on the surface of Chinese fir glulam, and it is not suitable back lining non-woven fabric in gluing; (3)the optimal composite technological parameters are: unit pressure: 0.7MPa; hot pressing temperature: 100°C; hot pressing time: 4min.