Experimental and theoretical investigation on flexure performance of pultruded GFRP composite beams with damage analyses

In the first part of this two-part comprehensive study, mechanical properties and machinability characteristic of filament wound hybrid composite pipes with various stacking sequences of glass and carbon fibers (Glass-Carbon-Glass (GCG), Carbon-Glass-Glass (CGG), and Glass-Glass-Carbon (GGC)) were investigated experimentally. In order to determine the mechanical properties of the pipes, hardness test (Shore D), ring tensile test (ASTM D2290), and burst test (ASTM D1599) were carried out. Machinability tests were performed at various feed rates (50, 150, 250 and 350 mm/min) and spindle speeds (796, 1592, 2388 and 3184 rpm) using with and without a back-up. The results showed that stacking of the carbon layer between two glass layers (GCG) presented better performance in terms of mechanical properties and machinability characteristic. The maximum ring tensile stress of GCG specimen is 27% and 19% higher than those of GGC and CGG specimens, respectively. On the other hand, the lowest thrust forces measured during the drilling of GCG specimen while the GGC represented highest values. In addition, the use of back-up led to an increase in thrust force. The highest increase was observed in GGC sample. In GGC sample, a change in a spindle speed increased thrust force by 18–35%, while a change in feed rate increased thrust force by 20–30%.

The effects of stacking sequence on drilling machinability of filament wound hybrid composite pipes: Part-1 mechanical characterization and drilling tests

Buckling and free vibration analyses of pultruded GFRP laminated composites: Experimental, numerical and analytical investigations

An overview of burst, buckling, durability and corrosion analysis of lightweight FRP composite pipes and their applicability

The main objective of this research is to investigate the damage progression and the failure mechanism of Glass-Fiber Reinforced-Plastic (GFRP) pipes subjected to compressive transverse loading. An experimental study is performed to observe the level of diametric deflection where failure takes place under transverse loading and also to monitor experienced failure mode. Then, conducted experimental study is simulated in commercial finite element software taking into account both interlaminar and intralaminar failure modes, simultaneously. The degree to which the pipe can withstand diametric deflection without experiencing any failure mode is extracted. Then, appropriate in-plane failure criteria are chosen for identifying the onset of in-plane failure mode while cohesive approach is employed for identifying the initiation of delamination as the out-of-plane failure mode. Results of numerical simulation reveal that the liner is debonded from its adjacent hoop layer at 27% diametric deflection which is in a reasonable agreement with experimentally observed 31%. Moreover, the magnitude of the reaction force at 5% diametric deflection is obtained as 1242 N which is in a good agreement with experimentally measured 1225 N. Therefore, a satisfactory level of accuracy is achieved in constructed model implying on the appropriate modeling of damage progression. Finally, a parametric study is conducted to investigate the influence of various effective parameters on the pipe resistance level against transverse loading wherein neither in-plane nor out-of-plane failure is experienced.

Evaluating mechanical performance of GFRP pipes subjected to transverse loading

The main objective of this study is to predict the stiffness of GFRP pipes subjected to compressive transverse loading. An experimental study is performed to measure the stiffness of a composite pipe with a core layer of sand/resin composites. Then, a simple analytical modeling constructed on the basis of solid mechanics is used to estimate the stiffness of the investigated pipe as the back-of-envelope technique widely used by industrial sectors. The simulation of stiffness test is conducted using finite element modeling wherein both large deformation and inelastic behavior of material is taken into account as the sources of nonlinearity. The results reveal that a very good estimation with high level of accuracy can be reached by proper selection of the element and performing nonlinear analysis.

On The Stiffness Prediction of GFRP Pipes Subjected to Transverse Loading

The effect of delamination on the stiffness reduction of composite pipes is studied in this research. The stiffness test of filament wound composite pipes is simulated using cohesive zone method. The modeling is accomplished to study the effect of the geometrical parameters including delamination size and its position with respect to loading direction on stiffness of the composite pipes. At first, finite element results for stiffness test of a perfect pipe without delamination are validated with the experimental results according to ASTM D2412. It is seen that the finite element results agree well with experimental results. Then the finite element model is developed for composite pips with delaminated areas with different primary shapes. Thus, the effect of the size of delaminated region on longitudinal and tangential directions and also its orientation with respect to loading direction on delamination propagation and stiffness reduction of the pipes is assessed.

Investigating the influence of delamination on the stiffness of composite pipes under compressive transverse loading using cohesive zone method

As a noticeable focal point in the field of analysis tools, Social Network Analysis (SNA) has received much interest to model real-world phenomena in a variety of domains, e.g., research collaboration and have a better perception of social events. Research collaboration refers to the main procedure of integrating disorganized capabilities and knowledge into novel research techniques and ideas. The invaluable analytical indicator of research collaboration is the outcome of analyses of scientific articles developed as its achievements. This article investigates collaboration and co-authorship in the Process Mining field based on the already published dataset consisting of 1278 papers which are selected by their keywords or snowball technique. According to crucial results, the co-authorship network developed among researchers features a number of the properties of the scale-free networks. Additionally, using mathematics, it has been proven that the acquired network is small world network. Besides, most central authors are determined by integrating four centrality measures include closeness, degree, eigenvector, and betweenness via TOPSIS. This network has been compared and reviewed in the absence/presence of such actors. In accordance with the obtained affiliation of the high-ranking authors, TU/e university plays the most pivotal role in Process Mining promotion. 

Mohammad Reza Habibagahi

Papers

Evaluating mechanical performance of GFRP pipes subjected to transverse loading

On The Stiffness Prediction of GFRP Pipes Subjected to Transverse Loading

Investigating the influence of delamination on the stiffness of composite pipes under compressive transverse loading using cohesive zone method

On the Co-authorship network analysis in the Process Mining research Community: A social network analysis perspective