Superior Stiffness Research Articles

Study on the free vibration analysis and mechanical behaviour of 3D printed composite I shaped beams made up of short carbon fiber reinforced ABS and PLA materials

Rapid prototyping is a process that involves creating physical models of products or components quickly using 3D printing technology. Two of the most used materials for this purpose are Polylactic Acid (PLA) and Acrylonitrile Butadiene Styrene (ABS). Both have unique properties that make them suitable for different applications. When it comes to constructing buildings, bridges, and other structures, one of the most important components is the beam. Beams are used to support weight and provide stability for a structure. One type of beam that is commonly used in construction projects is a box-shaped beam. Hence in this research work, I shaped beam is designed and fabricated using Fused Filament fabrication method, material used are carbon fiber reinforced PLA and ABS materials. Vibration tests can help determine whether a particular design has sufficient stiffness and damping characteristics for its intended application, which helps reduce the risk of unexpected failures down the line. I shaped beam is subjected to free vibration test using Impulse hammer test condition, natural frequency and damping of the I shaped beam for the considered composites were extracted. Results show that the ABS reinforced with carbon fiber is superior in damping than the PLA reinforced with the same short carbon fiber material. Flexural tests are conducted as per ASTM standards and results were correlated with respect to the stiffness of the material under transverse vibration. The results indicated that the I shaped ABS reinforced with carbon fiber had superior stiffness and damping characteristics than PLA reinforced with the same short carbon fiber material, making it a better choice for design applications which require strength and flexibility.

Artificial intelligence-enhanced bioinspiration: Design of optimized mechanical lattices beyond deep-sea sponges

Euplectella aspergillum, as a textbook example presented by nature, is famous for its superior buckling resistance and stiffness subject to compression of arbitrary directions and its double-diagonal reinforced square microstructure has attracted considerable interest. In the present work, a parametric model is developed for a class of sponge-like lattices, and a neural network model is trained to realize accurate and efficient mapping from the geometry parameters to the corresponding effective stiffness and buckling resistance under uniaxial compression along all directions. Then an optimization formulation is proposed for designing a sponge-like lattice with on-demand requirements. Using the same amount of material, in the present design framework, the average buckling resistance of the original sponge-lattice model in literature is increased by about 40% and the design efficiency is improved by about 3–4 orders as compared to the traditional optimization process with exact mechanical modeling. Combining the intelligence of nature, humans and computers, the present AI-enhanced bioinspiration paradigm provides a novel pathway for designing innovative materials and structural systems.

Load-bearing characteristics of 3D auxetic structures made with carbon fiber reinforced polymer composite

This paper presents a study of 3D novel hybrid auxetic structures made with carbon fiber reinforced polymer (CFRP) laminate composite based on the stretch-dominated mechanism. The homogenized mechanical characteristics of the designed structures, including Young's modulus, shear modulus, and Poisson's ratio, are evaluated via theoretical analysis and finite element simulation. The results exhibit that the structures have negative Poisson's ratio values in all the selected ranges of the design geometry parameters. The multi-objective optimization method is employed to achieve the optimized geometry parameters based on maximizing the stiffness and minimizing the relative density responses. Meanwhile, 2D fabricated auxetic sheets are assembled to build 3D structures through the interlocking method, and quasi-static compressive tests are performed to study their mechanical behaviors. The axial and lateral strains are evaluated by the strain gauge and video extensometer to measure the negative Poisson's ratio values through compressive tests. The results indicate that the proposed structures exhibit superior stiffness and high elongation percentage, suggesting them as a strong candidate for the next generation of load-bearing auxetic structures.

Fatigue and stiffness characteristics of asphalt mixtures made of recycled aggregates

This research studies the stiffness characteristics and fatigue life of several asphalt mixtures made of recycled glass, reclaimed asphalt pavement (RAP), and recycled concrete aggregate (RCA). Experiments were carried out at 5–35 °C, loading frequencies of 0.1–20 Hz, and at two microstrain levels of 200 and 400 µm/m. To date, the effect of extensive parametric combinations of loadings, microstrain levels, and temperatures on asphalt mixtures made entirely of recycled materials (RM) has not been undertaken. The findings exhibited superior stiffness characteristics and improved fatigue life of some RM mixtures compared to control mixtures. The next step of this study included the optimization of three existing fatigue life prediction models. In addition, a prediction model was developed based on nominal maximum aggregate size (NMAS), percentage of RCA, and percentage of RAP in the asphalt mixture. The optimized models resulted in a much higher coefficient of determination (R2) and P-value (likelihood) in the statistical T-test compared to the existing prediction models utilized in this study. The developed model yielded R2 values close to 0.99 between measured and predicted fatigue life, indicating an enhanced accuracy in the prediction. Comparison of the estimated dissipation energy of mixtures supported and validated the fatigue testing outcomes.

Is implant choice associated with fixation strength for displaced radial neck fracture: a network meta-analysis of biomechanical studies

The multitude of fixation options for radial neck fractures, such as pins, screws, biodegradable pins and screws, locking plates, and blade plates, has led to a lack of consensus on the optimal implant choice and associated biomechanical properties. This study aims to evaluate the biomechanical strength of various fixation constructs in axial, sagittal, and torsional loading directions. We included biomechanical studies comparing different interventions, such as cross/parallel screws, nonlocking plates with or without augmented screws, fixed angle devices (T or anatomic locking plates or blade plates), and cross pins. A systematic search of MEDLINE (Ovid), Embase, Scopus, and CINAHL EBSCO databases was conducted on September 26th, 2022. Data extraction was carried out by one author and verified by another. A network meta-analysis (NMA) was conducted in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines. Primary outcomes encompassed axial, bending, and torsional stiffness, while the secondary outcome was bending load to failure. Effect sizes were calculated for continuous outcomes, and relative treatment ranking was measured using the surface under the cumulative ranking curve (SUCRA). Our analysis encompassed eight studies, incorporating 172 specimens. The findings indicated that fixed angle constructs, specifically the anatomic locking plate, demonstrated superior axial stiffness (mean difference [MD]: 23.59 N/mm; 95% CI 8.12–39.06) in comparison to the cross screw. Additionally, the blade plate construct excelled in bending stiffness (MD: 32.37 N/mm; 95% CI − 47.37 to 112.11) relative to the cross screw construct, while the cross-screw construct proved to be the most robust in terms of bending load failure. The parallel screw construct performed optimally in torsional stiffness (MD: 139.39 Nm/degree; 95% CI 0.79–277.98) when compared to the cross screw construct. Lastly, the nonlocking plate, locking T plate, and cross-pin constructs were found to be inferior in most respects to alternative interventions. The NMA indicated that fixed angle devices (blade plate and anatomic locking plate) and screw fixations may exhibit enhanced biomechanical strength in axial and bending directions, whereas cross screws demonstrated reduced torsional stability in comparison to parallel screws. It is imperative for clinicians to consider the application of these findings in constraining forces across various directions during early range of motion exercises, taking into account the distinct biomechanical properties of the respective implants.

Deep Learning Accelerated Design of Mechanically Efficient Architected Materials

Lattice structures are known to have high performance-to-weight ratios because of their highly efficient material distribution in a given volume. However, their inherently large void fraction leads to low mechanical properties compared to the base material, high anisotropy, and brittleness. Most works to date have focused on modifying the spatial arrangement of beam elements to overcome these limitations, but only simple beam geometries are adopted due to the infinitely large design space associated with probing and varying beam shapes. Herein, we present an approach to enhance the elastic modulus, strength, and toughness of lattice structures with minimal tradeoffs by optimizing the shape of beam elements for a suite of lattice structures. A generative deep learning-based approach is employed, which leverages the fast inference of neural networks to accelerate the optimization process. Our optimized lattice structures possess superior stiffness (+59%), strength (+49%), toughness (+106%), and isotropy (+645%) compared to benchmark lattices consisting of cylindrical beams. We fabricate our lattice designs using additive manufacturing to validate the optimization approach; experimental and simulation results show good agreement. Remarkable improvement in mechanical properties is shown to be the effect of distributed stress fields and deformation modes subject to beam shape and lattice type.

The ABH-based lattice structure for load bearing and vibration suppression

Multifunctional 3D lattice structures with unconventional mechanical properties offer unique material properties and broad applications in complex engineering environments. This paper proposes a novel 3D lightweight lattice structure based on the acoustic black hole (ABH) to achieve high load-bearing capability and vibration suppression in the low-frequency domain. In the microunit of the lattice structure, three ABH struts arranged in the X, Y, and Z directions are connected by a center stud and then assembled into a simple cubic lattice (SC) by a body-centered cubic (BCC) support. The proposed SC-BCC-ABH lattice structure is analyzed through simulation and experiments to investigate its static stiffness and vibration bandgaps. The results show that the Gibson-Ashby coefficient of SC-BCC-ABH is higher than that of typical lattice structures, indicating that superior stiffness is achieved. For vibration suppression, the proposed lattice structure generates a wide pseudo bandgap with a relative bandwidth of 0.81, which can be further increased to 1.17 by optimizing the structural parameters. The formation mechanism of the board bandgap is closely related to the ABH effect and the coupled vibration between ABH and SC parts. Parametric analysis and optimization procedures are carried out to obtain better static and dynamic performance. The SC-BCC-ABH lattice structure shows great application potential in micro-vibration isolation and impact protection for high-precision devices.

Novel self-similar re-entrant auxetic metamaterials (SREAM): Design, mechanical property, and geometric optimization

In this study, a novel self-similar re-entrant auxetic metamaterial (SREAM) was designed to improve its mechanical performance compared with the conventional re-entrant structure (CRS). Experimental and numerical analyses were carried out to investigate their mechanical performance under quasi-static compression. The mechanical effects of key geometric parameters of inner re-entrants have also been symmetrically investigated to provide the modeling basis for SREAMs’ geometric optimization. It was found that SREAM do well in both stiffness and auxeticity simultaneously. The mechanical performance of SREAMs is highly adjustable via proper configuration on geometric parameters. The proposed SREAM possibly provides superior auxeticity and high stiffness, with adjustable performance.

Effect of nozzle diameter and cross-linking on the micro-structure, compressive and biodegradation properties of 3D printed gelatin/collagen/hydroxyapatite hydrogel

Since the existing polymeric hydrogel inks lack printability, shape fidelity and the desired mechanical properties for bone tissue regeneration, a hydrogel comprised of gelatin (G), collagen (C), and hydroxyapatite (H) nanoparticles is utilized for extrusion-based 3D printing. The rheological characterization of the composite GCH inks was performed to evaluate their printability, while the cuboid column model scaffolds were printed at a printing speed of 8 mm/s by using different needle inner diameters (500 μm/21G, 250 μm/25G, and 200 μm/27G), followed by carbodiimide induced crosslinking for 12 or 24 h. The samples were tested for their micro-structure, swelling, compression and stiffness performance, before and after incubation in an HBSS solution for up to 14 days. The wall diameter of a 3D printed scaffold decreases and pore size increases primarily with the decreasing inner diameter of the nozzles, and secondarily by increasing the crosslinking time. This was supported with their swelling capacity and the creation of new CaP crystals on the scaffold walls' top surfaces by the time of incubation, necessary for cells’ adhesion, proliferation and growth.The compressive modulus and stiffness of the scaffolds increases proportionally with the increase of their wall diameter and the time of crosslinking, and is inversely proportional to their pores size. The scaffold with the smaller pores provides superior modulus and stiffness, even after 14 days of incubation in the physiological solution (i.e. from ∼0.94 to ∼0.71 MPa and from 17 to 20 kPa to 5–9 kPa, respectively). This is comparative with the reported values for gelatin-based composites, and in the range for hard tissue regeneration at non-load bearing sites, as well as cartilage applications.

Role of processing techniques related to Mg-MMCs for biomedical implantation: An overview

Magnesium is one of the lightest structural metals currently available, and it can replace conventional alloys in mass-saving applications while still offering superior stiffness and strength. The presence of reinforcing components inside the metallic matrix has a substantial impact on stiffness, specific strength, wear behaviour, damping behaviour, and creep qualities when compared to conventional engineering materials. Due to their superior physical and mechanical characteristics, low density, and suitability for a variety of applications, magnesium metal matrix composites are ideal materials. This paper describes how to choose an acceptable technique and its process parameters for the synthesis of magnesium-based metal matrix composites (MMCs). Additionally, it gives a general summary of how different reinforcements affect magnesium and its alloys, highlighting both their benefits and drawbacks.

Optimization of Filler Content and Size on Mechanical Performance of Graphene/Hemp/Epoxy-Based Hybrid Composites using Taguchi with ANN Technique

The usage of nanofillers in composite materials has grown over time due to various benefits, including superior properties, better adhesion, and high stiffness. To accomplish this, 150, 200, 250, and 300 gsm of hemp fiber mat with various thicknesses and weight proportions of graphene powder, including 0%, 3%, 6%, and 9%, as well as 3, 6, 18, and 25 µm-sized particles, were used. High-speed mechanical stirring was used to evenly mix the nanofiller (nanographene) with the epoxy-based nanocomposites at various loadings. We looked at the bending and interlaminar shear strength (ILSS) properties of hybrid nanomaterials. According to the study, adding 300 gsm of hemp epoxy composites filled with 6 wt% nanographene has significantly improved mechanical properties. The development of a forecasting model to determine the mechanical properties using artificial neural networks (ANN). The constructed model has a significant connection with the test findings. A correlation of 0.9724 for the Levenberg–Marquardt training procedure indicates a significant connection between the predicted and experimental artificial neural models. The observational and projected results for bending and ILSS have <3% and 4% errors, corresponding to the ANN prediction and Taguchi L16 matrix. The potential of ANN for forecasting the bending and ILSS of composite materials is expanded by the close relationship between ANN and experimental findings. The following parameters were used in the current study to determine the flexural strength: graphene content (40.79%), graphene size (34.19%), the number of hemp layers (12.57%), and hemp fiber thickness (11.65%). Similar to ILSS, graphene content accounts for 47.82% of the total, with graphene size (27.87%), hemp fiber thickness (11.80%), and the number of hemp layers (also 11.80%) all contributing (11.78%).

Machine Learning Approach for Prediction of Lateral Confinement Coefficient of CFRP-Wrapped RC Columns

Materials have a significant role in creating structures that are durable, valuable and possess symmetry engineering properties. Premium quality materials establish an exemplary environment for every situation. Among the composite materials in constructions, carbon fiber reinforced polymer (CFRP) is one of best materials which provides symmetric superior strength and stiffness to reinforced concrete structures. For the structure to be confining, the region jeopardizes seismic loads and axial force, specifically on columns, with limited proportion of ties or stirrups implemented to loftier ductility and brittleness. The failure and buckling of columns with CFRP has been studied by many researchers and is ongoing to determine ways columns can be retrofitted. This article symmetrically integrates two disciplines, specifically materials (CFRP) and computer application (machine learning). Technically, predicting the lateral confinement coefficient (Ks) for reinforced concrete columns in designs plays a vital role. Therefore, machine learning models like genetic programming (GP), minimax probability machine regression (MPMR) and deep neural networks (DNN) were utilized to determine the Ks value of CFRP-wrapped RC columns. In order to compute Ks value, parameters such as column width, length, corner radius, thickness of CFRP, compressive strength of the unconfined concrete and elastic modulus of CFRP act as stimulants. The adopted machine learning models utilized 293 datasets of square and rectangular RC columns for the prediction of Ks. Among the developed models, GP and MPMR provide encouraging performances with higher R values of 0.943 and 0.941; however, the statistical indices proved that the GP model outperforms other models with better precision (R2 = 0.89) and less errors (RMSE = 0.056 and NMBE = 0.001). Based on the evaluation of statistical indices, rank analysis was carried out, in which GP model secured more points and ranked top.

Ultralight and ultra-stiff nano-cardboard panels: Mechanical analysis, characterization, and design principles

We introduce a class of ultra-light and ultra-stiff sandwich panels designed for use in photophoretic levitation applications and investigate their mechanical behavior using both computational analyses and micro-mechanical testing. The sandwich panels consist of two face sheets connected with a core that consists of hollow cylindrical ligaments arranged in a honeycomb-based hexagonal pattern. Computational modeling shows that the panels have superior bending stiffness and buckling resistance compared to similar panels with a basketweave core, and that their behavior is well described by Uflyand-Mindlin plate theory. By optimizing the ratio of the face sheet thickness to the ligament wall thickness, panels maybe obtained that have a bending stiffness that is more than five orders of magnitude larger than that of a solid plate with the same area density. Using a scalable microfabrication process, we demonstrate that panels as large as 3 × 3 cm2 with a volumetric density of 20 kg/m3 and corresponding area density of 2 g/m2 can be made in a few hours. Micro-mechanical testing of the panels is performed by deflecting microfabricated cantilevered panels using a nanoindenter. The experimentally measured bending stiffness of the cantilevered panels is in very good agreement with the computational results, demonstrating exquisite control over the dimensions, form, and properties of the microfabricated panels.

Laser carbonization of lignin-based fiber membranes with heating treatment for flexible supercapacitors

Electrode materials significantly impact supercapacitor performance and developing high-performance electrode materials is crucial in energy storage. Commonly used laser-induced electrode materials are currently limited by severe contamination and hard-to-change intrinsic properties. This paper proposes a method for fabricating high-performance supercapacitors by laser carbonizing the lignin composite fiber membranes with heating treatment. Lignin fiber can achieve superior tensile strength, stiffness, and carbonization degree under suitable heat treatment temperatures. Heat treatment at 450 °C has been proven to be the ideal temperature for supercapacitor performance. At a current density of 1 A/g, the supercapacitor can reach the highest specific capacitance of ∼391.2F/g. In addition, doping MoS2 boosted the device's performance to a specific capacitance of ∼527.8F/g, a power density of ∼500 W/kg, and an energy density of ∼73 Wh/kg at the same current density. In addition, lignin fibers are ideal materials in electronic textiles due to their soft, thin, and breathable properties. This study provides supportive evidence and technical guidance for improving the performance of flexible wearable supercapacitors.

Uni-axial behaviour of steel slag concrete-filled-steel-tube columns with external confinement

Using steel slag, a waste by-product in the steel industry to replace natural aggregates to produce concrete can offer a sustainable solution in mitigating the environmental problems due to huge depletion of natural aggregates and disposal of abundant slag. Extensive research studies revealed that steel slag concrete has superior strength and stiffness but may also cause unsoundness to concrete. To solve the problem, steel slag concrete-filled-steel-tube (SSCFST) column was proposed, in which the concrete’s expansion would activate larger confining stress, and thereby enhancing the overall behaviour of the column. A total of 18 traditional concrete-filled-steel-tube (CFST) and SSCFST column specimens with and without external confinement were prepared and tested under uni-axial compression. The major testing parameters were the steel tube diameter to thickness ratio, steel slag coarse/fine aggregate replacement ratio and spacing of external confinement. Results revealed that by replacing 50% natural coarse aggregate with steel slag coarse aggregate or 50% natural fine aggregate with steel slag fine aggregate, the compressive strength of steel slag concrete increased but the flowability decreased. Besides, SSCFST columns showed superior mechanical behaviour than traditional CFST columns. With external confinement, the strength and stiffness were further improved. Lastly, a load–strain model developed previously by the authors was adopted to predict the mechanical behaviour of traditional CFST and SSCFST columns. Good agreement has been obtained between predicted and experimental results for traditional CFST column while for SSCFST columns, the model under-estimated the axial load and over-estimated the absolute hoop strain at a given axial strain attributed to the change in the packing structure and possible expansion of steel slag concrete.

Distinctive study on banana/sisal fiber hybrid composites filled with nano marble dust particles

The increased popularity of synthetic fibers has been hampered by high production costs and environmental concerns, despite the former's superior stiffness and strength. As a result, it's reasonable to consider devoting considerable effort to finding natural fibers that can replace synthetic ones in various applications. Because they have superior mechanical and thermal qualities over synthetic fibers, hybrid fibers are typically preferred. Natural fibers have the advantage of being more pliable and robust, but they cannot repel water. Most of the earlier research findings are very limited in determining the effects of marble dust particle addition on the two different types of natural fiber-reinforced epoxy composites. This experimental research work has incorporated a novel approach to fill this gap. Researchers have invented novel materials that could reduce the usage of thermoplastics to reduce the environmental issue. Cross-linking bond ability enhancement between the matrix and fiber has been done by adding nano marble dust particles. Short banana and sisal fibers (1 to 2 cm in length) are combined via injection molding with a polypropylene matrix to fabricate a hybrid composite with Nano marble dust particles (50 to 60 nm). The composites' flexural strength, impact strength, thermal conductivity, and water absorption enhance by adding Nano marble dust particles as filler material. It notices that banana and sisal fiber added composite contributed better tensile properties than Nano marble dust particles added composites.

Mechanical response of diaphragm wall supporting deep launch shaft induced by braced excavation and pipe jacking operation

The stability of braced structures for the launch pit in pipe jacking plays a vital role in structural safety during excavation and jacking drive. Through a deep launch pit in Foshan, the real-time deformation and mechanical response of the diaphragm walls, internal struts, and the soil behind the wall induced by braced excavation and pipe jacking operation are obtained from in-situ monitoring and three-dimensional finite element model. The internal struts restrict the further wall deflection and earth pressure in the braced excavation, displaying the apparent time–space effect or corner effect of the limited-scale & deep launch pit. Moreover, pipe jacking operation influences the reaction wall within a certain zone, contributing to the apparent spatial effect. The outward deformation and the increase in the soil pressure occurred in the disturbed zone. Although part of the mucky soil reaches the ultimate equilibrium during the deep excavation and jacking drive, the diaphragm walls still indicate superior strength and stiffness.

Preventing varus collapse in proximal humerus fracture fixation: 90-90 dual plating versus endosteal fibular allograft strut.

Screw cut out and varus collapse arethe most common complication of locked plate fixation of proximal humerus fractures. The purpose of this study was to compare dual plating and endosteal fibular allograft struts as augmentation strategies to prevent varus collapse. A trapezoidal osteotomy was created at the metaphysis to create a 2-part proximal humerus model in 18 paired shoulder specimens. Each specimen was assigned to group A, B, or C and was fixed with either a lateral locking plate, a lateral locking plate and anterior one-third tubular plate in an orthogonal 90/90 configuration, or a lateral locking plate with intramedullary fibular strut, respectively. The specimens were stressed in axial compression to failure. Displacement, elastic limit, ultimate load, and stiffness were recorded and calculated. There was no difference in mean cyclic displacement between the three groups (0.71mm vs 0.89mm vs 0.61mm for Group A, B, C, respectively). Lateral plating demonstrated the greatest absolute and relative displacement at the elastic limit (5.3mm ± 1.5 and 4.4mm ± 1.3) without significance. The elastic limit or yield point was greatest for fibular allograft, Group C (1223N ± 501 vs 1048N ± 367 for Group B and 951N ± 249 for Group A) without significance. Dual plating of proximal humerus fractures in a 90-90 configuration demonstrates similar biomechanical properties as endosteal fibular strut allograft. Both strategies demonstrate superior stiffness to isolated lateral locked plating.

Seismic performance of self-centering hybrid coupled wall systems: Preliminary assessments

Hybrid Coupled Wall (HCW) systems consist of reinforced concrete walls connected with steel coupling beams. HCWs benefit from the superior lateral stiffness of the reinforced concrete walls, while the coupling mechanism reduces the moment demand at the base of the walls. The present study investigates the seismic performance of a new HCW system equipped with friction-damped self-centering coupling beams and examines the efficiency of the new system in reducing residual deformations. The coupling beams of the intended HCW system consist of self-centering links, which can be easily repaired after severe earthquake events. The self-centering system utilized in this study features the following advantages distinguish it from conventional self-centering solutions: (i) it eliminates the coupling beams elongation problem (ii) it facilitates the application of pre-fabricated self-centering components to mitigate uncertainties raised by post-tensioning the connections on site. In this paper, the seismic behavior of the proposed lateral load-bearing system is investigated under several ground motion records and intensities. It is demonstrated that the applied self-centering mechanism has the capacity to minimize earthquake-induced residual deformations and repair time without increasing the damage level expected for the concrete walls in conventional HCWs.

An Improved Method of Synthesis of Graphene Oxide(GO) and Reduced Graphene Oxide(rGO) Nanocomposites

The oxidation and exfoliation of graphitized carbon was successfully achieved using modified Hummer’s method. Graphene is a remarkable material, electrical, thermal and barrier properties, graphene–based nanocomposites have been area of research in the past decade. Graphene possesses a large number of materials parameters such as superior mechanical stiffness, strength and elasticity, very high electrical and thermal conductivity. The synthesis and physical properties of graphene oxide and reduced graphene oxide (GO-rGO) Nanocomposite. The GO-rGO Nanocomposite was prepared by a modified Hummer’s method and then reduced using hydrazine hydrate (reducing agent) to produce rGO.XRD spectrum reveal that crystalline structure for both GO and rGO. The d-spacing is observed to be reduced for rGO as compared to that for GO because of removal of oxygen containing functional groups. The optical property was analysed using UV-vis Visible and photoluminences(PL) spectroscopy.