Stiffness Analysis of Delaminated Composite Beams Using Roller Clamps

2021 ◽  
Author(s):  
P. G. Vivek ◽  
Ankuran Saha ◽  
Apurba Das ◽  
Kazuaki Inaba ◽  
Amit Karmakar
Keyword(s):  
Free Vibration ◽  
Composite Beam ◽  
Composite Structures ◽  
Structural Parameters ◽  
Weight Ratio ◽  
Laminated Composite ◽  
High Strength ◽  
Simulation Software ◽  
Complex Activity ◽  
Aerospace Applications

Abstract Composites are favored over other traditional materials in many aerospace applications because of their high stiffness and strength-to-weight ratio. Taylor made material properties can be achieved by scheming the structural parameters making the material light, high strength and durable. Present work deals with a novel approach to enhance the strength of a layered delaminated composite beam using roller clamps to improve stiffness by providing uniform transverse force. Composite beam stiffness significantly degrades due to adverse environmental condition, impact loading and delamination effect. Composite structures are prone to delamination during its life span. Therefore in depth knowledge is needed to find the effect of roller clamps on the dynamic behavior of beam with varying delamination sizes. Present approach will be useful to enhance the stiffness of composite structure with delamination. The free vibration of a clamped cantilever beam is investigated, and the results are compared to those of an unclamped and undelaminated beam. The findings are supported by experimentally obtained responses (modal analysis). Furthermore, the complex activity of the laminated structure is numerically computed and the obtained data is compared to those available in open literature to ensure correctness. The laminated composite beam’s static and free vibration responses are calculated using finite element simulation software (ANSYS).

Tensile Properties of Angle Cured Laminated Composites Structures under Gravity Effects

2013 ◽  
Vol 465-466 ◽  
pp. 101-105
Author(s):  
Mohd Yuhazri bin Yaakob ◽  
T.T.T. Jennise ◽  
H. Sihombing ◽  
Md Radzai bin Said ◽  
U. Nirmal ◽  
...  
Keyword(s):  
Tensile Properties ◽  
Composite Structures ◽  
Weight Ratio ◽  
Laminated Composite ◽  
High Strength ◽  
Maximum Force ◽  
Composites Materials ◽  
Laminated Composite Structures ◽  
Gravity Effects ◽  
Optimum Productivity

As the usage of composites materials are significant in the industries of automobiles, shipping and constructions due to their non-corrosive and high strength to weight ratio. Anyway, the production of composites needed to be increased to meet the demand. At this stage, problem faced by Small and Medium Industries / Entrepreneurs (SMI/E) is the confined and limited space available that restricts the optimum productivity. They commonly cure the composites horizontally that requires ample space and unable to afford for high-end equipment such as mechanical oven and autoclave in the production as a result of high capital cost.This research is carried out to study the feasibility of the gravity effects on curing position of the laminated composite structures to enhance the curing space needed. The aim of the research was to investigate the tensile properties of the thermosetting laminated composite by curing the laminate at different angle using vacuum bagging technique. From the testing, SN 5 which denominated to be 60 ̊ found to have the best tensile properties in term of maximum force exerted and Youngs modulus.

SANDVIK Ti-3Al-2.5V GRADE 9

Alloy Digest ◽  
1997 ◽  
Vol 46 (9) ◽  
Keyword(s):  
Corrosion Resistance ◽  
Endurance Limit ◽  
Weight Ratio ◽  
High Strength ◽  
Strain Ratio ◽  
Bend Strength ◽  
Aerospace Applications ◽  
Excellent Corrosion Resistance ◽  
Titanium Aluminum ◽  
Fatigue Endurance

Abstract Sandvik Ti-3Al-2.5V Grade 9 titanium-aluminum alloy offers excellent corrosion resistance, especially to chloride media, and has a high strength-to-weight ratio, which is especially suitable for use in aerospace applications. Tubing can be produced having a CSR (contractile strain ratio) that enhances the fatigue endurance limit. This datasheet provides information on composition, physical properties, elasticity, tensile properties, and bend strength as well as fatigue. It also includes information on corrosion resistance as well as forming, machining, and joining. Filing Code: TI-109. Producer or source: Sandvik.

PROGRESSIVE DAMAGE FAILURE ANALYSIS OF POST-BUCKLED COMPOSITE SINGLE-STRINGER PANEL WITH TEFLON INSERTS

2021 ◽  
Author(s):  
VIJAY K. GOYAL ◽  
AUSTIN PENNINGTON ◽  
JASON ACTION
Keyword(s):  
Experimental Data ◽  
Composite Structures ◽  
Laminated Composites ◽  
Compressive Loading ◽  
Weight Ratio ◽  
High Strength ◽  
Material Model ◽  
Stiffened Panels ◽  
Damage Initiation ◽  
Critical Aspects

The high strength-to-weight and stiffness-to-weight ratio materials, such as laminated composites, are advantageous for modern aircraft. Laminated composites with initial flaws are susceptible to delamination under buckling loads. PDA tools help enhance the industry’s understanding of the mechanisms for damage initiation and growth in composite structures while assisting in the design, analysis, and sustainment methods of these composite structures. The global-local modeling approach for the single-stringer post-buckled panel was evaluated through this effort, using Teflon inserts to simulate the defect of damage during manufacturing. This understanding is essential for designing the post-buckled structure, reducing weight while predicting damage initiation location, and addressing a potential design review for future aircraft repairs. In this work, the initial damage was captured with Teflon inserts as the starting configuration; and any reference to the damage initiation refers to any damage beyond the “initial unbonded region.” The effort aims to develop, evaluate, and enhance methods to predict damage initiation and progression and the failure of post-buckled hat-stiffened panels using multiple Abaqus FEA Virtual Crack Closure Technique (VCCT) definitions. Validation of the PDA using the VCCT material model was performed on a large single-stringer panel subjected to compressive loading. The compressive loading of the panel caused the skin to buckle before any damage began to occur locally. In addition, comparisons are made for critical aspects of the damage morphology, such as a growth pattern that included delamination from the skin-stiffener interface to the skin and ply interfaces. When compared against the experimental data produced through the NASA Advanced Composites Project (ACP), the present model captured damage migration from one surface to another, and model validations were ~5% of the experimental data.

scholarly journals Geometrical behavior of laminated graphite/epoxy composite using hypermesh

2018 ◽  
Vol 7 (2.20) ◽  
pp. 214
Author(s):  
Ch Siva RamaKrishna ◽  
KV Subba Rao ◽  
Saineelkamal Arji
Keyword(s):  
Residual Stresses ◽  
Epoxy Composite ◽  
Weight Ratio ◽  
Laminated Composite ◽  
High Strength ◽  
Element Analysis ◽  
Aspect Ratios ◽  
Military Applications ◽  
Inherent Strength

The laminated composite material is  made of ply which are specically used in automotive, aerospace and military applications due to less in weight and high strength to weight ratio. The role of structural strength is very important in composites, as the material is weak in inherent strength leads to damage of equipment made with the laminated composite. Hence, an accurate understanding of their structural geometrical behavior for residual stresses is required, such as residual stresses with different aspect ratios. In present work, various aspect ratios of laminated composite and its residual stresses are investigated using finite element analysis. The numerical results showed, on the residual stresses, that the effects the change the residual stresses due change of aspect ratio of laminated Graphite/epoxy composite. 

scholarly journals Damage Characterization of Nano-Interleaved CFRP under Static and Fatigue Loading

Fibers ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 13 ◽  
Author(s):  
Mohamad Fotouhi ◽  
Cristiano Fragassa ◽  
Sakineh Fotouhi ◽  
Hamed Saghafi ◽  
Giangiacomo Minak
Keyword(s):  
Acoustic Emissions ◽  
Weight Ratio ◽  
Laminated Composite ◽  
High Strength ◽  
Fatigue Loading ◽  
Fatigue Tests ◽  
Limiting Factor ◽  
Delamination Toughness ◽  
Delamination Resistance ◽  
Laminated Composite Materials

The use of high strength-to-weight ratio-laminated fiber-reinforced composites is emerging in engineering sectors such as aerospace, marine and automotive to improve productivity. Nevertheless, delamination between the layers is a limiting factor for the wider application of laminated composites, as it reduces the stiffness and strengths of the structure. Previous studies have proven that ply interface nanofibrous fiber reinforcement has an effective influence on delamination resistance of laminated composite materials. This paper aims to investigate the effect of nanofiber ply interface reinforcement on mode I properties and failure responses when being subjected to static and fatigue loadings. For this purpose, virgin and nanomodified woven laminates were subjected to Double Cantilever Beam (DCB) experiments. Static and fatigue tests were performed in accordance with standards and the Acoustic Emissions (AE) were acquired during these tests. The results showed not only a 130% increase of delamination toughness for nanomodified specimens in the case of static loads, but also a relevant crack growth resistance in the case of fatigue loads. In addition, the AE permitted to relate these improvements to the different failure mechanisms occurring.

Tolerance Simulation of Thin-Walled C-Section Composite Beam in Wingbox Assembly Under Preloading

2015 ◽  
Author(s):  
Hua Wang ◽  
Jun Liu
Keyword(s):  
Probability Distribution ◽  
Composite Beam ◽  
Composite Structures ◽  
Simulation Method ◽  
Simulation Software ◽  
Fea Model ◽  
Final Assembly ◽  
Thin Walled ◽  
Thickness Variations ◽  
Induced Changes

Tolerance simulation’s reliability depends on the concordance between the input probability distribution and the practical situation. Pre-loading induced changes in the probability distribution should be considered in the structure’s tolerance simulation, especially for composite structures. The paper presents a tolerance simulation method for the thin-walled C-section composite beam (TC2B) assembling under preloading, that is prescribed clamping force. Based on FEA model of TC2B, the preloading-modified probability distribution function of the R angle spring-in deviation is proposed. Thickness variations of the TC2B are obtained from the data of the downscaled composite wingbox. These parts’ variations are input to the tolerance simulation software, and the final assembly variations are obtained. The assembly of the downscaled wingbox illustrates the effect of preloading on the probability distribution of the R angle spring-in deviation. The results have shown that tolerance simulation with the modified probability distribution is more accurate than the initial normal distribution. The tolerance simulation work presented in the paper will enhance the understanding of the composite parts assembling with spring-in deviations, and help systematically improving the precision control efficiency in civil aircraft industry.

Vibration and Buckling Response of Width Tapered Laminated Composite Beams Using Ritz Method for Rotorcraft Blade

2010 ◽  
Author(s):  
Vijay Kumar Badagi ◽  
Rajamohan Ganesan
Keyword(s):  
Free Vibration ◽  
Boundary Conditions ◽  
Composite Beam ◽  
Ritz Method ◽  
Compressive Force ◽  
Laminated Composite ◽  
Free Vibration Analysis ◽  
Composite Beams ◽  
Buckling Analysis ◽  
Laminated Composite Beam

In this study, Symmetric cross-ply linear width tapered laminated composite beam is considered. Due to the variety of width tapered composite beams and the complexity of the analysis, no closed-form analytical solution is available at present regarding free vibration response. Therefore in the present work, the Ritz method is used for the free vibration analysis with considering uni-axial compressive and tensile force. The elastic stiffness of the width tapered composite beam is analyzed compared to uniform laminated composite beam. Free vibration which is significant to investigate the dynamic characteristics of the structure using Ritz method with and without effect of axial tensile and compressive force is analyzed. The analysis is based on 1D laminated beam theory. The governing equations are obtained by means of Hamilton’s principle. Tsai-Wu failure analysis is considered to find the tensile and compressive failure force for each ply in the laminate. Buckling analysis is conducted to find the critical buckling force for the laminated composite beam-column subjected to different sets of boundary conditions. Simply supported, Clamped-free, Clamped-Clamped edge boundary conditions are considered. A detailed parametric study is conducted on tapered composite beams made of NCT/301 graphite-epoxy to investigate the effects of the ratio of the width of the thick section to thin section, boundary conditions, effects of axial and compressive force on natural frequency and buckling analysis.

scholarly journals A Review Of Mechanisms And Fracture Mechanics Of Moisture Ingress In Composite Systems

2021 ◽  
Author(s):  
Janani S. Gopu
Keyword(s):  
Fracture Mechanics ◽  
Composite Structures ◽  
Composite System ◽  
Aerospace Industry ◽  
Weight Ratio ◽  
High Strength ◽  
Honeycomb Structure ◽  
Sandwich Composite ◽  
Composite Systems ◽  
Water Accumulation

Composite materials help realize high strength to weight ratio requirements of the Aerospace Industry. Composite structures and sandwich composite structures are susceptible to moisture ingress. Moisture ingress causes degradation of thermo-mechanical properties of the composite panels. Water accumulation in sandwich composite structures causes rapid degradation of face to core bondline, damage of cells frozen water and even blow off skins owing to sudden pressure build up in the cells of the honeycomb structure. Mechanisms of moisture ingress can be broadly classified into direct and indirect mechanisms. Direct ingress occurs through pre-existing pathways formed by defects in the composite system. Indirect mechanisms are diffusion, Capillary actions, Wicking actions, and Osmosis. The first form of damage in FRP materials is microcracking. The rate of microcracking increases with moisture ingress. Microcracking fracture toughness is a material property for the susceptibility of a composite system to the formation of microcracks. This work implores the mechanisms and the fracture mechanics dominating the formation of microcracks.

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