Multiscale Modeling of a Notched Coupon Test for Triaxially Braided Composites

2019 ◽  
Vol 795 ◽  
pp. 172-179
Author(s):  
Yan Qi Hu ◽  
Wieslaw K. Binienda
Keyword(s):  
Multiscale Modeling ◽  
Large Scale ◽  
Laminated Composite ◽  
High Strength ◽  
Multiscale Model ◽  
Tensile Tests ◽  
Local Deformation ◽  
Modeling Method ◽  
Braided Composites ◽  
Element Analysis

Braided composites have been widely used in aerospace and automotive structures due to their light weight and high strength. Unlike metal or laminated composite material, the complex braided structure brings a lot of challenges when conducting numerical simulation. In this paper, a finite element analysis based meso-mechanical modeling for the two dimensional triaxially braided composite was developed. This mesoscale modeling method is capable of considering the detailed braiding geometry and architecture as well as the mechanical behavior of fiber tows, matrix and the fiber tow interface. Furthermore, a multiscale model combined both macroscale and mesoscale approaches and it is realized within LS-DYNA environment through Interface_components and Interface_linking. This combined multiscale modeling approach enables the full advantage of both the macroscale and mesoscale approaches, which can describe the details of local deformation and the global overall response features of the entire structure with the minimum computational expense. The evaluation and verification of the mesoscale approach and combined multiscale modeling method is through a notched coupon tensile tests conducted by Kohlman in both axial and transverse direction. The multiscale modeling method captures the response feature accurately so it has the ability to analyze large scale structures.

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. 

Structural Design Capacity of X120 Linepipe

2004 ◽  
Author(s):  
Karel Minnaar ◽  
Brian W. Duffy ◽  
Erlend Olso ◽  
Scott D. Papka ◽  
Michael M. Zhang
Keyword(s):  
Structural Design ◽  
Large Scale ◽  
High Strength ◽  
External Pressure ◽  
Experimental Program ◽  
Element Analysis ◽  
Parametric Studies ◽  
Sensitivity Studies ◽  
Bending Loads ◽  
Grade Material

A new high strength steel linepipe with a specified minimum yield strength of 120 ksi (X120) has recently been introduced to industry. The newly developed linepipe meets all mechanical property targets of an X120 grade material as verified through an extensive small and large-scale experimental program. Design equations have been developed and verified with full scale testing that allow pipeline designs that take full economic advantage of the higher strength of X120. This paper focuses on the development and verification of capacity equations for bending loads, external pressure (collapse) loads, combined bending and external pressure loads, and internal pressure (burst) loads. The corresponding response of the pipe was investigated with finite element analysis (FEA). Analytical equations that predict the burst, bending, and collapse capacities were then established based on parametric studies performed using FEA models. To gain confidence in the models, full size pipe tests were conducted and the results compared to FEA. The testing demonstrated that the FEA models accurately predict the behavior of the X120 pipe. Modifications to the existing equations were made when necessary to ensure the capacity equations correctly capture the pipe response for higher D/t ratios and for the higher strength X120 material. Material sensitivity studies show that the new equations accurately predict the X120 behavior over the range of load conditions evaluated.

Numerical Modelling of the Experimental Response of SRG Systems

2019 ◽  
Vol 817 ◽  
pp. 37-43
Author(s):  
Marialaura Malena ◽  
Marialuigia Sangirardi ◽  
Francesca Roscini ◽  
Gianmarco de Felice
Keyword(s):  
Numerical Modelling ◽  
Large Scale ◽  
Numerical Models ◽  
High Strength ◽  
Experimental Tests ◽  
Tensile Tests ◽  
Technical Committee ◽  
Structural Performance ◽  
Rilem Technical Committee ◽  
Test Procedures

Modern repairing and retrofitting methods for existing structures make use of composite materials, consisting of high strength textiles and a matrix, which can be either polymeric or inorganic. These kinds of techniques have been largely applied to masonry structures, since they significantly improve structural performance with a small increase of weight and a minimum invasiveness. However, the application of organic gluing agents on masonry has revealed some well-known drawbacks, which are almost all overcome resorting to inorganic matrixes, namely cement or lime mortars. An entire class of composites is thus identified as TRM (Textile Reinforced Mortars) or FRCM (Fibre Reinforced Cementitious Matrices). Among them, Steel Reinforced Grout (SRG) are characterized by Ultra High Tensile Strength Steel (UHTSS) cords embedded in mortar matrix and their use to improve the structural performance of existing historical masonry buildings is becoming more and more diffused. Qualification tests and acceptance criteria for SRG have just been defined. Nonetheless, numerical simulation of current available test procedures is mandatory to identify peculiar aspects of the response that at a following stage become an integral part of large scale models, when entire reinforced structures or portions need to be analysed. To this end, this work presents the numerical modelling of two different direct tensile tests on SRG systems: the Clamping-grip setup (RILEM Technical Committee 232-TDT 2016) and the Clevis-grip setup (ICC-ES AC434 2016). Numerical models able to replicate experimental tests and catch fundamental differences in their failure mechanisms are present

Towards a Numerical Design Tool for Composite Crack Arrestors on High Pressure Gas Pipelines

2010 ◽  
Author(s):  
F. Van den Abeele ◽  
L. Amlung ◽  
M. Di Biagio ◽  
S. Zimmermann
Keyword(s):  
High Pressure ◽  
Large Scale ◽  
Steel Wire ◽  
Large Diameter ◽  
High Strength ◽  
Tensile Tests ◽  
Design Tool ◽  
Pipe Material ◽  
Gas Pipelines ◽  
Numerical Design

One of the major challenges in the design of ultra high grade (X100) high pressure gas pipelines is the identification of a reliable crack propagation strategy. Ductile fracture propagation is an event that involves the whole pipeline and all its components, including valves, fittings, flanges and bends. Recent research results have shown that the newly developed high strength large diameter gas pipelines, when operated at severe conditions (rich gas, low temperatures, high pressure), may not be able to arrest a running ductile crack through pipe material properties. Hence, the use of crack arrestors is required in the design of safe and reliable pipeline systems. A conventional crack arrestor can be a high toughness pipe insert, or a local joint with higher wall thickness. Steel wire wrappings, cast iron clamps or steel sleeves are commonly used non-integral solutions. Recently, composite crack arrestors have enjoyed increasing interest from the industry as a straightforward solution to stop running ductile cracks. A composite crack arrestor is made of (glass) fibres, dipped in a resin bath and wound onto the pipe wall in a variety of orientations. In this paper, the numerical design of composite crack arrestors will be presented. First, the properties of unidirectional glass fibre reinforced epoxy are measured and the micromechanic modelling of composite materials is addressed. Then, the in-use behaviour of pipe joints with composite crack arrestors is covered. Large-scale tensile tests and four point bending tests are performed and compared with finite element simulations. Subsequently, failure measures are introduced to predict the onset of composite material failure. At the end, the ability of composite crack arrestors to arrest a running fracture in a high pressure gas pipeline is assessed.

Short Transverse Properties of Certain High-Strength Steels

1968 ◽  
Vol 90 (4) ◽  
pp. 627-635 ◽  
Author(s):  
A. D. E. Thomson ◽  
P. R. Christopher ◽  
J. Bird
Keyword(s):  
Large Scale ◽  
Nonmetallic Inclusions ◽  
High Strength Steels ◽  
High Strength ◽  
Tensile Tests ◽  
Steel Plates ◽  
High Yield ◽  
Fatigue Properties ◽  
Short Transverse ◽  
Effect On Yield

Attention has been paid in Naval Construction Research Establishment to the importance of problems arising from the presence of small nonmetallic inclusions in high-strength, low-alloy structural steels and, in particular, to their effect on short transverse properties. Consequences can be more marked in high yield steels since, in general, these possess a higher yield to ultimate ratio and lower ductility in tensile tests than for mild steel. The nature of these inclusions and the value of the various tests carried out to determine their effects on the properties of steel plates are discussed. The consequences of short transverse weakness in large-scale construction employing thick plates is considered. Although there is no effect on yield strength it is clear that ductility and fatigue properties of such structures may need special attention. In general, measures recently imposed to obtain adequately inclusion-free steel are endorsed for current steels, but for projected steels of higher yield more sophisticated methods of manufacture may be necessary.

scholarly journals Natural Frequency for a Composite Structure Made with a Combination of Metal and Laminated Composites

2020 ◽  
Vol 8 (6) ◽  
pp. 2340-2344
Keyword(s):  
Modal Analysis ◽  
Natural Frequency ◽  
Composite Structure ◽  
Laminated Composite ◽  
High Strength ◽  
Element Analysis ◽  
Volume Percentage ◽  
Steam Turbine Blade ◽  
Laminated Composite Beam ◽  
Natural Frequency Analysis

The need for low weight and high strength of the component is in high demand in various aerospace and defense industries and in line with this utilization of the combination of metal and composite increases. In this work, the natural frequency analysis of the structure, is carried out which is a combination of metal and composite. The natural frequency of the system is directly proportional to the stiffness of the system i.e. high natural frequency reflects high stiffness of materials. The structure considered like a cantilever beam, initially considering Titanium alloy the finite element analysis to get natural frequency carried out and validated using an analytical method. Then modal analysis performed using FEA for laminated composite structure and validate with the experimental results and received good agreement. The laminated composite beam manufactured using a hand layup method. Lastly, the structure modeled as a combination of laminated composite material & metal and FEA modal analysis done. The various volume percentage of composite and metal is studied and the best one finds out. The structure considered related to the last stage of the steam turbine blade.

scholarly journals Investigation on the Tensile Behavior of Graphene-Aluminum Nano-Laminated Composites by Molecular Dynamics Simulation

2019 ◽  
Vol 804 ◽  
pp. 1-6
Author(s):  
Jia Qi Zhu ◽  
Qing Sheng Yang ◽  
Xia Liu
Keyword(s):  
Molecular Dynamics ◽  
Tensile Strength ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Laminated Composite ◽  
High Strength ◽  
Tensile Tests ◽  
Dynamics Simulation ◽  
Uniaxial Tensile ◽  
Al Composite

Graphene-aluminum (Gr/Al) composite laminated by aluminum (Al) and graphene sheets alternately has excellent mechanical properties thanks to the high strength, high Young’s modulus and the two-dimensional atomic structure of graphene. In this study, the uniaxial tensile properties of Gr/Al nano-laminated composite are studied by molecular dynamics (MD) method. It is found that the thickness of Al layer has a significant effect on the tensile strength and Yang’s modulus of the Gr/Al composite. Composite with a smaller thickness of Al layer shows better properties. Graphene not only block propagation of dislocations, but bear most of the loads, resulting in higher Young's modulus, tensile strength and failure strain of the composites than those of pure Al. The simulation of temperature-effect shows that the Gr/Al composite is difficult to arise plastic deformation at low temperature, which lead to a higher strength and modulus of the composite. In addition, the effect of graphene stacking on the properties of composites is investigated. Through tensile tests at the vertical and parallel interfaces, it is found that graphene stacking may lead to a reduced performance of the composite.

CNT Reinforced Laminated Composite under In-Plane Tensile Loading: A Finite Element Study

2020 ◽  
Vol 978 ◽  
pp. 323-329
Author(s):  
Krishnendu Bhowmik ◽  
Shamim Akhtar ◽  
Raj Kumar Kalshyan ◽  
Niloy Khutia ◽  
Amit Roy Choudhury
Keyword(s):  
Finite Element ◽  
Laminated Composite ◽  
Peak Stress ◽  
Transversely Isotropic ◽  
High Strength ◽  
Tensile Loading ◽  
Stiffened Panel ◽  
Element Analysis ◽  
Premature Failure ◽  
Wide Range

The present study is mainly aimed at investigating the distribution of in-plane stresses of a rectangular plate under localized uniform in-plane tensile loading through finite element analysis. The configuration used in the analysis is analogous to the case of premature failure of stiffened panel due to the termination of a stiffener in aircraft wing structure. In this current work, three different types of materials namely, isotropic, plain woven and transversely isotropic materials are being considered. Aluminium is taken as isotropic; high strength carbon/epoxy is being assigned as plain woven composite and carbon nanotube based hybrid composite is used as transversely isotropic material, due to their wide range of applications in aircraft structures. The effect of different materials on overall axial, transverse and shear stress distributions at different layers of the stiffened composite panels are demonstrated using finite element analyses. Further, the variations of these stresses along axial and transverse directions are also compared for different materials. It can be concluded from the present study that the peak stress developed near the load application zone should be incorporated in the design criteria of such plates to avoid failure.

scholarly journals Method of Designing a Friction-Based Wedge Anchorage System for High-Strength CFRP Plates

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6443
Author(s):  
Wanxu Zhu ◽  
Wei Wei ◽  
Fengrong Liu ◽  
Rong Zeng
Keyword(s):  
Plate Thickness ◽  
High Strength ◽  
Tensile Tests ◽  
Conical Surface ◽  
Minimum Length ◽  
Efficiency Coefficient ◽  
Element Analysis ◽  
Cfrp Plate ◽  
Anchorage System ◽  
Dip Angle

The cables of high-strength carbon fiber reinforced polymer (CFRP) plates are starting to be applied to large spatial structures. However, their main anchorage systems rely on the adhesive force, which entails risks to their integrity resulting from aging of the binding agent. In this study, a friction-based wedge anchorage system was designed for CFRP plates. The working mechanism of the proposed anchorage system was explored both theoretically and experimentally. The anti-slip mechanism and condition of CFRP plates were formulated so that the equivalent frictional angle of the contact surface between a CFRP plate and wedges must not be smaller than the sum of the dip angle of the wedge external conical surface and the frictional angle between the wedges and barrel. An analysis of the stress distribution in the anchorage zone of the CFRP plate was conducted using the Tsai-Wu failure criterion, which concluded that the compressive stresses should be reduced on the section closer to the load-bearing end of the anchorage system. Furthermore, the anchorage efficiency coefficient was proposed, which depends on stress concentration coefficients, plate thickness, length of anchorage zone, dip angle of wedge external conical surface, and its frictional angle. Then, it was determined that the minimum length of an anchorage zone for the CFRP plates with various specifications should be at least 49 times larger than the CFRP thickness. A finite element analysis and static tensile tests on six specimens were carried out. The experimental results revealed that the anchorage efficiency coefficient of the optimized anchor reached 97.9%.

Stiffness Evaluation of an Adsorption Robot for Large-scale Structural Parts Processing

2021 ◽  
pp. 1-14
Author(s):  
Jiakai Chen ◽  
Fugui Xie ◽  
Xin-Jun Liu ◽  
Weiyao Bi
Keyword(s):  
Large Scale ◽  
Parallel Robots ◽  
Modeling Method ◽  
Machining Process ◽  
Element Analysis ◽  
Stiffness Modeling ◽  
Stiffness Evaluation ◽  
Machining Robot ◽  
Structural Parts ◽  
Five Axis

Abstract Efficient and economical processing of large-scale structural parts is in increasing need and is also a challenging issue. In this paper, an adsorption machining robot for processing of large-scale structural parts is presented. It has potential advantages in flexible, efficient and economical processing of large-scale structural parts because of the adsorption ability. Stiffness is one of the most important performance for machining robots. In order to investigate the stiffness of the robot in the workspace, the kinematics of the adsorption manipulator, the five-axis machining manipulator and the adsorption machining robot is derived step by step. Then with the help of Finite Element Analysis (FEA), a stiffness modeling method considering the compliance of the base is proposed. A stiffness isotropy index is put forward to evaluate the robot's overall stiffness performance by taking all possible working conditions into consideration. Based on the index, stiffness evaluation in the reachable workspace is carried out and an optimized workspace is identified considering the overall stiffness magnitude, stiffness isotropy and workspace volume, which will be used in the machining process. The stiffness modeling method and stiffness isotropy index proposed in the paper are universal and can be applied to other parallel robots.

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