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Development of Fracture and Damage Modeling Concepts for Composite Materials
Published in Jayantha Ananda Epaarachchi, Gayan Chanaka Kahandawa, Structural Health Monitoring Technologies and Next-Generation Smart Composite Structures, 2016
Ayad Arab Ghaidan Kakei, Jayantha Ananda Epaarachchi, M. Mainul Islam, Jinsong Leng
Veer Singh and Talreja (2010) studied the off-axis ply cracks in multidirectional composite materials laminated under a quasistatic tensile in the longitudinal direction as shown in Figure 9.23. The study was based on the energy-based approach for off-axis ply cracks. The laminated energy parameters such as the energy release rate and arbitrary constants for crack tip were found from experimental methods. The 3D finite element analysis was used to calculate crack surface displacements (CSDs) because this model deals with off-axis cracks in multidirectional composite materials. An RVE that was a suitable 3D element to calculate the CSD is shown in Figure 9.24. It was assumed that a new crack appears between nearby cracks when maximum normal stress between them reaches to a critical strength value. The criterion for the formation new cracks was given as () W2N→N≥NWC1sinθtθ
Macromechanics of a Lamina
Published in Manoj Kumar Buragohain, Composite Structures, 2017
Pictorial representation of variation of the engineering constants with ply angle is helpful in the study of the effect of ply angle on the off-axis engineering constants. The example below is provided to present plots of variation of engineering constants with ply angle for carbon/epoxy and glass/epoxy laminae.
Elasticity and Strength of Laminates
Published in Ever J. Barbero, ®, 2013
The thickness of the drop-off is 0.75 × 2 = 1.5 mm. With a ply drop-off ratio 1:20, the length of the ply drop-off is 1.5 × 20 = 30 mm. Every 30 mm there is a section change. The bottom lamina is designated as lamina #1, and additional laminas are stacked from bottom to top in the positive normal direction of the element coordinate system. The APDL code is shown below and also available in [5, FEAcomp_Ex305.inp]. /TITLE,Tape with Ply Drop-off between [90/0]s and [90/0] ! Material is AS4D/9310 - Th=0.75 mm per lamina - SHELL181 /UNITS,MPA ! Units are in mm, MPa, and Newtons /PREP7 ! Pre-processor module ! Material properties FOR AS4D/9310 orthotropic laminate UIMP,1,EX,EY,EZ,133.86E3,7.706E3,7.706E3 UIMP,1,GXY,GYZ,GXZ,4.306E3,2.76E3,4.306E3 UIMP,1,PRXY,PRYZ,PRXZ, 0.301,0.396,0.301 ET,1,SHELL181 ! Chooses SHELL181 element for analysis KEYOPT,1,3,2 ! Set KEYOPT(3)=2, Full integration ! (recommended for SHELL181/composites) SECTYPE,1,SHELL,,A ! Section shell set #1, [90/0]s, A SECDATA, 0.75,1,90,3 ! 1st lamina: mat. #1, 90 deg, Th=0.75 mm SECDATA, 0.75,1,0,3 ! 2nd lamina: mat. #1, 0 deg, Th=0.75 mm SECDATA, 0.75,1,0,3 ! 3rd lamina: mat. #1, 0 deg, Th=0.75 mm SECDATA, 0.75,1,90,3 ! 4th lamina: mat. #1, 90 deg, Th=0.75 mm SECOFFSET,BOT ! Nodes on the laminate BOTTOM thickness SECTYPE,2,SHELL,,DROP ! Section shell set #2, [90/0/0], DROP SECDATA, 0.75,1,90,3 ! 1st lamina: mat. #1, 90 deg, Th=0.75 mm SECDATA, 0.75,1,0,3 ! 2nd lamina: mat. #1, 0 deg, Th=0.75 mm SECDATA, 0.75,1,0,3 ! 3rd lamina: mat. #1, 0 deg, Th=0.75 mm SECOFFSET,BOT ! Nodes on the laminate BOTTOM thickness SECTYPE,3,SHELL,,B ! Section shell set #2, [90/0], B SECDATA, 0.75,1,90,3 ! 1st lamina: mat. #1, 90 deg, Th=0.75 mm SECDATA, 0.75,1,0,3 ! 2nd lamina: mat. #1, 0 deg, Th=0.75 mm SECOFFSET,BOT ! Nodes on the laminate BOTTOM thickness ! Geometry and mesh RECTNG, 0,60,0,50 ! Laminate A x=60 mm and y=50 mm RECTNG,60,(60+30),0,50 ! Laminate Drop x=15 mm and y=50 mm RECTNG,(60+30),(120),0,50 ! Laminate B x=60 m and y=50 mm AGLUE,all ! Glue all areas ESIZE,5 ! Element size 5 mm SECNUM, 1 AMESH,1 ! Mesh the area number 1 SECNUM, 2 AMESH,4 ! Mesh the area number 2 SECNUM, 3 AMESH,5 ! Mesh the area number 3 FINISH ! Exit pre-processor module /SOLU ! Solution module ANTYPE,STATIC ! Set static analysis DL,4,1,all,0 ! Impose clamped BC DL,1,1,symm ! Impose Symmetry BC DL,13,4,symm DL,15,5,symm SFL, 10,PRES,−10 ! Apply uniform pressure in N/mm SOLVE ! Solve current load state FINISH ! Exit solution module /POST1 ! Post-processor module PLDISP,1 ! Display the deformed plate FINISH ! Exit post-processor module
A meshfree method for free vibration analysis of ply drop-off laminated rectangular plates
Published in Mechanics of Advanced Materials and Structures, 2022
Songhun Kwak, Kwanghun Kim, Yonghua Li, Cholho Pang
In this paper, a TRIPM shape function is proposed that uses a new basis that combines the highly accurate and stable Tchebychev polynomial basis and the radial basis. Tchebychev polynomials are chosen because they are identified as having superior convergence characteristics, numerical stability, and accuracy in solving free vibration problems [42–44]. Tchebychev polynomials have been shown to be superior in handling the boundary conditions [45]. Recently, studies have been conducted for the dynamical analysis of various structures using the Tchebychev polynomial approach [46, 47]. The proposed TRPIM shape function is applied to the displacement approximation of ply drop-off laminated plates. First, the ply drop-off laminated plate is decomposed into several substructures without drop-off plies, and the governing equations and boundary conditions of the substructures are derived using FSDT and Hamilton's principle. In these equations, the displacement components are approximated by the meshfree TRIPM shape function to obtain discrete algebraic equations for individual substructures. Next, the natural frequencies and mode shapes of the ply drop-off laminated plate are obtained by solving the equations of the entire system derived using the continuous conditions of the displacements in the combination region between the substructures. Through various numerical examples, the effect of parameters such as material property, geometric dimension, and laminate structure on the free vibration of ply drop-off laminated plate is investigated.
Cost-benefit model in improving traceability system: case study in Indonesian bulk-liquid industry
Published in Supply Chain Forum: An International Journal, 2019
Ivan Gunawan, Iwan Vanany, Erwin Widodo
System dynamics (SD) has been widely used for cost system modelling such as to see cost factors that affect quality cost (Kiani et al. 2009) and to find a trade-off between service quality and cost (Kim and Wook Kim 2010). SD was considered as an appropriate modelling method for building cost-benefit models because it can accommodate a complicated relationship between variables and time-dependent behaviour better than mathematical modelling (Sterman 2000). There were two stages in constructing the cost-benefit model before running the simulation. First, a causal loop diagram (CLD) was formulated. The CLD was then translated into a Stock Flow Diagram (SFD). The most extreme single case was simulated using STELLA 9.13 to explore the trade-off between the cost and the benefit of each improvement scenario. Finally, the results were compared using a cost-benefit ratio.
An efficient workflow for meshing large scale discrete fracture networks for solving subsurface flow problems
Published in Petroleum Science and Technology, 2022
In user layer, all modules related to viewer are included. The DFNViewer is most important as it contains all UI code and OpenGL graphics window which renders DFN entities and mesh. All GUI components are included into this project. CCTechDatabase is used to store data related to display entity. To support loading of all other geometry files (such as STL, OFF, GNU etc.), we created different translator projects (such as STLTranslator, OFFTranslator, and GNUTranslator) to read specific files and store data into a database.