In this numerical code, the shear nonlinearity and failure behavior of #composite laminates were investigated with experimental and #numericalanalysis .
A nonlinear shear model that includes progressive stiffness reduction and shear strain was developed to characterize the nonlinear shear behavior.
Stress-based 3D Hashin #failurecriteria were combined with a set of stiffness degradation method to predict in-ply damage initiation and evolution of composite laminates.
The progressive damage model was implemented in commercial finite element software #ABAQUS by a #USDFLD #subroutine.
The capability of the proposed model was validated by predicting four different samples:
1- Open-hole compression specimen test,
2- Simple plate tension test [+-45],
3- Open-hole tension specimen test with [+-30]2s layup and
4- Open hole tensile specimen test with [+-35/0/90]s layup.
learn more https://en.banumusagr.com/shop/3d-hashin-failure-criteria-usdfld-subroutine-for-abaqus/
A nonlinear shear model that includes progressive stiffness reduction and shear strain was developed to characterize the nonlinear shear behavior.
Stress-based 3D Hashin #failurecriteria were combined with a set of stiffness degradation method to predict in-ply damage initiation and evolution of composite laminates.
The progressive damage model was implemented in commercial finite element software #ABAQUS by a #USDFLD #subroutine.
The capability of the proposed model was validated by predicting four different samples:
1- Open-hole compression specimen test,
2- Simple plate tension test [+-45],
3- Open-hole tension specimen test with [+-30]2s layup and
4- Open hole tensile specimen test with [+-35/0/90]s layup.
learn more https://en.banumusagr.com/shop/3d-hashin-failure-criteria-usdfld-subroutine-for-abaqus/
"Simulating Van der Waals interaction using Abaqus"
Van der Waals interactions occur between molecules due to temporary shifts in electron density, causing them to attract each other. This phenomenon can be crucial when the length scale of a structure is in the nano to micro meter range.
In the animation below, the Van der Waals interaction was implemented based on the Coarse-Grained Contact Model (CGCM) proposed by Sauer and Li in 2007. The CGCM assumes that the influential distance of the Van der Waals interaction is significantly smaller than the surface curvature, making it possible to derive the surface-to-surface potential from the Lennard-Jones potential (intermolecular potential). The model is valid as long as the surface curvature is more than 10 times larger than the influential distance, which applies to most finite element analysis (FEA) applications.
The CGCM was implemented with the UINTER (User Interaction) subroutine in Abaqus and validated with an analytical solution by Johnson-Kendall-Roberts (JKR). The force-displacement curve from the spherical indentation was predicted using the JKR model and compared with the Abaqus 2D axisymmetric model. The results show good agreement.
#Abaqus #SIMULIA #VanderWaals #MEMS #NEMS #Subroutine #FEA #FiniteElement #Simulation
References
[1] Gaffari R, Dong TX, Sauer RA, 2018, A new shell formulation for graphene structures based on existing ab-initio data, International Journal of Solids and Structures 135, 37-60.
[2] Sauer RA, Li S, 2007, An atomic interaction-based continuum model for adhesive contact mechanics, Finite Elements in Analysis and Design 43, 384-396.
[3] Sauer RA, Wriggers P, 2009, Formulation and analysis of a three-dimensional finite element implementation for adhesive contact at the nanoscale, Computer Methods in Applied Mechanics and Engineering 198, 3871-3883.
Van der Waals interactions occur between molecules due to temporary shifts in electron density, causing them to attract each other. This phenomenon can be crucial when the length scale of a structure is in the nano to micro meter range.
In the animation below, the Van der Waals interaction was implemented based on the Coarse-Grained Contact Model (CGCM) proposed by Sauer and Li in 2007. The CGCM assumes that the influential distance of the Van der Waals interaction is significantly smaller than the surface curvature, making it possible to derive the surface-to-surface potential from the Lennard-Jones potential (intermolecular potential). The model is valid as long as the surface curvature is more than 10 times larger than the influential distance, which applies to most finite element analysis (FEA) applications.
The CGCM was implemented with the UINTER (User Interaction) subroutine in Abaqus and validated with an analytical solution by Johnson-Kendall-Roberts (JKR). The force-displacement curve from the spherical indentation was predicted using the JKR model and compared with the Abaqus 2D axisymmetric model. The results show good agreement.
#Abaqus #SIMULIA #VanderWaals #MEMS #NEMS #Subroutine #FEA #FiniteElement #Simulation
References
[1] Gaffari R, Dong TX, Sauer RA, 2018, A new shell formulation for graphene structures based on existing ab-initio data, International Journal of Solids and Structures 135, 37-60.
[2] Sauer RA, Li S, 2007, An atomic interaction-based continuum model for adhesive contact mechanics, Finite Elements in Analysis and Design 43, 384-396.
[3] Sauer RA, Wriggers P, 2009, Formulation and analysis of a three-dimensional finite element implementation for adhesive contact at the nanoscale, Computer Methods in Applied Mechanics and Engineering 198, 3871-3883.
یکی از اشتباهات رایجی که در سابروتین نویسی انجام میشه، وقتی پیش میاد که قراره یه سری دیتا از یک فایل *.txt یا *.csv خونده بشه.
اکثرا این کار رو در خود سابروتین مثلا USDFLD یا UMAT انجام میدن و این باعث میشه در هر گام یا increment این داده ها در سابروتین خونده بشن که وحشتناک سرعت محاسبات رو کم میکنه. همچنین حجم بسیاری زیادی از ram و کش cpu رو میگیره.
برای حل این مشکل کافیه از سابروتین uexternaldb استفاده بشه. یه سابروتین خیلی ساده که برای همین کار درنظر گرفته شده. امتحان کنید تفاوت رو متوجه میشید!
برای رفع اشکالات سابروتین نویسی در اباکوس تماس بگیرید.
#abaqus #subroutine #uexternaldb
اکثرا این کار رو در خود سابروتین مثلا USDFLD یا UMAT انجام میدن و این باعث میشه در هر گام یا increment این داده ها در سابروتین خونده بشن که وحشتناک سرعت محاسبات رو کم میکنه. همچنین حجم بسیاری زیادی از ram و کش cpu رو میگیره.
برای حل این مشکل کافیه از سابروتین uexternaldb استفاده بشه. یه سابروتین خیلی ساده که برای همین کار درنظر گرفته شده. امتحان کنید تفاوت رو متوجه میشید!
برای رفع اشکالات سابروتین نویسی در اباکوس تماس بگیرید.
#abaqus #subroutine #uexternaldb