On Modeling and Assessment of Bulk Liquid Storage Tanks With Foundation Settlements

Author(s):  
Mingxin Zhao

Abstract A comprehensive study is conducted on finite element modeling and stress analysis techniques of above ground atmospheric bulk liquid storage tanks with foundation settlements. Both 2-D and 3-D modeling are examined for their applicability and limitations. Simple elastic analysis and 3-step method using a hybrid elastic-plastic procedure are explored and compared. In addition, data processing techniques are proposed to extract effective settlements from tank inspection measurements, which could be used for proper reconstruction of a settled foundation in finite element model. Procedures and practices are proposed and demonstrated to improve the finite element modeling and analysis of storage tanks.

Author(s):  
Anagha G. Jog ◽  
Ian R. Grosse ◽  
Daniel D. Corkill

Abstract Currently, the pre-processing stage of finite element analysis is a major stumbling block towards automation of the entire finite element modeling and analysis (FEMA) process. The lack of complete automation of FEMA greatly limits its impact as a design tool. This paper presents a blackboard-based, object-oriented modeling system for intelligent a-priori automatic three dimensional mesh generation. The modeling system enables the user to define the physical system at a natural domain-specific high level of abstraction and automatically derives lower-level finite element model representations. Knowledge sources interact with the blackboard to make modeling idealizations and select optimal meshing strategies. An example application in the domain of finite element modeling of multi-chip module microelectronic devices is presented.


2021 ◽  
pp. 107754632110267
Author(s):  
Jiandong Huang ◽  
Xin Li ◽  
Jia Zhang ◽  
Yuantian Sun ◽  
Jiaolong Ren

The dynamic analysis has been successfully used to predict the pavement response based on the finite element modeling, during which the stiffness and mass matrices have been established well, whereas the method to determine the damping matrix based on Rayleigh damping is still under development. This article presents a novel method to determine the two parameters of the Rayleigh damping for dynamic modeling in pavement engineering. Based on the idealized shear beam model, a more reasonable method to calculate natural frequencies of different layers is proposed, by which the global damping matrix of the road pavement can be assembled. The least squares method is simplified and used to calculate the frequency-independent damping. The best-fit Rayleigh damping is obtained by only determining the natural frequencies of the two modal. Finite element model and in-situ field test subjected by the same falling weight deflectometer pulse loads are performed to validate the accuracy of this method. Good agreements are noted between simulation and field in-situ results demonstrating that this method can provide a more accurate approach for future finite element modeling and back-calculation.


2018 ◽  
Vol 9 (4) ◽  
pp. 504-524 ◽  
Author(s):  
Gaurav Nilakantan

This work presents the first fully validated and predictive finite element modeling framework to generate the probabilistic penetration response of an aramid woven fabric subjected to ballistic impact. This response is defined by a V0-V100 curve that describes the probability of complete fabric penetration as a function of projectile impact velocity. The exemplar case considered in this article comprises a single-layer, fully clamped, plain-weave Kevlar fabric impacted at the center by a 0.22 cal spherical steel projectile. The fabric finite element model comprises individually modeled three-dimensional warp and fill yarns and is validated against the experimental material microstructure. Sources of statistical variability including yarn strength and modulus, inter-yarn friction, and precise projectile impact location are mapped into the finite element model. A series of impact simulations at varying projectile impact velocities is executed using LS-DYNA on the fabric models, each comprising unique mappings. The impact velocities and outcomes (penetration, non-penetration) are used to generate the numerical V0-V100 curve which is then validated against the experimental V0-V100 curve obtained from ballistic impact testing and shown to be in excellent agreement. The experimental data and its statistical analysis used for model input and validation, namely, the Kevlar yarn tensile strengths and moduli, inter-yarn friction, and fabric ballistic impact testing, are also reported.


Author(s):  
Santosh Shanbhag ◽  
Ian R. Grosse ◽  
Jack C. Wileden ◽  
Alan Kaplan

Abstract With the integration of CAD and FEA software packages, design engineers who are not skilled in finite element analysis are performing finite element modeling and analysis. Furthermore, in the analysis of a system, engineers often make numerous modeling simplifications and analysis assumptions depending on the trade-off between cost, accuracy, precision or other engineering analysis objectives. Thus, reusability or interoperability of engineering analysis models is difficult and often impractical due to the wealth of knowledge involved in the creation of such models and the lack of formal methods to codify and explicitly represent this critical modeling knowledge. Most institutions and organizations have started documenting these simplifications and assumptions, making them understandable for the other engineers within the organization. However, this does not allow a seamless exchange of data or interoperability with other analysis models of similar or dissimilar nature. This plays a very important role in today’s market, which is moving away from the traditional make-to-stock production model to a build-to-demand model. We address these issues in this paper by adopting and extending the computer science concept of meta-object, and applying it in novel ways to the domain of FEA and the representation of finite element modeling knowledge. We present a taxonomy for engineering models that aids in the definition of the various object analysis classes. A simple beam analysis example, followed by a more realistic injection-molded part example. The latter example involves injection-mold filling simulation, thermal cooling, and part ejection analyses which are subclasses for a generic manufacturing analysis meta-object class. Prototype implementations of automated support for this meta-object approach to finite element modeling is in progress.


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