Featured Structural Consulting Services Success Case Studies
Investigation of retrieving In-plane Stress and Deformations or Strain and Displacement
1. FEA Simulation objective:
The simulation objective was investigating the retrieve In-plane Stress and Deformations or Strain and Displacement inflicting various loads to this model
2. FEA Simulation Methodology and Approach:
Multiple Methodology methods were used beginning with basic plane stress elements and plane strain elements followed by shell elements, beam elements, and 3-D solid elements, the 3D element method was then compared with stress and strain element, shell elements for further verifications.
3. Outcome & Conclusion
The analysts of each type of elements we generated give various results, to compare them with relativity and accuracy we pair them with the same force location setup, and The data generated for the 4 part question has 405 nodes while Beam has 8 node s , all of the data can’t be presented nor analyzed as the data size is large, However, we can analyze with the Maximum and minimum data generated by abaqus which are in average form.
The Plane Stress and Plane strain analyst’s projects only its main characteristics of Stress and strain which will not be appropriate to compare both together however both will be compared with Shell element characteristics as Plane stress and strain are part of the shell components and so will shell, beam and solid 3D
The data figures indicate that all three Elements possesses relatively the same figures but for Plane strain E11 figure is slightly off as plane strain mainly concentrates on Strain characteristics, the best option is to use shell element to analyze the Plane Stress and Strain because it’s more accurate and enables to generate plane stress/strain in one analyst.
While comparing Beam element and 3D elements while the rest of the elements indicates strongly that Beam possesses high Ridged characteristics then rest or the elements as the beam is constructed to handle heavier loads, while the 3D solid element is capable of producing all the 4 characteristics of plane stress/strain and shell although it’s convenient and also expensive to use as 3D analysts cost more to generate
Design of a novel specimen geometry to facilitate multi-axial loading of crushable foams
1. FEA Simulation objective::
Owing to the complex porous nature of metal foams, customized experimental investigations are necessary for studying the multiaxial loading response of closed-cell aluminum foams. The objective of this project is to develop a customized specimen geometry using the FEA approach that facilitates the effective transfer of desired stress states under biaxial compression, biaxial tension, and shear loading conditions.
2. FEA Simulation Methodology and Approach:
A modified Maltese cross specimen, a simplified form of a Maltese cross is considered as an ideal alternative.
The effectiveness of the proposed specimens is preliminarily investigated numerically using commercial finite element analysis software – ABAQUS. The crushable foam model is adopted for closed-cell aluminum foams of a relative density of 16%. The crushable foam parameters are adopted based on the experimental values reported in previous studies: density = 432 kg/m3,
Young’s Modulus = 1.1 GPa, plastic Poisson’s ratio = 0.22, uniaxial yield strength = 2.0 MPa and compression yield stress ratio (ratio of deviatoric to hydrostatic compressive strength) = 1.25. The crushable foam hardening values are extracted based on the stress-strain response of foams under uniaxial compression reported therewith. The profiles of effective plastic strain (PEEQ in ABAQUS) distribution of the MMC specimens under biaxial tension, biaxial compression, and tension-compression loading conditions are found to be ideal, without any shearing of the ear region. It can be seen that under biaxial tension, when tensile strains are applied along with directions 1 and 2, the effective plastic strain is uniformly distributed in the core region of the MMC specimen, indicating the effect of the desired stress state. Consistently, under biaxial compression,
the effective plastic strain distribution is almost uniformly distributed in the core region of the MMC specimen. Under tension-compression loading conditions, when the combination of compressive strain along direction 1 and tensile strain along direction 2 is applied at equal strain rates, the effective plastic strain is highly concentrated along the diagonals of the sample, indicating the effect of shear. This preliminary study thus highlights the potential effectiveness of the proposed MMC geometry to adequately represent the desired stress states.
A similar analysis was carried out to design machine fixtures, which will be attached to the MTS Biaxial 100kN loading machine, that facilitate the above-mentioned loading conditions.
3. Project Conclusion & Outcomes:
The Modified Maltese cross specimen geometry that was developed in this project consists of a much simpler geometry.
The geometry consists of waisted specimens, with waist lengths are 55mm, sufficiently long enough to avoid shearing away of the ear region, when the specimens are subjected to biaxial tension. The dimensions of the core being approximately 40x40x60 mm. Since the average pore size of many
commercially available metal foams ranges between 3 mm to 5 mm, the dimension of the proposed core encompasses more than 7 cells in all the principal directions, hence enabling the extraction of representative material behavior.
This simpler geometry also assists towards the easier fabrication of the samples, thus proving to be an economical alternative to Maltese Cross Specimens in case of biaxial loading experiments, without significant delay due to the use of epoxy adhesives.
The experimental investigations carried out from the proposed specimen geometry from the FEA analyses lead to the development of a new yield criterion for metal foams, ideally applicable for efficient engineering designs.
Distributed memory parallel processing
Simcenter Femap NX Nastran Dynamically distributed memory parallel processing (DMP) solutions can be Solved on a single CPU node or in Parallel across Several Computing nodes.
When Solving the FEM Simulation
in DMP mode, Simcenter Femap Nastran spins off multiple Computational processes that Closely communicate via the CPU Message Passing Interface (MPI) within or across nodes.
Simcenter Femap NX Nastran Provides the following methods for Highly distributed CPU processing:
Geometric domain partitioning
Geometric domain partitioning is Accessible for Both static and dynamic FEM Modeling Software
The system-level Matrix is automatically partitioned and Dynamically Allocated to different MPI Workflow processes.
Frequency domain partitioning
Frequency domain partitioning is Also Accessible for dynamic FEM Simulation Software
Simulation solutions. The frequency range of interest for eigenvalue Numerical computation as well as frequency response is Intelligently partitioned into Corresponding segments that are Allocated to Various MPI processes.
Hierarchic domain partitioning
Hierarchic domain partitioning is a combination of geometric and frequency domain Approaches.
This Methodology is used for modal FEM Analysis Software
Simulation solutions and Enables Full scalability to higher levels than could be achieved with either Analysis method individually.
Load domain partitioning
Load domain partitioning is Highly useful when there is a large/Huge Quantity of Loading Scenarios in a linear static FEA Software
Instead of Only partitioning the finite element model (FEM), the Force Loading matrix is Automatically partitioned among MPI load domain partitioning, which does not need Back and Forth communication between CPU processors, and is nearly linearly scalable.