Nonlinear Membrane Direct and Inverse FEM Analysis

2014 ◽  
Author(s):  
Mattia Alioli ◽  
Pierangelo Masarati ◽  
Marco Morandini ◽  
Trenton Carpenter ◽  
Roberto Albertani
Keyword(s):  
Three Dimensional ◽  
Fem Analysis ◽  
Solution Procedure ◽  
General Purpose ◽  
Inverse Solution ◽  
Surface Strain ◽  
Image Correlation ◽  
Direct Solution ◽  
Strain Measurements ◽  
Solution Approach

The analysis of thin structural components integrated within a general-purpose multibody system dynamics formulation is presented. An original inverse finite element solution procedure is developed to reconstruct the deformed shape of a membrane from in-plane membrane strain measurements, and eventually indirectly estimate the distributed loads. A direct solution approach is used in co-simulation with fluid-dynamics solvers to predict the configuration of the system under static and unsteady loads. Numerical validation of the inverse solution is performed considering the results of direct solution analysis. The direct and inverse solutions are validated considering experimental displacement and strain measurements obtained using digital image correlation. Moving Least Squares are used to smooth and remap measurements as needed by the inverse solution meshing. Utilizing surface strain measurements from strain sensors, the methodology enables the accurate computation of the three-dimensional displacement field.

Membrane Shape and Transverse Load Reconstruction Using Inverse FEM

2015 ◽  
Author(s):  
Mattia Alioli ◽  
Pierangelo Masarati ◽  
Marco Morandini ◽  
Trenton Carpenter ◽  
N. Brent Osterberg ◽  
...  
Keyword(s):  
Broad Class ◽  
Direct Analysis ◽  
General Purpose ◽  
Surface Strain ◽  
Image Correlation ◽  
Transverse Load ◽  
Full Field ◽  
Strain Measurements ◽  
Load Distributions ◽  
Tightly Coupled

Thin structural components characterize a broad class of Micro-Aerial Vehicles (MAV). This work presents an original approach for the determination of transverse load distribution based on distributed strain measurements. A variational formulation is developed for the inverse problem of the reconstruction of full-field structural displacement of membrane wings subjected to static and unsteady loads. Surface strain measurements are estimated from Digital Image Correlation (DIC). Moving Least Squares are used to smooth and remap measurements as needed by the inverse solution meshing, and to map the structural and fluid interface kinematics and loads during the fluid-structure co-simulation. The inverse analysis is verified by reconstructing the deformed solution obtained with an analogous direct formulation, based on nonlinear membrane structural analysis implemented in a general-purpose multibody solver and tightly coupled in co-simulation with a CFD solver. The direct analysis is performed on a different mesh and subsequently re-sampled. Both the direct and the inverse analyses are validated by comparing the direct predictions and the reconstructed deformations with experimental data for prestressed rectangular membranes subjected to static and unsteady loads. The reconstructed load distributions are compared with the corresponding ones obtained using the direct analysis.

Flexural Behavior of a Layer-to-Layer Orthogonal Interlocked Three-Dimensional Textile Composite

2012 ◽  
Vol 134 (3) ◽  
Author(s):  
D. Zhang ◽  
A. M. Waas ◽  
M. Pankow ◽  
C. F. Yen ◽  
S. Ghiorse
Keyword(s):  
Mechanical Response ◽  
Peak Load ◽  
Three Dimensional ◽  
Peak Stress ◽  
Surface Strain ◽  
Image Correlation ◽  
Flexural Behavior ◽  
Fe Model ◽  
Textile Composite ◽  
The Matrix

The flexural response of a three-dimensional (3D) layer-to-layer orthogonal interlocked textile composite has been investigated under quasi-static three-point bending. Fiber tow kinking on the compressive side of the flexed specimens has been found to be a strength limiting mechanism for both warp and weft panels. The digital image correlation (DIC) technique has been utilized to map the deformation and identify the matrix microcracking on the tensile side prior to the peak load in the warp direction loaded panels. It has been shown that the geometrical characteristics of textile reinforcement play a key role in the mechanical response of this class of material. A 3D local–global finite element (FE) model that reflects the textile architectures has been proposed to successfully capture the surface strain localizations in the predamage region. To analyze the kink banding event, the fiber tow is modeled as an inelastic degrading homogenized orthotropic solid in a state of plane stress based on Schapery Theory (ST). The predicted peak stress is in agreement with the tow kinking stress obtained from the 3D FE model.

scholarly journals Bio-Inspired 3D Infill Patterns for Additive Manufacturing and Structural Applications

Materials ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 499 ◽  
Author(s):  
Jan Podroužek ◽  
Marco Marcon ◽  
Krešimir Ninčević ◽  
Roman Wan-Wendner
Keyword(s):  
Additive Manufacturing ◽  
Mechanical Performance ◽  
Peak Load ◽  
Fem Analysis ◽  
Material Model ◽  
Surface Strain ◽  
Image Correlation ◽  
Nonlinear Material ◽  
Full Field ◽  
Structural Applications

The aim of this paper is to introduce and characterize, both experimentally and numerically, three classes of non-traditional 3D infill patterns at three scales as an alternative to classical 2D infill patterns in the context of additive manufacturing and structural applications. The investigated 3D infill patterns are biologically inspired and include Gyroid, Schwarz D and Schwarz P. Their selection was based on their beneficial mechanical properties, such as double curvature. They are not only known from nature but also emerge from numerical topology optimization. A classical 2D hexagonal pattern has been used as a reference. The mechanical performance of 14 cylindrical specimens in compression is quantitatively related to stiffness, peak load and weight. Digital image correlation provides accurate full-field deformation measurements and insights into periodic features of the surface strain field. The associated variability, which is inherent to the production and testing process, has been evaluated for 3 identical Gyroid specimens. The nonlinear material model for the preliminary FEM analysis is based on tensile test specimens with 3 different slicing strategies. The 3D infill patterns are generally useful when the extrusion orientation cannot be aligned with the build orientation and the principal stress field, i.e., in case of generative design, such as the presented branching structure, or any complex shape and boundary condition.

Bearing Capacity of Suction Caisson Foundations Using FEM Analysis

2011 ◽  
Vol 243-249 ◽  
pp. 2112-2115
Author(s):  
Zhi Yun Wang ◽  
Mao Tian Luan ◽  
Lu Shen
Keyword(s):  
Bearing Capacity ◽  
Three Dimensional ◽  
Numerical Procedure ◽  
Fem Analysis ◽  
General Purpose ◽  
Combine Loading ◽  
Element Analysis ◽  
Suction Caisson ◽  
Caisson Foundations ◽  
Suction Caisson Foundation

To understand features of bearing capacity of suction caisson foundation is one of the key issues in design and construction of deep-water marine structures. In this paper, the general-purpose finite element analysis package ABAQUS is employed to conduct three-dimensional numerical analyses on load-carrying features of suction caisson foundation under vertically uplift load, horizontal load and moment. Then the ultimate bearing capacity of suction caisson foundation for undrained condition of the soil is evaluated by displacing-controlling procedure. Moreover, three-dimensional failure envelope of suction caisson foundation under combine loading condition are established by the proposed numerical procedure.

scholarly journals A method for predicting the blasting pressure of balloons using the surface strain in low pressure

2019 ◽  
Vol 11 (10) ◽  
pp. 168781401988155
Author(s):  
Yong-Zheng Shen ◽  
Guo-Chang Lin ◽  
Hui-Feng Tan
Keyword(s):  
Internal Pressure ◽  
Correction Factor ◽  
Three Dimensional ◽  
Reference Value ◽  
Surface Strain ◽  
Test Strain ◽  
Image Correlation ◽  
Correlation Technique ◽  
Maximum Test ◽  
Novel Method

Balloons made by cut fabric pieces are widely used in space research. To predict the blasting pressure of a balloon, we propose a novel method based on the non-contact test strain at a low internal pressure. The three-dimensional digital image correlation technique is introduced to measure the surface strain of the balloon. Representative regions of the balloon are selected as the test regions. A correction factor is proposed that accounts for the relationship between the internal pressure and the surface strain for the actual and the ideal balloon. By combining the maximum surface strain at a given internal pressure and the correction factor, we can predict the blasting pressure of the balloon. A blasting test is carried out to verify the feasibility of the predictive method. When the value of the ratio of the maximum test strain to the limiting strain reaches about a reference value, the absolute value of the deviation percentage between the predicted blasting pressure and the actual blasting pressure is less than 10%. The blasting pressure for balloon can be predicted accurately. This method does not require the balloon to be inflated to a high internal pressure, which improves the practicality of the prediction.

scholarly journals Biomechanical Comparison of a Notched Head Locking T-Plate and a Straight Locking Compression Plate in a Juxta-Articular Fracture Model

2020 ◽  
Author(s):  
Guy Bird ◽  
Mark Glyde ◽  
Giselle Hosgood ◽  
Alex Hayes ◽  
Robert Day
Keyword(s):  
Three Dimensional ◽  
Locking Compression Plate ◽  
Surface Strain ◽  
Image Correlation ◽  
Fracture Model ◽  
Articular Fracture ◽  
Short Fragment ◽  
Working Length ◽  
Compression Plate ◽  
Short Working

Abstract Objective This investigation compared the biomechanical properties of a 2.0 mm locking compression notched head T-plate (NHTP) and 2.0 mm straight locking compression plate (LCP), in a simple transverse juxta-articular fracture model. Study Design Two different screw configurations were compared for the NHTP and LCP, modelling short (configuration 1) and long working length (configuration 2). Constructs were tested in compression, perpendicular and tension non-destructive four point bending and torsion. Plate surface strain was measured at 12 regions of interest (ROI) using three-dimensional digital image correlation. Stiffness and strain were compared between screw configurations within and between each plate. Results The LCP was stiffer than the NHTP in all three planes of bending and torsion (p < 0.05). The NHTP had greater strain than the LCP during compression bending and torsion at all ROI (p < 0.0005). The short working length was stiffer in all three planes of bending and in torsion (p < 0.05) than the longer working length for both plates. The long working length showed greater strain than the short working length at most ROI. Conclusion In this experimental model, a 2.0 mm LCP with two screws in the short fragment was significantly stiffer and had lower plate strain than a 2.0 mm NHTP with three screws in the short fragment. Extending the working length significantly reduced construct stiffness and increased plate strain. These findings may guide construct selection.

Development of a Residual Stress Evaluation Technique by the Combined Use of Surface Strain Measurements Under the Spherical Indentation Method

2013 ◽  
Author(s):  
Norihiko Ozawa ◽  
Tomoaki Yoshizawa ◽  
Yutaka Watanabe ◽  
Tetsuo Shoji
Keyword(s):  
Residual Stresses ◽  
Elastic Strain ◽  
Fem Analysis ◽  
Indentation Load ◽  
Surface Strain ◽  
Spherical Indentation ◽  
Maximum Pressure ◽  
Strain Measurements ◽  
Combined Use ◽  
Compressive Residual Stresses

In this research, a technique was developed for quantitatively evaluating the amount and distribution of tensile and compressive residual stresses by the combined use of strain measurements under the spherical indentation loading together with the finite element method (FEM). When the spherical indentation is applied to the top surface of a welded plate, the elastic strain at an optimized position near the indentation is measured by strain gauges, where the residual and applied indentation stresses are largely superposed. In order to analyze the residual stresses, FEM analysis was conducted to establish the relationship between the elastic strain adjacent to the indentation and the indentation pressure for plates subjected to various uniform tensile and compressive stresses. The critical indentation load was identified, which maximizes the difference between the tensile and compressive residual stresses. A strain energy term (U*) is newly introduced by integrating along the trajectory between the indentation pressure and the elastic strain in a range from 0 to maximum pressure. The application of this technique could contribute to improved reliability in welded parts.

scholarly journals Effect of Plate Type and Working Length on a Synthetic Compressed Juxta-Articular Fracture Model

VCOT Open ◽  
2020 ◽  
Vol 03 (02) ◽  
pp. e119-e128
Author(s):  
Guy Bird ◽  
Mark Glyde ◽  
Giselle Hosgood ◽  
Alex Hayes ◽  
Rob Day
Keyword(s):  
Three Dimensional ◽  
Biomechanical Properties ◽  
Regions Of Interest ◽  
Surface Strain ◽  
Image Correlation ◽  
Fracture Model ◽  
Short Fragment ◽  
Working Length ◽  
Multiple Regions ◽  
Short Working

Abstract Objective This investigation compared the biomechanical properties of a 2.0 mm locking compression notched head T-plate (NHTP) and 2.0 mm straight locking compression plate (LCP), in a compressed, short, juxta-articular fragment fracture model. Methods Two different screw configurations were compared for the NHTP and LCP, modelling short (configuration 1) and long working length (configuration 2). Constructs were tested in compression, perpendicular and tension four-point bending and torsion. Plate surface strain was measured at 12 regions of interest using three-dimensional digital image correlation. Stiffness and strain were compared. Results The LCP was stiffer than the NHTP in all three planes of bending (p < 0.05). The NHTP was stiffer than the LCP in torsion (p < 0.05). The NHTP had greater strain than the LCP during compression bending and torsion (p < 0.0005). The short working length NHTP was stiffer in all three planes of bending and in torsion (p < 0.05) than the longer working length. The short working length LCP was stiffer in compression bending and in torsion (p < 0.05) than the longer working length. The long working length showed greater strain than the short working length at multiple regions of interest. Conclusion In this experimental model of a compressed transverse fracture with a juxta-articular 9 mm fragment, a 2.0 mm LCP with two hybrid screws in the short fragment was stiffer than a 2.0 mm NHTP with three locking screws in the short fragment in three planes of bending but not torsion. Extending the working length of each construct reduced construct stiffness and increased plate strain.

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