scholarly journals Experimental Verification of the Elastic Response in a Numeric Model of a Composite Propeller Blade with Bend Twist Deformation

Polymers ◽  
2021 ◽  
Vol 13 (21) ◽  
pp. 3766
Author(s):  
Sondre Østli Rokvam ◽  
Nils Petter Vedvik ◽  
Lukas Mark ◽  
Eivind Rømcke ◽  
Jon Schawlann Ølnes ◽  
...  
Keyword(s):  
Finite Element ◽  
Twist Angle ◽  
Point Load ◽  
Image Correlation ◽  
Elastic Response ◽  
Propeller Blade ◽  
Element Analysis ◽  
Numeric Model ◽  
Load Variable ◽  
Adaptive Composite

Adaptive composite propeller blades showing bend twist behaviour have received increasing interest from hydrodynamic and structural engineers. When exposed to periodic loading conditions, such propellers can be designed to have higher energy efficiency and emit less noise and vibration than conventional propellers. This work describes a method to produce an adaptive composite propeller blade and how a point load experiment can verify the predicted elastic response in the blade. A 600 mm-long hollow full-size blade was built and statically tested in the laboratory. Finite element modelling predicted a pitch angle change under operational load variable loads of 0.55°, a geometric change that notably compensates for the load cases. In the laboratory experiment, the blade was loaded at two points with increasing magnitude. The elastic response was measured with digital image correlation and strain gauges. Model predictions and experimental measurements showed the same deformation patterns, and the twist angle agreed within 0.01 degrees, demonstrating that such propellers can be successfully built and modelled by finite element analysis.

Development of Stress Intensification Factors for Collared Type Piping Joints

2020 ◽  
Author(s):  
Cameron Ewing
Keyword(s):  
Finite Element ◽  
Carbon Steel ◽  
Electrode Materials ◽  
Real Life ◽  
Strain Curve ◽  
Bending Moment ◽  
Peak Stress ◽  
Point Load ◽  
Element Analysis ◽  
Transfer Lines

Abstract Stress Intensification Factors or SIFs allow piping to be analyzed using beam theory, with a SIF representing local effects of specific piping geometry. However, the current piping codes do not explicitly provide SIFs for collared type piping joints for use in pipe stress calculations. The objective of this paper is to describe the methodology on how a finite element analysis (FEA) was to model the behavior of collared joints, and to ultimately develop appropriate SIFs that can be used in pipe stress analyses. This paper describes a real-life analysis example on collared joints installed on a set of existing fuel transfer lines. The lines, which ranged in size from DN200 to DN350, were concrete lined carbon steel with the collars fillet welded to the carbon steel section of the piping. Test coupons cut from existing pipe-collar sections were tested in a laboratory to determine the forces required to break the collar welds. Using FEA, the same test coupons were modelled to replicate the failure tests. Multiple iterations were undertaken to determine an appropriate bi-linear stress-strain curve fit for the weld material. The curves of different weld electrode materials were considered. The curve which lead to results similar to those observed in physical testing was selected. From this, a failure stress across the weld could be determined. This stress, 435MPa was then used in subsequent models to determine the point at which the weld fails under bending loads. Multiple tests were analyzed to allow for possible effects of inclusions and voids. Finite element models of the collar geometries were constructed and non-linear analyses were undertaken using the weld strengths determined from the coupon testing data. A simple cantilever type arrangement with a point load at one end was analyzed, inducing a bending moment across the collar. The peak stress resulting from the bending moment across the collar weld at the center of the cantilevered pipe arrangement, was investigated across various pipe diameters, wall thicknesses, weld sizes and collar geometries. Based on the results, a relationship between the pipe geometry and SIF was developed. Hence a pipe stress model of the transfer lines could ultimately be developed using these SIFs to predict the behavior of the piping.

Evaluation of Transverse Shear Moduli of Composite Sandwich Beams Through Three-Point Bending Tests

2018 ◽  
Author(s):  
Özgün Şener ◽  
Oğuzhan Dede ◽  
Oğuz Atalay ◽  
Mert Atasoy ◽  
Altan Kayran
Keyword(s):  
Finite Element ◽  
Transverse Shear ◽  
Sandwich Beam ◽  
Image Correlation ◽  
Core Material ◽  
Flexural Stiffness ◽  
Element Analysis ◽  
Bending Tests ◽  
Shear Moduli ◽  
Composite Sandwich

Transverse shear moduli of the sandwich core and flexural stiffness of all-composite sandwich constructions are determined with three-point beam bending tests, and compared with the analytical and finite element analysis solutions. Additionally, Digital Image Correlation (DIC) system is employed to validate the experimental results by monitoring the displacements. The effect of orientation of the composite core material with respect to the beam axis on the shear modulus of the core material itself, flexural stiffness of the sandwich beam, maximum loading, and the maximum stresses on the sandwich panel are also examined. Comparable results are achieved through experiments, finite element and analytical analyses.

Shear Test on CFRP Full-Field Measurement and Finite Element Analysis

2010 ◽  
Vol 112 ◽  
pp. 49-62 ◽  
Author(s):  
Sébastien Mistou ◽  
Marina Fazzini ◽  
Moussa Karama
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Shear Modulus ◽  
Shear Test ◽  
Image Correlation ◽  
Optical Methods ◽  
Strain Gauges ◽  
Element Analysis ◽  
Full Field ◽  
Full Field Measurement

The purpose of this work is to study the Iosipescu shear test and more precisely its ability to characterize the shear modulus of a carbone/epoxy composite material. The parameters influencing this identification are the fibre orientation, the geometry of the notch and the boundary conditions. Initially these parameters were studied through the finite element analysis of the shear test. Then, the measurement of the shear strains was carried out by traditional methods of measurement (strain gauges) but also by optical methods. These optical methods: the digital image correlation and the electronic speckle pattern interferometry (ESPI); allow for various levels of loading, to reach a full-field measurement of the shear strain. This enabled us to study the strain distribution on the section between the two notches. The finite element model enabled us to study the parameters influencing the calculation of the shear modulus in comparison with strain gauges, image correlation and ESPI. This work makes it possible to conclude on optimal parameters for the Iosipescu test.

scholarly journals Extracting elastic constitutive parameters using the VFM within peridynamics

2019 ◽  
Author(s):  
Rolland Delorme ◽  
Patrick Diehl ◽  
Ilyass Tabiai ◽  
Louis Laberge Lebel ◽  
Martin Levesque
Keyword(s):  
Finite Element ◽  
Displacement Field ◽  
Material Properties ◽  
Noise Analysis ◽  
Image Correlation ◽  
Bending Test ◽  
Virtual Fields Method ◽  
Element Analysis ◽  
Constitutive Parameters

This paper implements the Virtual Fields Method within the ordinary state based peridynamic framework to identify material properties. The key equations derived in this approach are based on the principle of virtual works written under the ordinary state based peridynamic formalism for two-dimensional isotropic linear elasticity. In-house codes including a minimization process have also been developed to implement the method. A three-point bending test and two independent virtual fields arbitrarily chosen are used as a case study throughout the paper. The numerical validation of the virtual fields method has been performed on the case study by simulating the displacement field by finite element analysis. This field has been used to extract the elastic material properties and compared them to those used as input in the finite element model, showing the robustness of the approach. Noise analysis and the effect of the missing displacement fields on the specimen’s edges to simulate digital image correlation limitations have also been studied in the numerical part. This work focuses on pre-damage properties to demonstrate the feasibility of the method and provides a new tool for using full-field measurements within peridynamics with a reduced calculation time as there is no need to compute the displacement field. Future works will deal with damage properties which is the main strength of peridynamics.

Vibration of cold-formed steel floors with a steel form deck and gypsum-based self-leveling underlayment

2019 ◽  
Vol 22 (13) ◽  
pp. 2741-2754
Author(s):  
Yu Guan ◽  
Xuhong Zhou ◽  
Xinmei Yao ◽  
Yu Shi
Keyword(s):  
Finite Element ◽  
Fundamental Frequency ◽  
Damping Ratio ◽  
Point Load ◽  
Element Analysis ◽  
Static Tests ◽  
Floor Systems ◽  
Cold Formed Steel ◽  
Center Deflection ◽  
Deflection Limit

The vibration response and static deflection of cold-formed steel floor systems with a form deck and gypsum-based self-leveling underlayment were investigated through an experimental study and a finite element analysis. The floor system was constructed with cold-formed steel joists as supports and a cold-formed steel form deck subfloor with gypsum-based self-leveling underlayment on the surface. Dynamic tests and 1 kN static tests were carried out on three specimens, and design specifications including shear resistance construction and floor width were varied to explore their effects on the fundamental frequency, damping ratio, and center deflection of floors. Then, finite element models were developed and verified with the experimental test results, and parametric studies were conducted to consider the effect of boundary conditions on the vibration performance of the same floor systems. Based on the result, a minimum limit of fundamental frequency of 10 Hz and a maximum center deflection limit under a 1 kN point load of 1 mm were recommended for cold-formed steel floor systems with a form deck and gypsum-based self-leveling underlayment. Finally, methods to calculate the fundamental frequency and center deflection of this floor systems were proposed.

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