Prediction of Wrinkling Initiation and Growth in Aluminum 5456-H116, Alloy Sheets by Finite Element Analysis of Yoshida Test

2012 ◽  
Vol 197 ◽  
pp. 686-690
Author(s):  
Amer Sattar ◽  
Irfan Anjum Manarvi ◽  
Manzar Masud
Keyword(s):  
Finite Element ◽  
Yield Strength ◽  
Thin Sheet ◽  
Aviation Industry ◽  
Good Tool ◽  
Element Analysis ◽  
Metal Plates ◽  
Initiation And Propagation ◽  
Metal Sheets ◽  
Thin Sheet Metal

Wrinkling is one of the most undesirable effects during forming of thin sheet metal plates. It deforms the surfaces and either hampers further assembly or creates stress concentration regions which may fail during operations. Yoshida wrinkling test is considered as one good tool to analyse the wrinkling properties of sheet metals. Alluminium alloys are most commonly used in aviation industry where wrinkling initiation and its propagation is considered an even serious defect. Present research was therefore focussed on Finite Element simulations of Allumium Alloy-5456-H116 metal sheets specimens of the standard shape of Yoshida specimen. During simulations the applied load values were equal to Yield strength, yield strength +10%, and Yield strength -10%. Wrinkling initiation and propagation was observed as deformations along X,Y and Z axis on a predefined path of the specimen and stress values at this path were also evaluated. Findings have been established through an overview of deformation along each axis corresponding to stress values at that location on the path.

Finite Element Analysis of a Polymer- Polymer Sliding Contact for Schallamach Wave and Wear

2007 ◽  
Vol 348-349 ◽  
pp. 633-636 ◽  
Author(s):  
Muhammad Azeem Ashraf ◽  
Bijan Sobhi-Najafabadi ◽  
Özdemir Göl ◽  
D. Sugumar
Keyword(s):  
Finite Element ◽  
Polymer Surface ◽  
Sliding Contact ◽  
Quasi Steady State ◽  
Nodal Solutions ◽  
Element Analysis ◽  
Steady State Analysis ◽  
Initiation And Propagation ◽  
Wear Law ◽  
Nodal Level

Sliding polymer-polymer surface contacts, due to their inherent elastic properties, exhibit detachment waves also termed as Schallamach waves. Such waves effect the initiation and propagation of wear along the sliding contacts. This paper presents quasi steady-state analysis of such a sliding contact using finite element. The contact is modeled and nodal solutions for pressure are obtained for small sliding steps. Analysis of orthogonal pressure components at the contact nodes reveals the formation of Schallamach wave phenomenon. Further, appropriate wear law is used for calculation of wear at nodal level.

Stress and Fatigue Life Modeling of Cannon Breech Closures Including Effects of Material Strength and Residual Stress

2000 ◽  
Vol 123 (1) ◽  
pp. 150-154
Author(s):  
John H. Underwood ◽  
Michael J. Glennon
Keyword(s):  
Residual Stress ◽  
Finite Element ◽  
Fatigue Life ◽  
Yield Strength ◽  
Residual Stresses ◽  
Solid Mechanics ◽  
Element Model ◽  
Pressure Vessels ◽  
Material Strength ◽  
Element Analysis

Laboratory fatigue life results are summarized from several test series of high-strength steel cannon breech closure assemblies pressurized by rapid application of hydraulic oil. The tests were performed to determine safe fatigue lives of high-pressure components at the breech end of the cannon and breech assembly. Careful reanalysis of the fatigue life tests provides data for stress and fatigue life models for breech components, over the following ranges of key parameters: 380–745 MPa cyclic internal pressure; 100–160 mm bore diameter cannon pressure vessels; 1040–1170 MPa yield strength A723 steel; no residual stress, shot peen residual stress, overload residual stress. Modeling of applied and residual stresses at the location of the fatigue failure site is performed by elastic-plastic finite element analysis using ABAQUS and by solid mechanics analysis. Shot peen and overload residual stresses are modeled by superposing typical or calculated residual stress distributions on the applied stresses. Overload residual stresses are obtained directly from the finite element model of the breech, with the breech overload applied to the model in the same way as with actual components. Modeling of the fatigue life of the components is based on the fatigue intensity factor concept of Underwood and Parker, a fracture mechanics description of life that accounts for residual stresses, material yield strength and initial defect size. The fatigue life model describes six test conditions in a stress versus life plot with an R2 correlation of 0.94, and shows significantly lower correlation when known variations in yield strength, stress concentration factor, or residual stress are not included in the model input, thus demonstrating the model sensitivity to these variables.

Modelling and Experimental Comparison of Fluid Structure Coupling for Thin Sheet Metal Tanks Using Statistical Energy Analysis

2016 ◽  
Author(s):  
Ketan V. Shende ◽  
Richard Keltie
Keyword(s):  
Finite Element ◽  
Sheet Metal ◽  
Energy Analysis ◽  
Thin Sheet ◽  
Broad Band ◽  
Vibration Response ◽  
Experimental Comparison ◽  
Statistical Energy Analysis ◽  
Fluid Structure ◽  
Thin Sheet Metal

Acoustic response of flat surfaces in contact with a fluid volume is of some interest for the design of automotive fuel tanks, fluid containers and underwater applications [1]. As this response can be related to the surface vibration response in the linear domain, the effect of fluid structure coupling on the vibration response of the structure is studied in this paper. Advances in the computational abilities have increased the focus of analysis-led approaches in the design of thin sheet metal tanks. Conventional finite element (FE) based approaches are useful at low frequencies but are highly sensitive to geometrical details and local effects at higher frequencies. With changing input parameters, finite element approaches could prove to be computationally expensive during the initial design phase of such structures. Statistical Energy Analysis (SEA) is an energy based approach and was used to study the fluid structure coupling effect on the vibration characteristics of a simple rectangular parallelepiped thin sheet metal tank. A thin steel tank (thickness/min. characteristic dimension <0.01) was excited by a broad band uniform power spectral density white noise signal and the spatial and frequency averaged acceleration responses were compared. Some parameters like the damping loss factor and the excitation force were calculated from the experimental measurements and used as input for SEA simulations. Coupling loss factors were calculated from tests and the trend lines were found to be in agreement with the theoretical calculations. The SEA simulation model results were compared with the conventional FE based approach for reference. Variance studies were used to compute the envelope for the SEA simulation response for a 90% confidence interval. The SEA and the test results comparison was quantified by a correlation coefficient which indicated a moderately strong correlation (>0.5) between the SEA and experimental results.

Dynamic Characteristics of a Micro-Sheet-Forming Machine System

2012 ◽  
Vol 504-506 ◽  
pp. 599-604 ◽  
Author(s):  
Yi Qin ◽  
Akhtar Razul Razali ◽  
Mei Zhou ◽  
Jie Zhao ◽  
Colin Harrison ◽  
...  
Keyword(s):  
Sheet Metal ◽  
Dynamic Characteristics ◽  
Dynamic Performance ◽  
Thin Sheet ◽  
Sheet Forming ◽  
Element Analysis ◽  
Machine System ◽  
Micro Parts ◽  
Thin Sheet Metal ◽  
Tooling System

Dynamic characteristics of a micro-forming machine system are of significant importance to be considered if high-precision micro-parts are to be produced. This is because forming tolerances may be within a range of sub-microns up to 5-15% of the thickness of a thin sheet-metal (e.g. <100µm) being used in micro-sheet-forming. Achievability of the quality parts often vary with the machine-system performance and process parameters being set, and it largely depends on the understanding of the machine and tool system’s dynamic characteristics and effectiveness of the control of the machine and the process. Nevertheless, there has been lack of the effort in this field of research. Significant number of the efforts in this field were focused mainly on discrete and/slow processes where the dynamic characteristics of the forming systems were often neglected. This paper presents the dynamic characteristics of an autonomous micro-sheet-forming machine system and its effect towards the produced parts’ quality. These have been studied by combining finite element analysis and forming experiment, with a particular focus on the combined effects from the machine, tooling system and the sheet-metal feeding system (the strip feeder). The results showed that, besides importance of the dynamic performance of the machine and the tool-system, dynamic characteristics of the material-feeding plays an important part in determining the parts’ quality produced.

Finite Element Analysis of Tensile Test for HDPE/EPR-MMT Nanocomposite

2015 ◽  
Vol 1115 ◽  
pp. 414-417
Author(s):  
N.M. Shaffiar ◽  
M.K.A. Halim ◽  
H. Anuar ◽  
M.A.H.A. Majid
Keyword(s):  
Finite Element ◽  
Tensile Strength ◽  
Ultimate Tensile Strength ◽  
Yield Strength ◽  
Tensile Test ◽  
Tensile Loading ◽  
Nanocomposite Material ◽  
Percentage Error ◽  
Material Strength ◽  
Element Analysis

A small amount of nanodispersed filler leads to an improvement in material properties. Montmorillonite (MMT) is one type of filler commonly used in nanocomposite material. A high density polyethylene/ethylene propylene rubber - montmorillonite (HDPE/EPR-MMT) is one of the nanocomposite material that is new to the industry. This paper investigates the strength of HDPE/EPR-MMT nanocomposite under tensile loading. The experimental results of the tensile test on the nanocomposite will be compared with the tensile simulation in the Finite Element (FE) analysis for validation. The results showed that it is validated with relatively low percentage error of 0.01 % for the ultimate tensile strength and 0.18 % for the yield strength. The ultimate tensile strength of HDPE/EPR-MMT is 14.5 MPa and the yield strength is 13.2 MPa. By using MMT as a filler, the material strength is improved. The ultimate tensile strength of HDPE/EPR without filler is 11.45 MPa and the yield strength is 10.95 MPa.

scholarly journals Biomechanics of subtrochanteric fracture fixation using short cephalomedullary nails: A finite element analysis

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0253862
Author(s):  
Dae-Kyung Kwak ◽  
Sun-Hee Bang ◽  
Won-Hyeon Kim ◽  
Sung-Jae Lee ◽  
Seunghun Lee ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Yield Strength ◽  
Cortical Bone ◽  
Osteoporotic Bone ◽  
Element Analysis ◽  
Distal Locking ◽  
Normal Bone ◽  
Locking Screws ◽  
Cephalomedullary Nails

A finite element analysis was performed to evaluate the stresses around nails and cortical bones in subtrochanteric (ST) fracture models fixed using short cephalomedullary nails (CMNs). A total 96 finite element models (FEMs) were simulated on a transverse ST fracture at eight levels with three different fracture gaps and two different distal locking screw configurations in both normal and osteoporotic bone. All FEMs were fixed using CMNs 200 mm in length. Two distal locking screws showed a wider safe range than 1 distal screw in both normal and osteoporotic bone at fracture gaps ≤ 3 mm. In normal bone FEMs fixed even with two distal locking screws, peak von Mises stresses (PVMSs) in cortical bone and nail constructs reached or exceeded 90% of the yield strength at fracture levels 50 mm and 0 and 50 mm, respectively, at all fracture gaps. In osteoporotic bone FEMs, PVMSs in cortical bone and nail constructs reached or exceeded 90% of the yield strength at fracture levels 50 mm and 0 and 50 mm, respectively, at a 1-mm fracture gap. However, at fracture gaps ≥ 2 mm, PVMSs in cortical bone reached or exceeded 90% of the yield strength at fracture levels ≥ 35 mm. PVMSs in nail showed the same results as 1-mm fracture gaps. PVMSs increased and safe range reduced, as the fracture gap increased. Short CMNs (200 mm in length) with two distal screws may be considered suitable for the fixation of ST transverse fractures at fracture levels 10 to 40 mm below the lesser trochanter in normal bone and 10 to 30 mm in osteoporotic bone, respectively, under the assumptions of anatomical reduction at fracture gap ≤ 3 mm. However, the fracture gap should be shortened to the minimum to reduce the risk of refracture and fixation failure, especially in osteoporotic fractures.

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