Effect of Ramp Angle on the Anti-Loosening Ability of Wedge Self-Locking Nuts Under Vibration

2018 ◽  
Vol 140 (7) ◽  
Author(s):  
Jianhua Liu ◽  
Hao Gong ◽  
Xiaoyu Ding
Keyword(s):  
Finite Element ◽  
Numerical Simulations ◽  
Production Technology ◽  
Material Properties ◽  
Threshold Value ◽  
Commercial Production ◽  
Experimental Results ◽  
Fe Method ◽  
Transversal Vibration

Recently, the wedge self-locking nut, a special anti-loosening product, is receiving more attention because of its excellent reliability in preventing loosening failure under vibration conditions. The key characteristic of a wedge self-locking nut is the special wedge ramp at the root of the thread. In this work, the effect of ramp angle on the anti-loosening ability of wedge self-locking nuts was studied systematically based on numerical simulations and experiments. Wedge self-locking nuts with nine ramp angles (10 deg, 15 deg, 20 deg, 25 deg, 30 deg, 35 deg, 40 deg, 45 deg, and 50 deg) were modeled using a finite element (FE) method, and manufactured using commercial production technology. Their anti-loosening abilities under transversal vibration conditions were analyzed based on numerical and experimental results. It was found that there is a threshold value of the initial preload below which the wedge self-locking nuts would lose their anti-loosening ability. This threshold value of initial preload was then proposed for use as a criterion to evaluate the anti-loosening ability of wedge self-locking nuts quantitatively and to determine the optimal ramp angle. Based on this criterion, it was demonstrated, numerically and experimentally, that a 30 deg wedge ramp resulted in the best anti-loosening ability among nine ramp angles studied. The significance of this study is that it provides an effective method to evaluate the anti-loosening ability of wedge self-locking nuts quantitatively, and determined the optimal ramp angle in terms of anti-loosening ability. The proposed method can also be used to optimize other parameters, such as the material properties and other dimensions, to guarantee the best anti-loosening ability of wedge self-locking nuts.

scholarly journals Influence of Material Properties on Automobile Energy-Absorbing Components Crashworthiness

2014 ◽  
Vol 8 (1) ◽  
pp. 113-116
Author(s):  
Liuyan Jie ◽  
Ding Lin
Keyword(s):  
Finite Element ◽  
Numerical Simulations ◽  
Material Properties ◽  
Simulation Analysis ◽  
Fe Method ◽  
Thin Walled Tube ◽  
Thin Walled ◽  
Energy Absorbing

In the present work, the simulation analysis of automobile energy-absorbing components was carried out using Finite Element (FE) method. The numerical simulations were carried out using the software LS-DYNA. Automobile energy-absorbing components usually were made of a metal thin walled tube. In the paper, several types of material properties were studied and compared. Results show that the material properties have influence to automobile energy - absorbing components crashworthiness.

Determination of Charge Coefficient of Piezoelectric Films Using a Combined Finite Element Model and Dynamic Loading Technique

2020 ◽  
Vol 835 ◽  
pp. 229-242
Author(s):  
Oboso P. Bernard ◽  
Nagih M. Shaalan ◽  
Mohab Hossam ◽  
Mohsen A. Hassan
Keyword(s):  
Finite Element ◽  
Dynamic Loading ◽  
Material Properties ◽  
Accurate Determination ◽  
Substrate Material ◽  
Experimental Results ◽  
Piezoelectric Composite ◽  
Piezoelectric Film ◽  
Piezoelectric Charge

Accurate determination of piezoelectric properties such as piezoelectric charge coefficients (d33) is an essential step in the design process of sensors and actuators using piezoelectric effect. In this study, a cost-effective and accurate method based on dynamic loading technique was proposed to determine the piezoelectric charge coefficient d33. Finite element analysis (FEA) model was developed in order to estimate d33 and validate the obtained values with experimental results. The experiment was conducted on a piezoelectric disc with a known d33 value. The effect of measuring boundary conditions, substrate material properties and specimen geometry on measured d33 value were conducted. The experimental results reveal that the determined d33 coefficient by this technique is accurate as it falls within the manufactures tolerance specifications of PZT-5A piezoelectric film d33. Further, obtained simulation results on fibre reinforced and particle reinforced piezoelectric composite were found to be similar to those that have been obtained using more advanced techniques. FE-results showed that the measured d33 coefficients depend on measuring boundary condition, piezoelectric film thickness, and substrate material properties. This method was proved to be suitable for determination of d33 coefficient effectively for piezoelectric samples of any arbitrary geometry without compromising on the accuracy of measured d33.

scholarly journals Analytic analysis of auxetic metamaterials through analogy with rigid link systems

2018 ◽  
Vol 474 (2210) ◽  
pp. 20170753 ◽  
Author(s):  
Daniel Rayneau-Kirkhope ◽  
Chengzhao Zhang ◽  
Louis Theran ◽  
Marcelo A. Dias
Keyword(s):  
Finite Element ◽  
Mechanical Behaviour ◽  
Material Properties ◽  
Threshold Value ◽  
Finite Element Simulations ◽  
Elastic Instability ◽  
Lattice Systems ◽  
Rigid Link ◽  
Post Buckling ◽  
Insight Into

In recent years, many structural motifs have been designed with the aim of creating auxetic metamaterials. One area of particular interest in this subject is the creation of auxetic material properties through elastic instability. Such metamaterials switch from conventional behaviour to an auxetic response for loads greater than some threshold value. This paper develops a novel methodology in the analysis of auxetic metamaterials which exhibit elastic instability through analogy with rigid link lattice systems. The results of our analytic approach are confirmed by finite-element simulations for both the onset of elastic instability and post-buckling behaviour including Poisson’s ratio. The method gives insight into the relationships between mechanisms within lattices and their mechanical behaviour; as such, it has the potential to allow existing knowledge of rigid link lattices with auxetic paths to be used in the design of future buckling-induced auxetic metamaterials.

On the Use of the Theory of Critical Distances to Estimate KIc and ∆Kth from Experimental Results Generated by Testing Standard Notches

2009 ◽  
Vol 417-418 ◽  
pp. 25-28
Author(s):  
Luca Susmel ◽  
David Taylor
Keyword(s):  
Fatigue Limit ◽  
Material Properties ◽  
Reliable Method ◽  
Threshold Value ◽  
Experimental Results ◽  
Plane Strain Fracture Toughness ◽  
Linear Elastic ◽  
Experimental Strategy ◽  
Strain Fracture ◽  
Elastic Fracture

The present paper is concerned with the use of the Theory of Critical Distances (TCD), applied in the form of the Point Method (PM), to estimate the range of the threshold value of the stress intensity factor, Kth, as well as the plane strain fracture toughness, KIc. In more detail, by reanalysing a large amount of experimental data taken from the literature, it is proved that Kth can successfully be evaluated through the plain fatigue limit and another fatigue limit generated by testing samples containing a known geometrical feature, whereas KIc is suggested here as being estimated by using experimental results generated by testing samples weakened by notches of different sharpness. The validation exercise summarised in the present paper fully confirms that the TCD is not only a reliable method suitable for performing the static and fatigue assessment of real components, but also an efficient experimental strategy capable of accurately estimating the classical Linear Elastic Fracture Mechanics (LEFM) material properties.

Finite Element Analysis of Composite Flywheel with Two-Layer Pre-Stressed Rotor Structure

2011 ◽  
Vol 488-489 ◽  
pp. 134-137
Author(s):  
Zheng Yi Ren ◽  
Jing Na Liu ◽  
Qing Fen Li ◽  
Ke Fei Li
Keyword(s):  
Finite Element ◽  
Plane Stress ◽  
Material Properties ◽  
Circumferential Stress ◽  
Fe Method ◽  
Element Analysis ◽  
Composite Flywheel ◽  
Flywheel Rotors ◽  
Main Dimension ◽  
Rotor Structure

In this paper, considering the material properties of the composite flywheel and the characteristics of the pre-stressed structure, stresses and strains induced by rotor rotation and interference fit were calculated by finite element (FE) method based on the plane stress hypothesis, in the commercial software ANSYS. Based on the given material properties and the main dimension with a certain speed of rotation, three 2D FE-models of hybrid composite flywheel rotors with two-layer rotor structure were built with the unit property of plane stress, axisymmetric and plane strain respectively. Followed, the radial stress, circumferential stress and radial displacement of the rotor were obtained. The three simulation results are almost accordant with the present theoretical results. It shows that the numerical analyses are reliable. It can be shown that is advisable to design and optimize the flywheel rotor.

A Study on the Nanoindentation Behaviour of Single Crystal Silicon Using Hybrid MD-FE Method

2008 ◽  
Vol 32 ◽  
pp. 259-262 ◽  
Author(s):  
Akbar Afaghi Khatibi ◽  
Bohayra Mortazavi
Keyword(s):  
Molecular Dynamics ◽  
Finite Element ◽  
Single Crystal ◽  
Material Properties ◽  
Single Crystal Silicon ◽  
Dynamics Simulation ◽  
Fe Method ◽  
Crystal Silicon ◽  
Element Analysis ◽  
Nano Scale

Developing new techniques for the prediction of materials behaviors in nano-scales has been an attractive and challenging area for many researches. Molecular Dynamics (MD) is the popular method that is usually used to simulate the behavior of nano-scale material. Considering high computational costs of MD, however, has made this technique inapplicable as well as inflexible in various situations. To overcome these difficulties, alternative procedures are thought. Considering its capabilities, Finite Element Analysis (FEA) seems to be the most appropriate substitute for MD simulations in most cases. But since the material properties in nano, micro, and macro scales are different, therefore to use FEA methods in nano-scale modeling one must use material properties appropriate to that scale. To this end, a previously developed Hybrid Molecular Dynamics-Finite Element (HMDFE) approach was used to investigate the nanoindentation behavior of single crystal silicon with Berkovich indenter. In this study, a FEA model was developed based on the material properties extracted from molecular dynamics simulation of uniaxial tension test on single crystal Silicon. Eventually, by comparison of FEA results with experimental data, the validity of this new technique for the prediction of nanoindentation behavior of Silicon was concluded.

Development of a customized density—modulus relationship for use in subject-specific finite element models of the ulna

2009 ◽  
Vol 223 (6) ◽  
pp. 787-794 ◽  
Author(s):  
R L Austman ◽  
J S Milner ◽  
D W Holdsworth ◽  
C E Dunning
Keyword(s):  
Finite Element ◽  
Cortical Bone ◽  
Material Properties ◽  
Beam Theory ◽  
Average Density ◽  
Experimental Results ◽  
Finite Element Models ◽  
Theory Analysis ◽  
Distal Ulna ◽  
Subject Specific

Assigning an appropriate density—modulus relationship is an important factor when applying inhomogeneous material properties to finite element models of bone. The purpose of this study was to develop a customized density—modulus equation for the distal ulna, using beam theory combined with experimental results. Five custom equations of the form E = aρb were used to apply material properties to models of eight ulnae. All equations passed through a point (1.85, Ec), where ρ = 1.85 g/cm3 represents the average density of cortical bone. For custom equations (1) to (3), Ec was predicted using beam theory, and the value of b was varied within the range reported in the literature. Custom equations (4) and (5) used other values of Ec from the literature, while keeping b constant. Results obtained from the custom equations were compared with those from other equations in the literature, and with experimental results. The beam theory analysis predicted Ec = 21 ± 1.6 GPa, and the three custom equations using this value tended to have the lowest errors. The power of the equations did not affect the results as much as the value used for Ec. Overall, a customized density—modulus relationship for the ulna was generated, which provided improved results over using previously reported density—modulus equations.

Nanoindentation on a Ni Nanodot-Patterned Surface

2008 ◽  
Author(s):  
Hengyu Wang ◽  
Min Zou ◽  
Robert L. Jackson ◽  
Preston R. Larson ◽  
Matthew B. Johnson
Keyword(s):  
Finite Element ◽  
Numerical Simulations ◽  
Experimental Results ◽  
Spherical Contact ◽  
Patterned Surface ◽  
Size And Shape ◽  
Ordered Arrays ◽  
Simulation Results ◽  
Good Agreement

Nanoindentation on a Ni nanodot-patterned surface (NDPS) was investigated experimentally and numerically. The Ni NDPS consists of well-ordered arrays of Ni nanodots with approximately the same size and shape. The nanoindentation experiments were performed on the Ni NDPS using diamond tips of 1 and 5 μm radii of curvature. To efficiently simulate large number of nanodots in contact, numerical simulations were carried out using formulae empirically fitted from a finite element (FE) study of a single spherical contact. The simulation results were found to be in good agreement with the experimental results.

Comparing Methods for Establishing Multiscale Material Properties of 0.2 mm Thick Annealed ASTM 304

2015 ◽  
Author(s):  
William J. Emblom ◽  
Md. F. S. Ibne Islam ◽  
Richard J. Jones ◽  
Mitra Aithal ◽  
Scott Wagner ◽  
...  
Keyword(s):  
Finite Element ◽  
Sheet Metal ◽  
Material Properties ◽  
Strain Measurement ◽  
Measurement Errors ◽  
Element Model ◽  
Experimental Results ◽  
304 Stainless Steel ◽  
Membrane Theory ◽  
Forming Process

Producing fuel cells bipolar plates and other devices such as microscale heat exchangers for electronics requires both macroscale and microscale forming processes. At the macroscale, typically, mechanical properties of sheet metal are determined by performing tensile tests. In addition, it has long been recognized that bi-axial tension tests, dome tests, and hydroforming or viscous bulge tests provide the basis for improved understanding of the mechanics of sheet metal forming. At the microscale strain gauges are too large for measuring strains in small regions and membrane theory is only valid at the poles of the bulge. Continuum mechanics models are useful but require tedious thickness measurements for multiple work pieces, requiring extensive sample preparation and analysis. In this paper experimental results from hydroforming tests for 0.2-mm thick annealed ASTM 304 stainless steel sheet in 11 mm, 5 mm, and 1 mm diameter open dies at various pressures were evaluated. The height of the bulge at the pole and strains based upon measurements of 127 micron strain grids were determined. These dies represent the transition from a small macroscale process to a microscale forming process. Two methods were used to estimate material properties: an analytical model and an iterative method which compared experimental strain results with the strains from a finite element model where the Holloman constitutive properties of the sheet were varied. The problems estimating material properties based upon grid strain measurement, membrane theory, and the iterative finite element approaches were investigated and the results were compared. This study indicates that membrane theory will provide adequate predictions for Holloman constructive properties provided the assumptions for membrane theory are not violated. However, using measured microscale grid deformation strains does not produce very good agreement estimates of the Holloman constitutive model when comparing experimental results with FEA strains. It is believed that while the grid strain measurement method used results in strain measurement errors of less than 1.5% of strain, this error is sufficient to result in enough uncertainty to produce results that are inconsistent with other methods.

Finite Element Simulation of Hot Forging Process for KVBM Gear

2018 ◽  
Vol 875 ◽  
pp. 30-35 ◽  
Author(s):  
Sethapong Wangchaichune ◽  
Surasak Suranuntchai
Keyword(s):  
Finite Element ◽  
Plastic Strain ◽  
Effective Stress ◽  
Hot Forging ◽  
Experimental Results ◽  
Effective Plastic Strain ◽  
Fe Method ◽  
Modeling And Analysis ◽  
Forging Process ◽  
Initial Billet

In this study, the forging operations of gear has been modeled. This gear is a part which is manufactured with the help of hot forging industry for reduce the cost. The authors propose to reduce the initial billet volume of AISI 4340 steel for the forged through process optimization using the Finite Element (FE)method. The object of this research was to predict the effect of several parameters, such as effective stress, effective plastic strain, temperature and die contact, on the forming of the gear, utilizing computer simulation and experimental results. For this purpose, Solidworks CAD and Simufact Forming FE software were used for the modeling and analysis of the forging process. The billet volume and the preform design were predefined in order to reduce scrap by using preform type C. The experimental results showed that the initial billet volume was reduced at 32 %, which compared favorably with the simulation result of a 40 % reduction. The maximum preforming force of simulation result was diferent with the experiment result at 18 along with the maximum finishing force of simulation result was different with the experiment result at 11 %. It was also found that the effective stress decreased with increasing the temperature, and the press force decreased when the initial billet volume was decreased, which resulted in a decrease of effective plastic strain as well.

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