Experimental Setup for the Determination of Mechanical Solder Materials Properties at Elevated Temperatures

2010 ◽  
Vol 638-642 ◽  
pp. 3793-3798
Author(s):  
Wolfgang H. Müller ◽  
Holger Worrack ◽  
Jens Sterthaus
Keyword(s):  
Mechanical Properties ◽  
Young’S Modulus ◽  
Elevated Temperatures ◽  
Young's Modulus ◽  
Linear Optimization ◽  
Strain Curve ◽  
Stress And Strain ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Non Linear

The fabrication of microelectronic and micromechanical devices leads to the use of only very small amounts of matter, which can behave quite differently than the corresponding bulk. Clearly, the materials will age and it is important to gather information on the (changing) material characteristics. In particular, Young’s modulus, yield stress, and hardness are of great interest. Moreover, a complete stress-strain curve is desirable for a detailed material characterization and simulation of a component, e.g., by Finite Elements (FE). However, since the amount of matter is so small and it is the intention to describe its behavior as realistic as possible, miniature tests are used for measuring the mechanical properties. In this paper two miniature tests are presented for this purpose, a mini-uniaxial-tension-test and a nanoindenter experiment. In the tensile test the axial load is prescribed and the corresponding extension of the specimen length is recorded, both of which determines the stress-strain- curve directly. The stress-strain curves are analyzed by assuming a non-linear relationship between stress and strain of the Ramberg-Osgood type and by fitting the corresponding parameters to the experimental data (obtained for various microelectronic solders) by means of a non-linear optimization routine. For a detailed analysis of very local mechanical properties nanoindentation is used, resulting primarily in load vs. indentation-depth data. According to the procedure of Oliver and Pharr this data can be used to obtain hardness and Young’s modulus but not a complete stress-strain curve, at least not directly. In order to obtain such a stress-strain-curve, the nanoindentation experiment is combined with FE and the coefficients involved in the corresponding constitutive equations for stress and strain are obtained by means of the inverse method. The stress-strain curves from nanoindentation and tensile tests are compared for two mate-rials (aluminum and steel). Differences are explained in terms of the locality of the measurement. Finally, material properties at elevated temperature are of particular interest in order to characterize the materials even more completely. We describe the setup for hot stage nanoindentation tests in context with first results for selected materials.

scholarly journals Effect of Nanopores on Mechanical Properties of the Shape Memory Alloy

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 529
Author(s):  
Chunzhi Du ◽  
Zhifan Li ◽  
Bingfei Liu
Keyword(s):  
Mechanical Properties ◽  
Constitutive Model ◽  
Shape Memory ◽  
Young’S Modulus ◽  
Residual Strain ◽  
Surface Effect ◽  
Young's Modulus ◽  
Strain Curve ◽  
Stress Strain ◽  
Strength Limit

Nanoporous Shape Memory Alloys (SMA) are widely used in aerospace, military industry, medical and health and other fields. More and more attention has been paid to its mechanical properties. In particular, when the size of the pores is reduced to the nanometer level, the effect of the surface effect of the nanoporous material on the mechanical properties of the SMA will increase sharply, and the residual strain of the SMA material will change with the nanoporosity. In this work, the expression of Young’s modulus of nanopore SMA considering surface effects is first derived, which is a function of nanoporosity and nanopore size. Based on the obtained Young’s modulus, a constitutive model of nanoporous SMA considering residual strain is established. Then, the stress–strain curve of dense SMA based on the new constitutive model is drawn by numerical method. The results are in good agreement with the simulation results in the published literature. Finally, the stress-strain curves of SMA with different nanoporosities are drawn, and it is concluded that the Young’s modulus and strength limit decrease with the increase of nanoporosity.

Polysilicon Tensile Testing With Electrostatic Gripping

1998 ◽  
Vol 518 ◽  
Author(s):  
W. N. Sharpe ◽  
K. Turner ◽  
R. L. Edwards
Keyword(s):  
North Carolina ◽  
Young’S Modulus ◽  
Tensile Testing ◽  
Young's Modulus ◽  
Strain Curve ◽  
Electrostatic Forces ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Force Displacement

AbstractTechniques and procedures are described for tensile testing of polysilicon specimens that are 1.5 or 3.5 νm thick and have various widths and lengths. The specimens are fixed to the wafer at one end and have a large free end that can be gripped by electrostatic forces. This enables easy handling and testing and permits the deposition of 18 specimens on a one-centimeter square portion of a wafer. The displacement of the free end is monitored, which allows one to extract Young's modulus from the force-displacement record. Some of the wider specimens have two gold lines applied so that strain can be measured interferometrically directly on the specimen to record a stress-strain curve.The specimens were produced at the Microelectronics Center of North Carolina (MCNC). When compared with earlier results of wider MCNC specimens that were 3.5 μm thick, the Young's modulus is smaller and the strength is slightly larger.

Molecular dynamics simulations of the effect of temperature and strain rate on the plastic deformation of body centred cubic iron nanowires

2021 ◽  
pp. 1-19
Author(s):  
Qian Wu ◽  
Yong Wang ◽  
Tao Han ◽  
Hongtao Wang ◽  
Laihui Han ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Plastic Deformation ◽  
Strain Rate ◽  
Yield Stress ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Strain Curve ◽  
Dislocation Slip ◽  
Stress Strain Curve ◽  
Stress Strain

Abstract The tensile tests of BCC Fe nanowires were simulated through molecular dynamics methods. The temperature and strain rate effects on the mechanical properties as well as the orientation-dependent plastic deformation mechanism were analyzed. For [001]-oriented BCC Fe nanowires, as the temperature increased, the yield stress and Young's modulus decreased. While the yield stress and Young's modulus increased as the strain rate increased. With the increase of temperature, when the temperature was less than 400 K, the twin propagation stress decreased dramatically, and then tended to reach a saturation value at higher temperatures. Under different temperatures and strain rates, the [001]-oriented Fe nanowires all deformed by twinning. The oscillation stage in the stress-strain curve corresponds to the process from the nucleation of the twin to the reorientation of the nanowire. For [110]-oriented Fe nanowires, the plastic deformation is dominated by dislocation slip. The independent events such as the nucleation, slip, and annihilation of dislocations are the causes of the unsteady fluctuations in the stress-strain curve. The Fe nanowires eventually undergo shear damage along the dominant slip surface.

Design and Manufacture of a Smart Macro-Structure with Changeable Effective Stiffness

2020 ◽  
Vol 12 (01) ◽  
pp. 2050001
Author(s):  
Mohammad Reza Hajighasemi ◽  
Majid Safarabadi ◽  
Azadeh Sheidaei ◽  
Mostafa Baghani ◽  
Majid Baniassadi
Keyword(s):  
Young’S Modulus ◽  
Periodic Structure ◽  
Young's Modulus ◽  
Strain Curve ◽  
Unit Cell ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Fused Deposition ◽  
Nonlinear Stress ◽  
A Cell

Smart materials are being utilized in many fields and different external stimuli are used to change specific properties of these materials. In this research, a novel method was developed to design a structure with the desired nonlinear effective Young’s modulus. This method is geometric based where the structures are designed with a gap between them. These structures exhibit nonlinear elastic response. Wide range of structures with desired stress–strain curve can be generated using this approach. First, a unit cell was designed and later used to create a periodic structure. Numerical simulations have been exploited to prove the efficiency of the method. A prototype was manufactured by the Fused Deposition Modeling (FDM) 3D printing method. The compression test was performed on the structure. Both simulations and experimental results proved that the effective Young’s modulus of the structure can be increased up to 142%. Second, the designed unit cell was optimized using Genetic Algorithm (GA) to achieve a cell with desired nonlinear stress–strain curve. This cell was optimized considering five effective geometric parameters to alter the effective Young’s modulus of the cell. Finally, a periodic structure was created by repeating a cell with two different gap’s distances. A structure with a desired stress–strain curve was designed using the same method.

scholarly journals Developing a Quantifying Device for Soft Tissue Material Prop-Erties around Lumbar Spines

Biosensors ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 67
Author(s):  
Song Joo Lee ◽  
Yong-Eun Cho ◽  
Kyung-Hyun Kim ◽  
Deukhee Lee
Keyword(s):  
Lumbar Spine ◽  
Soft Tissue ◽  
Young’S Modulus ◽  
Viscoelastic Properties ◽  
Soft Tissues ◽  
Young's Modulus ◽  
Strain Curve ◽  
Stress And Strain ◽  
Commercial Device ◽  
Tissue Material

Knowing the material properties of the musculoskeletal soft tissue could be important to develop rehabilitation therapy and surgical procedures. However, there is a lack of devices and information on the viscoelastic properties of soft tissues around the lumbar spine. The goal of this study was to develop a portable quantifying device for providing strain and stress curves of muscles and ligaments around the lumbar spine at various stretching speeds. Each sample was conditioned and applied for 20 repeatable cyclic 5 mm stretch-and-relax trials in the direction and perpendicular direction of the fiber at 2, 3 and 5 mm/s. Our device successfully provided the stress and strain curve of the samples and our results showed that there were significant effects of speed on the young’s modulus of the samples (p < 0.05). Compared to the expensive commercial device, our lower-cost device provided comparable stress and strain curves of the sample. Based on our device and findings, various sizes of samples can be measured and viscoelastic properties of the soft tissues can be obtained. Our portable device and approach can help to investigate young’s modulus of musculoskeletal soft tissues conveniently, and can be a basis for developing a material testing device in a surgical room or various lab environments.

Numerical Modeling of Macroscopic Behavior of Particulate Composite with Crosslinked Polymer Matrix

2011 ◽  
Vol 465 ◽  
pp. 129-132
Author(s):  
Luboš Náhlík ◽  
Bohuslav Máša ◽  
Pavel Hutař
Keyword(s):  
Young’S Modulus ◽  
Polymer Matrix ◽  
Young's Modulus ◽  
Numerical Models ◽  
Strain Curve ◽  
Particulate Composite ◽  
Material Behavior ◽  
Particulate Composites ◽  
Stress Strain ◽  
Crosslinked Polymer

Particulate composites with crosslinked polymer matrix and solid fillers are one of important classes of materials such as construction materials, high-performance engineering materials, sealants, protective organic coatings, dental materials, or solid explosives. The main focus of a present paper is an estimation of the macroscopic Young’s modulus and stress-strain behavior of a particulate composite with polymer matrix. The particulate composite with a crosslinked polymer matrix in a rubbery state filled by an alumina-based mineral filler is investigated by means of the finite element method. A hyperelastic material behavior of the matrix was modeled by the Mooney-Rivlin material model. Numerical models on the base of unit cell were developed. The numerical results obtained were compared with experimental stress-strain curve and value of initial Young’s modulus. The paper can contribute to a better understanding of the behavior and failure of particulate composites with a crosslinked polymer matrix.

Mechanical properties of UN-5100 envelope material for stratospheric airship

2020 ◽  
pp. 1-17
Author(s):  
W.-c. Xie ◽  
X.-l. Wang ◽  
D.-p. Duan ◽  
J.-w. Tang ◽  
Y. Wei
Keyword(s):  
Mechanical Properties ◽  
Significant Role ◽  
Strain Curve ◽  
Image Correlation ◽  
Membrane Structures ◽  
Stress Strain Curve ◽  
Stress Strain ◽  
Biaxial Tensile ◽  
Envelope Material ◽  
Biaxial Tensile Testing

ABSTRACT Stratospheric airships are promising aircraft, usually designed as a non-rigid airship. As an essential part of the non-rigid airship, the envelope plays a significant role in maintaining its shape and bearing the external force load. Generally, the envelope material of a flexible airship consists of plain-weave fabric, composed of warp and weft fibre yarn. At present, biaxial tensile experiments are the primary method used to study the stress–strain characteristics of such flexible airship materials. In this work, biaxial tensile testing of UN-5100 material was carried out. The strain on the material under unusual stress and the stress ratio were obtained using Digital Image Correlation (DIC) technology. Also, the stress–strain curve was corrected by polynomial fitting. The slope of the stress–strain curve at different points, the Membrane Structures Association of Japan (MSAJ) standard and the Radial Basis Function (RBF) model were compared to identify the stress–strain characteristics of the materials. Some conclusions on the mechanical properties of the flexible airship material can be drawn and will play a significant role in the design of such envelopes.

Effect of temperature on properties of aluminum/single-walled carbon nanotube nanocomposite by molecular dynamics simulation

2019 ◽  
Vol 234 (2) ◽  
pp. 635-642 ◽  
Author(s):  
Mohsen Motamedi ◽  
AH Naghdi ◽  
SK Jalali
Keyword(s):  
Mechanical Properties ◽  
Molecular Dynamics ◽  
Carbon Nanotube ◽  
Molecular Dynamics Simulation ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Strain Curve ◽  
Dynamics Simulation ◽  
Effect Of Temperature ◽  
Metal Composite

Composite materials have become popular because of high mechanical properties and lightweight. Aluminum/carbon nanotube is one of the most important metal composite. In this research, mechanical properties of aluminum/carbon nanotube composite were obtained using molecular dynamics simulation. Then, effect of temperature on stress–strain curve of composite was studied. The results showed by increasing temperature, the Young’s modulus of composite was decreased. More specifically increasing the temperature from 150 K to 620 K, decrease the Young’s modulus to 11.7%. The ultimate stress of composite also decreased by increasing the temperature. A continuum model of composite was presented using finite element method. The results showed the role of carbon nanotube on strengthening of composite.

Uniaxial Mechanical Properties of Sandstone under Cyclic of Drying and Wetting

2011 ◽  
Vol 243-249 ◽  
pp. 2310-2313 ◽  
Author(s):  
Hua Yan Yao ◽  
Zhen Hua Zhang ◽  
Zhao Hui Zhu
Keyword(s):  
Mechanical Properties ◽  
Constitutive Model ◽  
Young’S Modulus ◽  
Young's Modulus ◽  
Test Results ◽  
Stress Strain ◽  
Deformation And Failure ◽  
Deformation Behaviors ◽  
Uniaxial Strength

Water is an important factor that influences the mechanical properties of rock. Uniaxial compressive experiments have been carried out on sandstone under different cyclic times of drying and wetting. The corresponding complete stress-strain curves are obtained, and characteristics of deformation and failure are analyzed. Test results show that when sandstone samples are submitted to cyclic of drying and wetting, the uniaxial strength and Young's modulus of sandstone obviously decrease. Then, the improved Duncan constitutive model is developed, which can do better in describing sample’s deformation behaviors subject to different cyclic times of drying and wetting. Introduction

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