Wide-range linear viscoelastic hydrogels with high mechanical properties and their applications in quantifiable stress-strain sensors

Epoxy resin-based composite panels used for armors may be subjected to a wide range of operating temperatures (-55°C to 76°C) and high strain rates on the order of 103-104 s-1. Over the life cycle, various environmental factors also affect the resin properties and hence influence the performance of the composites. Therefore, it is critical to determine the stress-strain behavior of the epoxy resin over a wide range of strain rates and temperatures for accurate multi-scale modeling of composites and to investigate the influence of environmental aging on the resin properties. Additionally, the characterization of key mechanical properties such as yield stress, modulus, and energy absorption (i.e. area under the stress-strain curve) at varying temperatures and moisture can provide critical data to calculate the material operating limits. In this study, we characterize mechanical properties of neat epoxy resin, SC-15 (currently used in structural armor) and RDL-RDC using uniaxial compression testing. RDL-RDC, developed by Huntsman Corporation, has a glass transition temperature of ~ 120°C, compared to ~ 85°C of SC-15. A split Hopkinson pressure bar is used for high strain rate testing. Quasistatic testing is conducted using a screw-driven testing machine (Instron 4484) at 10-3 s-1 and 10-1 s-1 strain rates and varying temperatures. The yield stress is fit to a modified Eyring model over the varying strain rates at room temperature. For rapid investigation of resistance to environmental aging, accelerated aging tests are conducted by immersing the specimens in 100°C water for 48 hours. Specimens are conditioned in an environmental chamber at 76 °C and 88% RH until they reach equilibrium. Tests are then conducted at five different temperatures from 0°C to 95°C, and key mechanical properties are then plotted vs. temperature. The results presented are an important step towards developing a methodology to identify environmental operating conditions for composite ground vehicle applications.

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Mechanical Properties and Stress-Strain Behaviour of Binary and Ternary Composites Based on Polyolefins and Vegetable Fillers

Solid State Phenomena ◽

10.4028/www.scientific.net/ssp.265.221 ◽

2017 ◽

Vol 265 ◽

pp. 221-226 ◽

Cited By ~ 13

Author(s):

E.E. Mastalygina ◽

A.A. Popov

Keyword(s):

Mechanical Properties ◽

Filler Content ◽

Low Density Polyethylene ◽

Biological Degradation ◽

Stress Strain ◽

Strain Behaviour ◽

Composition And Structure ◽

Study Results ◽

Wide Range ◽

Dimensional Parameters

Binary and ternary composites based on isotactic polypropylene and low-density polyethylene in a wide range of ratios without and with filler content have been investigated. Micron-scale vegetable cellulosic components initiating biological degradation have been used as fillers for polymeric composites. The analysis of stress-strain behaviour of the composites has shown a non-additive dependency of elongation and tensile strength at break on blends composition. Based on this study results the composition and structure of polymeric phase of binary and ternary composites, as well as dimensional parameters of filler particles have a significant impact on stress-strain behaviour of the materials. The main regularities determining materials mechanical properties have been discovered, that, in turn, could be used for predicting service behaviour of composites under investigation.

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High Strain Rate Mechanical Properties of SAC-Q Between -65°C and +200°C After Exposure to Isothermal Aging

ASME 2020 International Technical Conference and Exhibition on Packaging and Integration of Electronic and Photonic Microsystems ◽

10.1115/ipack2020-2660 ◽

2020 ◽

Author(s):

Pradeep Lall ◽

Vishal Mehta ◽

Jeff Suhling ◽

Ken Blecker

Keyword(s):

Mechanical Properties ◽

Strain Rate ◽

Isothermal Aging ◽

High Strain ◽

Strain Rates ◽

Solder Alloys ◽

Stress Strain ◽

Wide Range ◽

Operating Temperatures ◽

Electronic Parts

Abstract In many industries, such as automotive, oil and gas, aerospace, medical technologies, electronic parts can often be exposed to high strain loads during shocks, vibrations and drop-impact conditions. Such electronic parts can often be subjected to extreme low and high temperatures ranging from −65°C to 200°C. Also, these electronic devices can be subjected to strain rates of 1 to 100 per second in the critical environment. Recently, many doped SAC solder alloys are being introduced in the electronic component including SAC-Q, SAC-R, Innolot. SAC-Q is made with addition of Bi in Sn-Ag-Cu composition. Mechanical characteristic results and data for lead-free solder alloys are extremely important for optimizing electronic package reliability, at high temperature storage and elevated strain rates. Furthermore, the mechanical properties of solder alloys can be changed significantly due to a thermal aging, which is causing modification of microstructure. Data for the SAC-Q solder alloy with a high temp aging and testing at extreme low to high operating temperatures are not available. SAC-Q material was tested and analyzed for this study at range of operating temperatures of −65°C to 200°C and at a strain rate up to 75 per second. After the specimens were manufactured and reflowed, specimens were stored at 100°C for the isothermal aging for up to 90 days, before tensile tests were carried out at different operating temperatures. For the wide range of strain rates and test temperatures, stress-strain curves are established. In addition, the measured experimental results and data were fitted to the Anand viscoplasticity model and the Anand constants were calculated by estimating the stress-strain behavior measured in the wide range of operating temperatures and strain rates.

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The Influence of Redundant Work When Drawing Rods Through Conical Dies

Journal of Engineering for Industry ◽

10.1115/1.3604653 ◽

1968 ◽

Vol 90 (2) ◽

pp. 411-416 ◽

Cited By ~ 18

Author(s):

R. M. Caddell ◽

A. G. Atkins

Keyword(s):

Mechanical Properties ◽

Strain Hardening ◽

Stress Strain ◽

Work Factor ◽

Wide Range ◽

Before And After

Values of the redundant work factor in rod drawing were determined experimentally for four metals over a wide range of variables; none of the metals were strain hardened prior to drawing. The method of superposition of stress-strain curves before and after drawing was used, and an expression for the redundant work factor was found to be related to the strain hardening characteristics of the metal being drawn. Use of this factor was made to predict certain mechanical properties of the drawn metals; these agreed quite well with the values measured experimentally.

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Novel Ring Compression Test Method to Determine the Stress-strain Relations and Mechanical Preperties of Metallic Materials

10.21203/rs.3.rs-139258/v1 ◽

2021 ◽

Author(s):

Guang-Zhao Han ◽

lixun Cai ◽

Chen Bao ◽

Bo Liang ◽

Yang Lv ◽

...

Keyword(s):

Mechanical Properties ◽

Test Method ◽

Metallic Materials ◽

Compression Tests ◽

Stress Strain ◽

Element Analysis ◽

Strain Relation ◽

Stress Strain Relation ◽

Ring Compression ◽

Wide Range

Abstract Although there are methods for testing the stress–strain relation and strength, which are the most fundamental and important properties of metallic materials, their application to small size specimens is limited. In this study, a new dimensionless elastoplastic load–displacement (EPLD-Ring) model for compressed metal rings with isotropy and constitutive power law is proposed to describe the relation between the geometric dimensions, Hollomon law parameters, load, and displacement based on energy density equivalence. Furthermore, a novel test method for the rings is developed to obtain the elastic modulus, stress–strain relation, yield strength, and tensile strength. The universality and accuracy of the model are verified within a wide range of imaginary materials via finite element analysis (FEA), and the results show that the stress–strain relations obtained with the model are more consistent with those inputted in the FEA software. Additionally, for seven metallic materials, a series of ring compression tests with various dimensions were performed. It was found that the stress–strain relations and mechanical properties predicted by the model are in agreement with the normal tensile test results. It is believed that the new method is reliable and effective for testing the mechanical properties of small size materials and tube components.

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Effects of Cyclic Freezing and Thawing on the Shear Behaviors of an Expansive Soil under a Wide Range of Stress Levels

10.21203/rs.3.rs-507911/v1 ◽

2021 ◽

Author(s):

Wei-lie Zou ◽

Zhong Han ◽

Gui-tao Zhao ◽

Kewei Fan ◽

Sai K. Vanapalli ◽

...

Keyword(s):

Mechanical Properties ◽

Strain Softening ◽

Expansive Soil ◽

Friction Angle ◽

Shearing Stress ◽

Freezing And Thawing ◽

Confining Stress ◽

Stress Strain ◽

Apparent Cohesion ◽

Wide Range

Abstract The focus of this paper is directed towards investigating the influence of multiple freeze-thaw (FT) cycles on the stress-strain relationships during undrained shearing for an expansive soil under a wide range of confining stresses (σc) from 0 to 300 kPa. Different numbers of FT cycles were applied to compacted specimens. The influence of FT cycles on the soil’s structure was investigated using mercury intrusion porosimetry (MIP) and scanning electron microscope (SEM) tests. FT impacted specimens were subjected to consolidated undrained (CU) shear tests with pore pressure measurement (σc = 10 to 300 kPa) and unconfined compression (UC) tests (σc = 0 kPa) to derive the shearing stress-strain relationships and the associated mechanical properties including (i) failure strength (qu), elastic modulus (Eu), effective and apparent cohesion (c’ and c), and effective and apparent friction angle (ϕ’ and ϕ) obtained from CU tests and (ii) qu and reloading modulus (E1%) and stress (Su1%) at 1% strain obtained from UC tests. Testing results show that FT cycles mainly influence the soil’s macropores with diameters between 5 and 250 microns. Cracks develop during FT cycles and result in slight swelling which contributes to an increase in the global volume of the soil specimens. There is a significant reduction in the investigated mechanical properties after FT cycles. They typically achieve equilibrium after about 6 cycles. The shearing stress-strain curves transits from strain-softening to strain-hardening as the confining stress increases. An empirical model is developed to describe the strain-softening behavior of the specimens under low confining stresses. The model is simple to use and well describes all stress-strain curves obtained in this study that show strain-softening characteristics.

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Mechanical Properties and Dislocation Structure of Single Crystal Cdte Deformed in Compression at 300°C

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010009292x ◽

1976 ◽

Vol 34 ◽

pp. 592-593

Author(s):

Ernest L. Hall ◽

J. B. Vander Sande

Keyword(s):

Mechanical Properties ◽

Single Crystal ◽

Dislocation Structure ◽

Room Temperature ◽

Elevated Temperatures ◽

Strain Curve ◽

Optical Devices ◽

Semiconductor Compound ◽

Wide Range ◽

Sample Orientation

The present paper describes research on the mechanical properties and related dislocation structure of CdTe, a II-VI semiconductor compound with a wide range of uses in electrical and optical devices. At room temperature CdTe exhibits little plasticity and at the same time relatively low strength and hardness. The mechanical behavior of CdTe was examined at elevated temperatures with the goal of understanding plastic flow in this material and eventually improving the room temperature properties. Several samples of single crystal CdTe of identical size and crystallographic orientation were deformed in compression at 300°C to various levels of total strain. A resolved shear stress vs. compressive glide strain curve (Figure la) was derived from the results of the tests and the knowledge of the sample orientation.

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Impact of physical and mechanical properties of materials being joined on the formation of stress-strain state in the joint in diffusion welding

Collection of Scientific Publications NUS ◽

10.15589/jnn20140403 ◽

2014 ◽

Vol 0 (4) ◽

Author(s):

Viktor V. Kvasnytskyi ◽

Maksym V. Matvienko

Keyword(s):

Mechanical Properties ◽

Strain State ◽

Physical And Mechanical Properties ◽

Diffusion Welding ◽

Stress Strain ◽

Stress Strain State ◽

Mechanical Properties Of Materials ◽

Properties Of Materials

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Structure and properties of compact articles from high-alloyed iron powder with adding of boron nitride

Perspektivnye Materialy ◽

10.30791/1028-978x-2020-8-39-48 ◽

2020 ◽

pp. 39-48

Author(s):

B. O. Bolshakov ◽

◽

R. F. Galiakbarov ◽

A. M. Smyslov ◽

◽

...

Keyword(s):

Mechanical Properties ◽

Boron Nitride ◽

Grain Boundary ◽

Bending Strength ◽

Physical And Mechanical Properties ◽

Operating Conditions ◽

Structure And Properties ◽

Steam Turbines ◽

Friction Forces ◽

Wide Range

The results of the research of structure and properties of a composite compact from 13 Cr – 2 Мо and BN powders depending on the concentration of boron nitride are provided. It is shown that adding boron nitride in an amount of more than 2% by weight of the charge mixture leads to the formation of extended grain boundary porosity and finely dispersed BN layers in the structure, which provides a high level of wearing properties of the material. The effect of boron nitride concentration on physical and mechanical properties is determined. It was found that the introduction of a small amount of BN (up to 2 % by weight) into the compacts leads to an increase in plasticity, bending strength, and toughness by reducing the friction forces between the metal powder particles during pressing and a more complete grain boundary diffusion process during sintering. The formation of a regulated structure-phase composition of powder compacts of 13 Cr – 2 Mо – BN when the content of boron nitride changes in them allows us to provide the specified physical and mechanical properties in a wide range. The obtained results of studies of the physical and mechanical characteristics of the developed material allow us to reasonably choose the necessary composition of the powder compact for sealing structures of the flow part of steam turbines, depending on their operating conditions.

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