Stiffness based technique to probe cyclic damage accumulation in micro-structurally graded bond coats via micro-beam bending tests

Background: The purpose of this study was to evaluate the risk of peri-prosthetic fracture of constructs made with cephalomedullary (CM) long and short nails. The nails were made with titanium alloy (Ti-6Al-4V) and stainless steel (SS 316L).Methods: Biomechanical evaluation of CM nail constructs was carried out with regard to post-primary healing to determine the risk of peri-implant/peri-prosthetic fractures. Therefore, this research comprised of, non-fractured, twenty-eight pairs of cadaveric femora that were randomized and implanted with four types of fixation CM nails resulting in four groups. These constructs were cyclically tested in bi-axial mode for up to 30,000 cycles. All the samples were then loaded to failure to measure failure loads. Three frameworks were carried out through this investigation, Michaelis–Menten, phenomenological, and probabilistic Monte Carlo simulation to model and predict damage accumulation.Findings: Damage accumulation resulting from bi-axial cyclic loading in terms of construct stiffness was represented by Michaelis–Menten equation, and the statistical analysis demonstrated that one model can explain the damage accumulation during cyclic load for all four groups of constructs (P > 0.05). A two-stage stiffness drop was observed. The short stainless steel had a significantly higher average damage (0.94) than the short titanium nails (0.90, P < 0.05). Long titanium nail group did not differ substantially from the short stainless steel nails (P > 0.05). Results showed gender had a significant effect on load to failure in both torsional and bending tests (P < 0.05 and P < 0.001, respectively).Interpretation: Kaplan–Meier survival analysis supports the use of short titanium CM nail. We recommend that clinical decisions should take age and gender into consideration in the selection of implants.

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Interlaminar Tensile Strength of CFRP Composites Reinforced With Interleaved Carbon Nanotube Sheets

Volume 14: Emerging Technologies; Engineering Management, Safety, Ethics, Society, and Education; Materials: Genetics to Structures ◽

10.1115/imece2014-38876 ◽

2014 ◽

Author(s):

Benjamin L. Levy-Wendt ◽

Alaina M. Bever ◽

Nicholaus C. Wright ◽

Timothy J. Venable ◽

John P. Dally ◽

...

Keyword(s):

Tensile Strength ◽

Carbon Nanotube ◽

Carbon Fiber ◽

Composite Laminates ◽

Specimen Thickness ◽

Curved Beam ◽

Bending Tests ◽

Reinforced Polymer ◽

Cfrp Composites ◽

Beam Bending

Unidirectional carbon-fiber-reinforced polymer (CFRP) composites with interleaved carbon nanotube (CNT) sheets were manufactured using a heated press. The effect of CNT sheets on the interlaminar tensile strength (ILTS) of composite laminates was measured using curved beam bending tests. Two sets of [0]24 T800S/3900-2B specimen were prepared using carbon fiber prepregs and non-woven CNT sheets, with specimen thickness and radial geometries conforming to ASTM D6415. Epoxy resin loaded CNT sheets were inserted in the mid-radius region of curved beam specimens during the lay-up process. The measured interlaminar tensile strengths (ILTS) were compared between the CNT-enhanced and baseline CFRP specimens. Specimen fracture surfaces were examined with optical microscopy to determine the mode of failure and to confirm that fracture occurred at the location with the highest radial stresses. CNT sheet enhancements have shown to improve ILTS by 42%, with all failures initiating at the CNT interlayer and the polymer matrix interface.

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A phenomenological life evaluation method for corrosion fatigue

Corrosion Reviews ◽

10.1515/corrrev-2016-0063 ◽

2017 ◽

Vol 35 (2) ◽

pp. 75-83

Author(s):

Shanqin Hou ◽

Jinquan Xu

Keyword(s):

Stress State ◽

Corrosion Fatigue ◽

Damage Accumulation ◽

Evaluation Method ◽

High Stress ◽

Corrosion Damage ◽

Cyclic Fatigue ◽

Life Evaluation ◽

Fatigue Damage Accumulation ◽

Cyclic Damage

AbstractConsidering interacted damage accumulations induced by corrosion, cyclic fatigue, and stress corrosion cracking, a phenomenological corrosion fatigue (CF) life evaluation formula has been proposed. A concept of nominal CF limit has been introduced, which indicates whether cyclic damage accumulation is active or not. It is found that cyclic fatigue damage accumulation enhanced by corrosion is the dominative damage under relatively high stress amplitudes (compared to the nominal limit), whereas, under low stress amplitudes, corrosion damage accumulation would become the dominative one. Stress amplitudes below the nominal fatigue limit would lead to CF too due to corrosion damage accumulation, which can finally make the effective amplitude larger than nominal limit. Once the parameters included in formula have been determined by uniaxial tests, CF life under any complicated stress state could be estimated in a unified way.

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Evaluation of pharmaceutical beam bending tests using double-exposure holographic interferometry

European Journal of Pharmaceutics and Biopharmaceutics ◽

10.1016/s0939-6411(97)00135-5 ◽

1997 ◽

Vol 44 (3) ◽

pp. 261-267 ◽

Cited By ~ 4

Author(s):

P Raatikainen

Keyword(s):

Holographic Interferometry ◽

Double Exposure ◽

Bending Tests ◽

Beam Bending ◽

Double Exposure Holographic Interferometry

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Creep Bending Tests of Large Weld Overlay and Base Metal Specimens at 1000°F (537.7°C)

Journal of Pressure Vessel Technology ◽

10.1115/1.3454306 ◽

1975 ◽

Vol 97 (4) ◽

pp. 264-269

Author(s):

I. Berman ◽

R. Henschel

Keyword(s):

Finite Element Analysis ◽

Base Metal ◽

Primary Creep ◽

Creep Tests ◽

Element Analysis ◽

Bending Tests ◽

Weld Overlay ◽

Beam Bending ◽

Short Time ◽

Book Values

One thousand-hr beam bending creep tests at 1000° F (537.7° C) on four, one-in. (25.4-mm) deep stainless steel specimens of seven-in. gage length with constant end moment were run. The specimens included: two of all weld metal, one of base metal and one bimetallic beam. The short time and creep bending results are compared to the results of a finite element analysis in which book values are used. The experimental results indicate some significant differences in short time properties and primary creep. The analytical results substantially underestimate the primary creep.

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New Method to Determine Young’s Modulus of Micro Crystal Based on Raman Spectrometer

Defect and Diffusion Forum ◽

10.4028/www.scientific.net/ddf.272.1 ◽

2008 ◽

Vol 272 ◽

pp. 1-6

Author(s):

Sheng Bo Sang

Keyword(s):

Mechanical Properties ◽

Young’S Modulus ◽

Young's Modulus ◽

Frequency Measurement ◽

High Accuracy ◽

Tension Test ◽

Bulge Test ◽

Bending Tests ◽

Beam Bending

With the development of MEMS, the mechanical properties of micro crystals must to be determined to know the defect, reliability and characterization of MEMS. Young’s modulus is one of the most important properties, which indicates the ability of resisting the elastic deformation. Many methods, such as natural frequency measurement, beam bending tests, membrane bulge test and uniaxial tension test, have been used to measure Young’s modulus of Si, SiN and metals. But there are some limitations when they are used to measure micro crystals in MEMS. This paper puts forward a high accuracy and convenient method----using Raman spectrum to measure Young’s modulus of micro crystals in MEMS, and sets up the measurement system. Measured Young’s modulus of Si and GaAs in [100] crystallographic orientation are 161.113GPa and 84.128GPa respectively, which correspond with the Yong’s modulus in common use now. Based on the values, it can be analyzed if there are some defects in the micro crystals.

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Mechanical testing of limpet teeth micro-beams using FIB

MRS Proceedings ◽

10.1557/proc-1274-qq08-07 ◽

2010 ◽

Vol 1274 ◽

Author(s):

Dun Lu ◽

Asa H Barber

Keyword(s):

Mechanical Testing ◽

Focused Ion Beam ◽

Fibre Composite ◽

Ion Beam ◽

Bending Tests ◽

Tooth Structure ◽

Force Microscopy ◽

Atomic Force ◽

Beam Bending ◽

Mechanical Bending

AbstractDiscrete volumes of material in the form of a beam have been isolated from a parent limpet tooth using Focused Ion Beam (FIB) techniques. Mechanical bending tests of individual beams are performed using atomic force microscopy (AFM). The relatively small volumes tested in this beam-bending configuration allow approximation of the limpet tooth structure to a uniaxial short fibre composite. This mechanical testing technique is superior to conventional micro-hardness indentation as a defined stress condition within a locally defined volume is examined. Composite theory is shown to be valid for describing the mechanical properties of limpet teeth at sub-micron lengths scales and used to determine the synergy between the nanomaterial constituents.

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Acoustic emission data analyses based on crumb rubber concrete beam bending tests

Engineering Fracture Mechanics ◽

10.1016/j.engfracmech.2018.05.016 ◽

2019 ◽

Vol 210 ◽

pp. 189-202 ◽

Cited By ~ 17

Author(s):

Qinghua Han ◽

Guang Yang ◽

Jie Xu ◽

Zhengwu Fu ◽

Giuseppe Lacidogna ◽

...

Keyword(s):

Acoustic Emission ◽

Concrete Beam ◽

Crumb Rubber ◽

Emission Data ◽

Bending Tests ◽

Data Analyses ◽

Beam Bending ◽

Crumb Rubber Concrete ◽

Rubber Concrete

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An Instrument for Measuring Mechanical Properties of MEMS Materials by Nanoindentation and Micro-Beam-Bending

First International Conference on Integration and Commercialization of Micro and Nanosystems, Parts A and B ◽

10.1115/mnc2007-21421 ◽

2007 ◽

Author(s):

Hairong Wang ◽

Zexiang Zhao ◽

Zhuangde Jiang ◽

R. Du

Keyword(s):

Mechanical Properties ◽

Bending Test ◽

Nanoindentation Test ◽

Small Displacement ◽

Maximum Output ◽

Bending Tests ◽

Output Displacement ◽

Second Stage ◽

Stage System ◽

Beam Bending

This paper presents an instrument for measuring the mechanical properties of MEMS materials by both nanoindentation and micro-beam-bending tests. The nanoindentation test requires high resolution within a very small displacement range, whereas the micro-beam-bending test needs relatively large displacement range but lower resolution. Though, for both tests, loading with small increment is necessary. In order to satisfy different requirements and yet save cost, a two-stage system driven by a PZT actuator in the first stage and by a DC-Mike Linear motor in the second stage is designed and built. The instrument achieves a displacement resolution better than 1 nm within a range of 50 microns in the first stage and the maximum output displacement is over 1 mm in the second stage. The measurement accuracy is validated through experiments.

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