Methodology improvement of bulk compressive creep test: Deformation measurement and loading rate

He, Ying; Chen, Cuiting; Yan, Yixin; Swain, Michael V.; Li, Qiulan; Jian, Yutao; Zhao, Kang; Wang, Xiaodong

doi:10.1016/j.dental.2022.07.008

Cited by 2 publications

(2 citation statements)

References 30 publications

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“…Creep indentation distance is a measure of how much the bone deforms under a constant load over time ( 40 ), and a decrease in creep indentation distance indicates that the bone is better able to resist deformation. Similarly, an increase in average unloading slope indicates that the bone is able to better recover its shape after being deformed, which also suggests a lower risk of microdamage ( 41 ). Although, CHC decreased the bone’s ability to absorb impacts and increased susceptibility to microdamage, but it retained the ability to repair microdamage and withstand cyclic loading, indicating that a decrease in mineralization likely impaired the bone’s mechanical properties under static loading, but not its ability to withstand cyclic loading over time.…”

Section: Discussionmentioning

confidence: 99%

Hormonal and non-hormonal oral contraceptives given long-term to pubertal rats differently affect bone mass, quality and metabolism

Porwal,

Sharma,

Kumar

et al. 2023

Front. Endocrinol.

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IntroductionWe investigated the effects of hormonal and non-hormonal oral contraceptives (OCs) on bone mass, mineralization, composition, mechanical properties, and metabolites in pubertal female SD rats.MethodsOCs were given for 3-, and 7 months at human equivalent doses. The combined hormonal contraceptive (CHC) was ethinyl estradiol and progestin, whereas the non-hormonal contraceptive (NHC) was ormeloxifene. MicroCT was used to assess bone microarchitecture and BMD. Bone formation and mineralization were assessed by static and dynamic histomorphometry. The 3-point bending test, nanoindentation, FTIR, and cyclic reference point indentation (cRPI) measured the changes in bone strength and material composition. Bone and serum metabolomes were studied to identify potential biomarkers of drug efficacy and safety and gain insight into the underlying mechanisms of action of the OCs.ResultsNHC increased bone mass in the femur metaphysis after 3 months, but the gain was lost after 7 months. After 7 months, both OCs decreased bone mass and deteriorated trabecular microarchitecture in the femur metaphysis and lumbar spine. Also, both OCs decreased the mineral: matrix ratio and increased the unmineralized matrix after 7 months. After 3 months, the OCs increased carbonate: phosphate and carbonate: amide I ratios, indicating a disordered hydroxyapatite crystal structure susceptible to resorption, but these changes mostly reversed after 7 months, indicating that the early changes contributed to demineralization at the later time. In the femur 3-point bending test, CHC reduced energy storage, resilience, and ultimate stress, indicating increased susceptibility to micro-damage and fracture, while NHC only decreased energy storage. In the cyclic loading test, both OCs decreased creep indentation distance, but CHC increased the average unloading slope, implying decreased microdamage risk and improved deformation resistance by the OCs. Thus, reduced bone mineralization by the OCs appears to affect bone mechanical properties under static loading, but not its cyclic loading ability. When compared to an age-matched control, after 7 months, CHC affected 24 metabolic pathways in bone and 9 in serum, whereas NHC altered 17 in bone and none in serum. 6 metabolites were common between the serum and bone of CHC rats, suggesting their potential as biomarkers of bone health in women taking CHC.ConclusionBoth OCs have adverse effects on various skeletal parameters, with CHC having a greater negative impact on bone strength.

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Section: Discussionmentioning

confidence: 99%

Hormonal and non-hormonal oral contraceptives given long-term to pubertal rats differently affect bone mass, quality and metabolism

Porwal,

Sharma,

Kumar

et al. 2023

Front. Endocrinol.

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“…The set-up of SPCRT is similar to the SPT, but changing the testing steps to adapt it to a typical creep-recovery test [ 27 ]: (i) firstly, the specimen is punched with a controlled straining until reaching a punch displacement of 0.10 mm (loading step); (ii) the reached load at this displacement is fixed during a prescribed time (creep step); (iii) the specimen is unloaded with a controlled displacement (unloading step); and (iv), the time-dependent displacement recovery is registered in the absence of loading (recovery step). Figure 2 shows the punch displacement evolution along test time.…”

Section: Introductionmentioning

confidence: 99%

Application of the Small Punch Creep-Recovery Test (SPCRT) for the Estimation of Large-Amplitude Viscoelastic Properties of Polymers

et al. 2023

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The Small Punch Creep-Recovery Test (SPCRT) is a novel miniature test used to estimate the viscoelastic properties of polymers and biomaterials. The current investigation related to the SPCRT is limited to Finite Element Method (FEM) simulations and experimental tests on PVC. The aim of this investigation was focused on: (i) extending the experimental tests to other polymers with dissimilar viscoelastic properties; (ii) deepening the influence of non-linear viscoelastic properties in the estimation capabilities of the SPCRT; and (iii) developing a numerical methodology to estimate and take into account the viscoelastic recovery produced during the unloading step of compressive creep-recovery tests (CCRT) and SPCRTs. The experimental tests (CCRTs and SPCRTs) were done on polyethylene PE 500, polyoxymethylene POM C, nylon PA 6, and polytetrafluoroethylene (PTFE), with a range of creep loads, in the case of CCRTs, in the whole elastic regime and the surroundings of the yield strength of each material. The experimental results confirmed that the SPCRT was an accurate and reliable testing method for linear viscoelastic polymers. For a non-linear viscoelastic behavior, SPCRT estimated the viscoelastic properties obtained from CCRTs for creep loads near the yield strength of the polymer, which corresponded with large-amplitude viscoelastic properties in dynamic creep testing. In order to consider the viscoelastic recovery generated in the unloading step of CCRTs and SPCRTs, a Maxwell-Wiechert model with two branches was used, simulating the different steps of the experimental tests, and solving numerically the differential equation of the Maxwell-Wiechert model with the Runge-Kutta-Fehlberg (RKF) numerical method. The coefficients of the elements of the Maxwell-Wiechert model were estimated approaching the straining curve of the recovery step of the simulation with the same curve registered on each experimental test. Experimental CCRTs with different unloading times demonstrated that the use of this procedure derived in no influence of the unloading step time in the viscoelastic properties estimation.

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Methodology improvement of bulk compressive creep test: Deformation measurement and loading rate

Cited by 2 publications

References 30 publications

Hormonal and non-hormonal oral contraceptives given long-term to pubertal rats differently affect bone mass, quality and metabolism

Hormonal and non-hormonal oral contraceptives given long-term to pubertal rats differently affect bone mass, quality and metabolism

Application of the Small Punch Creep-Recovery Test (SPCRT) for the Estimation of Large-Amplitude Viscoelastic Properties of Polymers

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