Estimation Of Stiffness Research Articles

An image-based approach for the estimation of arterial local stiffness in vivo.

The analysis of mechanobiology of arterial tissues remains an important topic of research for cardiovascular pathologies evaluation. In the current state of the art, the gold standard to characterize the tissue mechanical behavior is represented by experimental tests, requiring the harvesting of ex-vivo specimens. In recent years though, image-based techniques for the in vivo estimation of arterial tissue stiffness were presented. The aim of this study is to define a new approach to provide local distribution of arterial stiffness, estimated as the linearized Young's Modulus, based on the knowledge of in vivo patient-specific imaging data. In particular, the strain and stress are estimated with sectional contour length ratios and a Laplace hypothesis/inverse engineering approach, respectively, and then used to calculate the Young's Modulus. After describing the method, this was validated by using a set of Finite Element simulations as input. In particular, idealized cylinder and elbow shapes plus a single patient-specific geometry were simulated. Different stiffness distributions were tested for the simulated patient-specific case. After the validation from Finite Element data, the method was then applied to patient-specific ECG-gated Computed Tomography data by also introducing a mesh morphing approach to map the aortic surface along the cardiac phases. The validation process revealed satisfactory results. In the simulated patient-specific case, root mean square percentage errors below 10% for the homogeneous distribution and below 20% for proximal/distal distribution of stiffness. The method was then successfully used on the three ECG-gated patient-specific cases. The resulting distributions of stiffness exhibited significant heterogeneity, nevertheless the resulting Young's moduli were always contained within the 1-3MPa range, which is in line with literature.

Risk-averse estimates of effective properties in heterogeneous elasticity

In this work, we propose a theoretical framework for computing pessimistic and optimistic estimates of effective properties in the case of heterogeneous elastic materials with uncertain microscopic elastic properties. We rely on a risk-averse measure widely used in finance called the conditional-value at risk (CVaR). The CVaR computes the conditional expectation of events occurring above a given risk level, thereby characterizing the extreme tails of the probability distribution of a random variable. In the context of elastic materials, we propose to use the CVaR on the elastic free energy to compute an optimistic estimate of the global stiffness for some confidence level α. Similarly, we also use the CVaR on the complementary elastic energy to compute a pessimistic estimate of the global stiffness. The obtained CVaR estimates benefit from a convex optimization formulation. The resulting material behavior is still elastic but not necessarily linear anymore. We discuss approximate formulations recovering a linear elastic behavior. We apply the proposed formulations to the micromechanical estimates of effective elastic properties of random heterogeneous materials.

Estimation of anisotropic properties of CMR patient-specific left ventricle using the virtual field method.

Left ventricle (LV) myocardial dysfunction has been recently investigated using the estimation of isotropic myocardial stiffness from magnetic resonance imaging (MRI). However, Myocardium is known to have a 3D complex geometry with anisotropic stiffness. The assessment of the anisotropy properties characterizes structural changes in myocardium as a consequence of heart failure (HF). From image data, the virtual field method (VFM) can determine material stiffness in a non-invasive manner. In the present work, the objective is to compare two inverse identification methods, given the isotropic and anisotropic models in the characterization of properties of myocardium in acute lymphoblastic leukemia (ALL) survivors using VFM and MRI. Two types of VFM approach are presented. Using the first, the virtual displacements (VFs) allow whole-field LV to be imposed into VFM formulation and caused to directly estimate two independent parameters from isotropic constitutive relation. With the second, anisotropic parameters are estimated using piece-wise (Finite element-based) VFM. The resulting values showed significant differences between the subjects in comparative study of leukemia survivors, and variance in estimated parameters by two different VFM approach. This approach would be an efficient tool to characterize early cardiac dysfunction. This work elucidates the benefits and shortcomings of using VFM to determine anisotropic parameters of LV myocardium in linear elastic and of using the FEM application to generate meshes of patient-specific LVs from MRI images.

Relationship of Arterial Stiffness and Central Hemodynamics With Cardiovascular Risk In Hypertension.

Hypertension is becoming a serious public health problem and noninvasive estimation of central hemodynamics and artery stiffness have been identified as important predictors of cardiovascular disease. The study included 4,311 participants, both sex and aged between 20 and 79 years. Arterial velocity pulse index, arterial pressure-volume index (AVI, API, and the index of artery stiffness), central systolic blood pressure, central artery pulse pressure (CSBP, CAPP, and estimated via oscillometric blood pressure monitor), and 10-year risk score of cardiovascular disease in China (China-PAR) and Framingham cardiovascular risk score (FCVRS) were assessed at baseline. Regression model was performed to identify factors associated with high cardiovascular disease risk stratification. The relationships between CSBP, CAPP and China-PAR, and FCVRS were analyzed by restrictive cubic spline functions. The uncontrolled hypertension group showed the highest values of AVI, API, CSBP, and CAPP. In the regression analysis, CAPP and hypertension subtypes were identified as significant predictors of high cardiovascular risk stratification, and CAPP was strongly correlated with API in this cohort. Finally, CSBP and CAPP showed significant J-shaped relationships with China-PAR and FCVRS. Subjects with uncontrolled hypertension present with elevated values of CAPP, CSBP, API, AVI, China-PAR, and FCVRS scores. CAPP was independently associated with high cardiovascular risk stratification, and there was a significant J-shaped relationship with China-PAR and FCVRS that may identify people with higher cardiovascular risk.

Shear Wave Elastography in Bruxism-Not Yet Ready for Clinical Routine.

Ultrasound shear wave elastography (SWE) is an emerging modality for the estimation of stiffness, but it has not been studied in relation to common disorders with altered stiffness, such as bruxism, which affects almost one-third of adults. Because this condition could lead to an increased stiffness of masticatory muscles, we investigated SWE in bruxism according to a proof-of-principle and feasibility study with 10 patients with known bruxism and an age- and gender-matched control group. SWE of the left and right masseter muscles was estimated under three conditions: relaxed jaw, 50% of the subjective maximal bite force, and maximal jaw opening. Rejecting the null hypothesis, SWE was significantly increased during relaxed jaw (bruxism 1.92 m/s ± 0.44; controls 1.66 m/s ± 0.24), whereas for maximal mouth opening, the result was vice versa increased with 2.89 m/s ± 0.93 for bruxism patients compared with 3.53 m/s ± 0.95 in the healthy control, which could be due to limited jaw movement in chronic bruxism patients (bruxism 4.46 m/s ± 1.17; controls 5.23 m/s ± 0.43). We show that SWE in bruxism is feasible and could be of potential use for diagnostics and monitoring, though we also highlight important limitations and necessary methodological considerations for future studies.

Articulatory overlap as a function of stiffness in German, English and Spanish word-initial stop-lateral clusters

Recently, Roon, Hoole, Zeroual, Du, and Gafos (2021) have offered evidence that an empirical estimate of stiffness, a parameter in the dynamics hypothesized to control the kinematics of gestures, modulates overlap in consonant clusters of Moroccan Arabic. Here, we extend the Roon et al. (2021) study in two ways. First, empirically, we broaden the assessment of the role of stiffness in overlap by examining data from three languages, largely confirming the Roon et al. results with electromagnetic articulography recordings from stop-lateral clusters spoken by German, English, and Spanish participants. Second, we examine for the first time the extent to which C1 and C2 stiffness individually, as opposed to the combined measure of stiffness difference in earlier work, contributes to overlap with the main finding being that the significant effect of stiffness difference is mainly due to C2 stiffness; C1 stiffness is not as robust as C2 stiffness in modulating overlap. These results are placed in the context of other work on articulatory and perceptual influences on inter-consonantal timing as well as in the broader context of work on the coupling between perception and action in other domains of skilled action.

Log scale rock physics modelling to study the effect of mineralogy on elastic properties of the Bakken Formation

The Bakken Formation is a geographically extensive, organic-rich, tight formation in the Williston Basin and currently serves as the second largest producer of oil in the USA. With respect to stratigraphy, the Devonian–Mississippian-age Bakken Formation typically comprises three members: the Upper (UB), Middle (MB), and Lower Bakken (LB). Lithologically, the upper and lower members of the Bakken are dominated by shales rich in organic-carbon, which act as the source rock for oil reservoirs in the Middle Bakken. The lithology of the Middle Bakken varies widely from siliciclastic to carbonates, with multiple distinct lithofacies typically being identified in the North Dakota portion of the Williston Basin. Good knowledge of the rock properties of the various Bakken members and lithofacies are a key component of their production potential.This study is a continuation of earlier rock physics modelling, which was done at core scale. Data from one well in Mountrail County was used for estimation of rock stiffness and velocities. Rock physics models were developed at log scale to obtain knowledge of formations' elastic properties across the Bakken members, as a function of porosity and pores' fluid type and geometry. Furthermore, the effect of frequency on fluid mixing type was investigated using both homogeneous and patchy models, then fluids were incorporated into the inclusion system using K-T, DEM, or Gassmann's equations. Kerogen was added to the system as a part of the inclusion in a way that fluid was embedded into the organic-matter. Critical porosity of 30% was also applied during DEM modeling to investigate the effects of kerogen being the load-bearing and rock matrix being suspended into it for case of high kerogen content in thermally immature source-rocks. The UB and LB shales, due to the presence of clay minerals, showed lower properties than MB and composed mainly of microfracture pores. Furthermore, the conversion of kerogen into hydrocarbons lowers the overall rock properties of the Bakken shales. The MB siliciclastic intervals showed to have more of intraparticle pores (primary porosity) with stiffer properties, whereas carbonate zones exhibited fracturing (secondary porosity). The rock physics models at macro and log scale complement each other and present a full picture of formations' elastic properties. The estimated stiffness and velocity properties are valuable input data for the development of and production from future wells.

Differential effect of dementia etiology on cortical stiffness as assessed by MR elastography

BackgroundAging and dementia involve the disruption of brain molecular pathways leading to the alterations in tissue composition and gross morphology of the brain. Phenotypic and biomarker overlap between various etiologies of dementia supports a need for new modes of information to more accurately distinguish these disorders. Brain mechanical properties, which can be measured noninvasively by MR elastography, represent one understudied feature that are sensitive to neurodegenerative processes. In this study, we used two stiffness estimation schemes to test the hypothesis that different etiologies of dementia are associated with unique patterns of mechanical alterations across the cerebral cortex. MethodsMR elastography data were acquired for six clinical groups including amyloid-negative cognitively unimpaired (CU), amyloid-positive cognitively unimpaired (A + CU), amyloid-positive participants with mild cognitive impairment (A + MCI), amyloid-positive participants with Alzheimer’s clinical syndrome (A + ACS), dementia with Lewy bodies (DLB), and frontotemporal dementia (FTD). Stiffness maps were computed using two neural network inversions with the objective to at least partially separate the parenchyma-specific and morphological effects of neurodegeneration on mechanical property estimates. A tissue-confined inversion algorithm was designed to obtain the best estimate of stiffness in the brain parenchyma itself, while a regionally-aware inversion algorithm was used to measure the tissue stiffness along with the surroundings. Mean stiffness of 15 bilateral gray matter cortical regions were considered for statistical analysis. First, we tested the hypothesis that cortical stiffness changes in the aging brain. Next, we tested the overall study hypothesis by first comparing stiffness in each clinical group to the CU group, and then comparing the clinical groups against one another. Finally, we assessed the spatial and statistical overlap between atrophy and stiffness changes for both inversions. ResultsCortical brain regions become softer with age for both inversions with larger effects observed using regionally-aware stiffness. Stiffness decreases in the range 0.010–0.027 kPa per year were observed. Pairwise comparisons of each clinical group with cognitively unimpaired participants demonstrated 5 statistically significant differences in stiffness for tissue-confined measurements and 19 statistically different stiffness changes for the regionally-aware stiffness measurements. Pairwise comparisons between clinical groups further demonstrated unique patterns of stiffness differences. Analysis of the atrophy-versus-stiffness relationship showed that regionally-aware stiffness measurements exhibit higher sensitivity to neurodegeneration with findings that are not fully explained by partial volume effects or atrophy. ConclusionsBoth tissue-confined and regionally-aware stiffness estimates exhibited unique and complementary stiffness differences in various etiologies of dementia. Our results suggest that mechanical alterations measured by MRE reflect both tissue-specific differences as well as environmental effects. Multi-inversion schemes in MRE may provide new insights into the relationships between neuropathology and brain biomechanics.

Estimation of Stiffness of Non-Cohesive Soil in Natural State and Improved by Fiber and/or Cement Addition under Different Load Conditions

The aim of this study was to compare the stiffness of gravelly sand under various load conditions-static conditions using the CBR test and cyclic conditions using the resilient modulus test. The tests were conducted on natural soil and soil improved by the addition of polypropylene fibers and/or 1.5% cement. The impacts of the compaction and curing time of the stabilized samples were also determined. The soil was sheared during the Mr tests, even after fiber reinforcement, so the resilient modulus value for the unbound sand could not be obtained. The cement addition improved Mr, and the curing time also had an impact on this parameter. The fiber addition increased the value of the resilient modulus. The CBR value of the compacted gravelly sand was relatively high. It increased after adding 0.1% fibers in the case of the standard compacted samples. The greater fiber addition lowered the CBR value. For the modified compacted samples, each addition of fibers reduced the CBR value reduced the CBR value. The addition of cement influenced the CBR increase, which was also affected by the compaction method and the curing time. The addition of fibers to the stabilized sample improved the CBR value. The relationship Mr=f(CBR) obtained for all data sets was statistically significant but characterized by a large error of estimate.

Physics-Informed Online Estimation of Stiffness and Shape of Soft Robotic Manipulators

Physics-Informed Online Estimation of Stiffness and Shape of Soft Robotic Manipulators

Knee Stiffness in Assistive Device Control at Quiet Stance: A Preliminary Study

The paper explores the use of knee stiffness as a parameter in the design of wearable knee assistive devices for augmenting human postural balance. The knee moment-angle relationship is utilized to estimate the quasi-stiffness of the knee. The measurement methods are carefully chosen to be non-invasive without rigid joint attachment to allow observation of unimpeded quiet stance. The relationship between identified biomechanical parameters and computed stiffness estimates is analyzed, and the resulting estimates are employed in the controller design of a stiffness-based knee assistive device. The paper also investigates the biomechanical response of the human body to the modulation of applied stiffness in the presence of varied visual stimuli. This research is a crucial first step toward designing knee-based assistive devices to enhance human postural balance in destabilizing environments.

A Head-to-Head Comparison of the Diagnostic Performance of Two Quantitative Tests of Liver Stiffness Estimation in A Cohort of Patients with Compensated Cirrhosis

A Head-to-Head Comparison of the Diagnostic Performance of Two Quantitative Tests of Liver Stiffness Estimation in A Cohort of Patients with Compensated Cirrhosis

Variable admittance time-delay control of an upper limb rehabilitation robot based on human stiffness estimation

This paper proposes a new variable admittance time-delay control strategy based on human stiffness estimation for improving the effectiveness of robot-assisted cooperative rehabilitation training. This control strategy is developed and implemented on a planar upper limb rehabilitation robot. Given the minimum-jerk-based desired trajectories of human hand position, in the developed control strategy, a time-delay approximator is utilized to estimate the external disturbances and modeling errors without exact knowledge of dynamics parameters, a sliding mode admittance controller is applied to obtained objective admittance characteristics, and an iterative optimization algorithm is used to estimate human arm stiffness and adjust human-robot interaction compliance. The closed-loop stability of the proposed control method is demonstrated via Lyapunov function theory. Experimental investigations involving ten subjects are conducted to validate the feasibility of the proposed control scheme. The experimental results show that the interaction compliance during cooperative rehabilitation training can be accurately adjusted based on selected admittance parameters and human arm stiffness, and it contributes to satisfying the specific training requirements of patients with different weakness levels and promoting the effectiveness of the robot-assisted training.

Estimation of the dynamic stiffness of railway ballast over a wide frequency range using the discrete element method

Ballast is an integral part of railways, serving as a load transfer medium between the rails and the subgrade. In analytical modeling of track dynamics, ballast is idealized as a spring with constant stiffness at all excitation frequencies, which is a reasonable assumption for studying track dynamics at low frequencies up to 100 Hz. For modeling railway noise, the frequency dependency of ballast stiffness and damping at high frequencies is of utmost importance. Since ballast is a granular material whose properties depend on the packing, density and size distribution of the particles, the discrete element method is a promising tool for determining the frequency-dependent ballast stiffness. In the current work, a novel approach is presented to determine the frequency dependency of dynamic stiffness of the ballast used by the Swiss Federal Railways, using Discrete Element Method (DEM). First, a characterization of the Hertzian contact parameters required for modeling the ballast is performed. The effectiveness of the discrete element method for modeling the dynamic behavior of the ballast is evaluated by comparing the results obtained from our calculations with experimental results obtained under two different boundary conditions. The evaluated dynamic stiffness varies significantly with the frequency of excitation, especially above 100 Hz. The validated DEM model is then used to determine the effects of preloads on the dynamic stiffness.

Indirect Estimation of Tire Pressure on Several Road Pavements via Interacting Multiple Model Approach

Generally, tire deflation results in a decrease in both handling performance and tire lifetime, and in fuel consumption increment. Therefore, the real-time knowledge of the pressure is important. Direct approaches via pressure sensors mounted on the rim of each tire are not practical, due to technical and economic reasons. Cost-effective solutions with real-time estimation of tire pressure are generally less accurate and reliable than direct ones. Dynamical estimators based on a suspension model need road surface topology information to compute disturbances on the suspension system as an input, which is typically unknown. This paper proposes an innovative approach to estimate tire pressure indirectly, without actual road surface roughness information. A vertical suspension dynamic model is used to build several unscented Kalman filters, parametrised around different road surface topologies. These estimators are combined following the Interacting Multiple Model approach, which gives an acceptable estimation of tire stiffness through a weighted average obtained from a probabilistic model. A known linear static relationship between the tire stiffness and inflation pressure is utilized to indirectly estimate the tire inflation pressure. A Monte Carlo analysis has been performed on a wide range of driving scenarios and vehicle manoeuvres. The results of the estimation have been compared to those of a single unscented Kalman filter, in order to validate the effectiveness of the proposed solution and to highlight the improved performances in monitoring tire pressure.

Investigation of the relationship between tensile viscoelasticity and unloaded ultrasound shear wave measurements in ex vivo tendon

Mechanical properties of biological tissues are of key importance for proper function and in situ methods for mechanical characterization are sought after in the context of both medical diagnosis as well as understanding of pathophysiological processes. Shear wave elastography (SWE) and accompanying physical modelling methods provide valid estimates of stiffness in quasi-linear viscoelastic, isotropic tissue but suffer from limitations in assessing non-linear viscoelastic or anisotropic material, such as tendon. Indeed, mathematical modelling predicts the longitudinal shear wave velocity to be unaffected by the tensile but rather the shear viscoelasticity. Here, we employ a heuristic experimental testing approach to the problem to assess the most important potential confounders, namely tendon mass density and diameter, and to investigate associations between tendon tensile viscoelasticity with shear wave descriptors. Small oscillatory testing of animal flexor tendons at two baseline stress levels over a large frequency range comprehensively characterized tensile viscoelastic behavior. A broad set of shear wave descriptors was retrieved on the unloaded tendon based on high frame-rate plane wave ultrasound after applying an acoustic deformation impulse. Tensile modulus and strain energy dissipation increased logarithmically and linearly, respectively, with the frequency of the applied strain. Shear wave descriptors were mostly unaffected by tendon diameter but were highly sensitive to tendon mass density. Shear wave group and phase velocity showed no association with tensile elasticity or strain rate-stiffening but did show an association with tensile strain energy dissipation.The longitudinal shear wave velocity may not characterize tensile elasticity but rather tensile viscous properties of transversely isotropic collagenous tissues.

Estimation and Adjustment of Interface Stiffnesses for Machine-Tool

This study adopts a practical approach to establish the estimation and adjustment methods of the interface stiffness for the machine-tool through the finite element analysis (FEA). First, numerical and experimental modal analysis (FMA and EMA) for each single subsystem of the machine-tool structure are performed. Then, the parameters obtained from EMA are used as the objective criterion function, and the FMA is conducted iteratively to solve the material Young’s modulus and Poisson’s ratio for each single subsystem structure, in which the geometrical model is simplified and FE mesh convergence is performed to ensure the quality and efficiency of the numerical analysis. Next, by considering that the machine-tool is assembled by subsystem stacking and that loading on each contact surface is deduced, the FE method is used to calculate the deformation of each contact interface after the single subsystem is stacked successively. The initial value of the interface stiffness estimated by the deformation formula in the mechanics of material is utilized as the initial condition for the iterative calculation in FMA. The changes of the modal parameters are observed in the analysis and the interface, which have a significant impact on the natural frequency variations of the whole machine-tool is selected as the main adjustment object. Then, the adjustment method proposed in this study is applied repeatedly to modify this interface stiffness. The results show that footing interface stiffnesses play the most important role that intensively affects the numerical analysis results of modal parameter. After the repeated adjustments of the interface stiffnesses of the footing, the error of the natural frequency of the whole machine-tool is less than 5%, which is calculated from the comparison between EMA and FMA results. It indicates that the proposed adjustment method in this study for footing interface stiffness determination has a valuable reference in practical use.

Cognitive impairment is associated with cardiovascular remodeling in the mouse model of Alzheimer’s disease

AbstractBackgroundDouble‐mutant mice (APPswe/PS1dE9; 2xTg‐AD) represent a model of Alzheimer’s disease (AD). 2xTg‐AD mice develop progressive accumulation of amyloid plaques and cognitive impairment (CI) with age in >12 months old animals. The aim of the present study was to investigate the associations of CI and cardiovascular function in 2xTg‐AD mice.MethodsAortic pulse wave velocity (aPWV), an estimation of aortic stiffness, and cardiac parameters were measured by echocardiography in 16‐mo old male 2xTg‐AD (n=11) and wild type (WT; n=17) mice. Spatial memory (using Morris water maze; MWM) and the anxiety level (using open field test; OFT) were assessed. The relationship between cardiovascular and behavioral parameters were modeled using a linear regression analysis (LRA) with a backward elimination. P‐values <0.05 were considered significant, and 0.05≤P<0.1 were considered near significant and were included in the models.Results2xTg‐AD mice exhibited an increase in aPWV and had a thicker left ventricle (LV) posterior wall in diastole (LVPWd) and narrower LV internal diameter (LVIDd) vs. WT mice (Table 1). 2xTg‐AD mice spent less time in the center of OF vs. WT mice (Table 1). LRA revealed a negative association between time spent in the center of OF and LVPWd, and a positive association with LV volume in diastole (LVvold) in 2xTg‐AD mice (Table 2). In MWM, 2xTg‐AD mice exhibited impaired spatial memory estimated as prolonged average escape latency during their training vs. WT counterparts (Table 1). Although there was no difference between performance in the MWM probe trial, LRA showed a negative association between LVPWd and the mean distance from the platform in the probe trial in 2xTg‐AD mice, and a positive association of LVPWd with number of entries to the platform zone (Table 2). There was a positive association between aPWV and mean distance from the platform in the probe trial in both 2xTg‐AD and WT mice.ConclusionsLRA results indicate that LV remodeling is associated with anxiety‐like behavior in 2xTg‐AD mice, but not with spatial memory impairment. Positive association of aPWV with spatial memory impairment in both groups suggests that aortic stiffness contributes to the age‐associated CI.Supported by the NIH/NIA IRP.

Role of path information in visual perception of joint stiffness.

Humans have an astonishing ability to extract hidden information from the movement of others. In previous work, subjects observed the motion of a simulated stick-figure, two-link planar arm and estimated its stiffness. Fundamentally, stiffness is the relation between force and displacement. Given that subjects were unable to physically interact with the simulated arm, they were forced to make their estimates solely based on observed kinematic information. Remarkably, subjects were able to correctly correlate their stiffness estimates with changes in the simulated stiffness, despite the lack of force information. We hypothesized that subjects were only able to do this because the controller used to produce the simulated arm's movement, composed of oscillatory motions driving mechanical impedances, resembled the controller humans use to produce their own movement. However, it is still unknown what motion features subjects used to estimate stiffness. Human motion exhibits systematic velocity-curvature patterns, and it has previously been shown that these patterns play an important role in perceiving and interpreting motion. Thus, we hypothesized that manipulating the velocity profile should affect subjects' ability to estimate stiffness. To test this, we changed the velocity profile of the simulated two-link planar arm while keeping the simulated joint paths the same. Even with manipulated velocity signals, subjects were still able to estimate changes in simulated joint stiffness. However, when subjects were shown the same simulated path with different velocity profiles, they perceived motions that followed a veridical velocity profile to be less stiff than that of a non-veridical profile. These results suggest that path information (displacement) predominates over temporal information (velocity) when humans use visual observation to estimate stiffness.

Review of Vibration Assessment Methods for Steel-Timber Composite Floors

Human comfort is recognized as an essential serviceability requirement for timber floors. Although several standards and design criteria are available for designing steel and concrete floors, there is no consensus among researchers on the applicability of such design methods to timber composite floors. Adding steel to timber floors is intended to create long spans, however, vibration is still a major challenge in achieving longer spans. To highlight the extent of this issue, a comprehensive search in the literature was conducted. The most common vibration criteria that may be used to assess the performance of steel-timber composite floors under human-induced vibrations were reviewed. For lightweight composite floors, the 1 kN deflection limit was found to be the most suitable vibration limit based on a wide range of subjective evaluation studies. For composite floors comprising steel and heavier timber subfloors, the relevance of 1 kN deflection criterion and other criteria suggested in the literature are questionable due to the lack of subjective evaluation studies. In the advent of advanced computing and data analysis, conducting detailed numerical analysis validated by accurate on-site measurements is recommended. Special attentions should be given to accurate estimation of connection stiffness and damping ratio according to the findings of this study.