Effect Of Low-frequency Vibration Research Articles

Effects of vehicle vibration on driver alertness: a pilot study

Road accidents resulting from the loss of driving alertness cause significant social and economic damage. In recent years, studies have revealed that whole-body vibration affects driver drowsiness directly. However, the impact of different frequency ranges of vibration on driver alertness has not been extensively explored. This driving simulator study aimed to investigate the impact of low frequency (1-4 Hz) and high frequency (16-32 Hz) whole-body vibration on a driver's reaction time during a monotonous highway driving task. Nine participants completed the task for one hour, with reaction tasks presented every 8-12 seconds. After 25 minutes of exposure to whole-body vibration, participants exhibited significantly longer reaction times for both low and high frequency ranges when compared to the control condition. The low frequency range had a stronger effect on driver vigilance, with reaction times increasing by as much as 135 ms within 35 minutes. Subjective evaluations using the Karolinska Sleepiness Scale (KSS) were consistent with the reaction time results. Overall, this study confirms that both low and high frequency vibration can reduce driver alertness, with the effect of low frequency vibration being more pronounced. Further research is suggested with larger sample sizes and wider frequency ranges.

Experimental investigation to evaluate the effect of low frequency vibration on performance of vibration assisted electrical discharge drilling of titanium alloy

Experimental investigation to evaluate the effect of low frequency vibration on performance of vibration assisted electrical discharge drilling of titanium alloy

The influence of low-frequency vibration on the restoration of the range of knee motion in laboratory animals after immobilization (experimental study)

Background. The term “joint contractures” is used to describe the loss of passive range of motion of diarthrosis joints, the most common and mobile type of a joint. Measuring passive or active range of motion in a joint with contracture is key to assessing the severity of joint contractures. The purpose of the study: to determine the impact of immobilization on the development of movement limitation in the knee joint of laboratory animals (rats) and to evaluate the possibility of restoring mobility in case of using low-frequency vibration during and after immobilization. Materials and methods. The experimental study was conducted on 30 non-linear white male rats aged 6 months. Immobilization of the pelvic limb was performed at an angle of 140° in the knee joint. The animals were randomly divided into 3 groups: I — immobilization and free restraint after immobilization, II — immobilization and vibration development of the joint after immobilization, III — immobilization and vibration development of the joint during and after immobilization. Vibration development of the immobilized knee joint was performed daily in the mode of 20 Hz with an amplitude of 1.5 mm and a duration of 10 minutes. The range of motion and real contracture were determined as the difference between the measured range of motion and the range of motion before the start of the experiment for each animal individually. Results. It was found that a rapid increase in movement limitation occurs starting from the 2nd week of immobilization. A decrease in the range of motion in rats of the groups I and II under conditions of immobilization occurred the same way. After the end of immobilization, a slow increase in the range of motion was observed in the group I; in the group II, the growth was almost linear and after 4 weeks, the indicator was close to the norm. In the group III, the limitation of the range of motion after immobilization was significantly less; therefore, accordingly, recovery took place already 2 weeks after the removal of the immobilization bandage. Immobilization of the knee joint in rats of groups I and II caused a contracture of 60°, while in the group III, the restrictions did not exceed 25°. And, accordingly, the recovery in the groups with vibration development was rapid; in the group III, a full recovery was achieved, in the group II — a recovery of up to 5° of the residual contracture. In the group I, we observe a residual contracture of almost 35°, which is more than the formed immobilization contracture in the group III. Conclusions. Low-frequency vibration allows reducing the impact of immobilization and significantly accelerate the recovery of mobi-lity (range of motion) of the joint after its completion. If it is impossible to carry out vibrotherapy during the period of immobilization, it should be started as early as possible after immobilization. To date, there are few studies considering the effect of low-frequency vibration on the development of immobilization contractures and their treatment. The obtained data require further research with longer periods of immobilization and those examining immobilization options and modes of vibration impact on the joints.

The Effects of Low-frequency Vibration on Aligner Treatment Duration: A Clinical Trial.

ABSTRACTObjectives:The aim of this study was to investigate the effectiveness of an orthodontic tooth movement acceleration device (AcceleDent, OrthoAccel Technologies, Houston, Texas) when used during an aligner treatment.Materials and Methods:Adult patients who began an aligner treatment (Lineo, Micerium Lab, Avegno, Italy) were allocated to two treatment groups. The first one (Group A), with a 7-day aligner change regimen, used the AcceleDent device for 20 min per day, whereas the second one (Group B) changed the aligners every 14 days and did not use any device. The registered outcomes were the possibility of completing the treatment, the number of aligners needed and treatment duration in the two groups. Moreover, we assessed patients’ perception of pain during the first week of treatment.Results:Twenty-four patients were allocated to Group A or B depending on the acceptance of AcceleDent use. Patients which used AcceleDent (Group A) completed the treatment using each aligner for fewer days than those belonging to Group B (9.0 ± 1.0 and 15.4 ± 1.2 days, respectively) (P < 0.001). As a secondary outcome, a significant difference was found in pain perception during the first week of treatment between the two groups (P < 0.05).Conclusions:This controlled clinical trial shows that is possible to apply a 7-day change regimen together with AcceleDent use and successfully complete an aligner treatment with a significant saving of time when compared to a standard 14-days change regimen. Finally, the use of this device allowed reduction in pain perception during the orthodontic treatment.

Tactile Low Frequency Vibration in Dementia Management: A Scoping Review.

The prevalence of dementia is increasing with the ever-growing population of older adults. Non-pharmacological, music-based interventions, including sensory stimulation, were reported by the Lancet Commission in 2020 to be the first-choice approach for managing the behavioural and psychological symptoms of dementia. Low frequency sinusoidal vibration interventions, related to music interventions through their core characteristics, may offer relief for these symptoms. Despite increasing attention on the effectiveness of auditory music interventions and music therapy for managing dementia, this has not included low frequency vibration. This scoping review, following the JBI methodology guidelines, was conducted to investigate participants’ responses to both sound and mechanical vibration, the characteristics of the delivered interventions, methodological challenges, and the specifics of the research experiments reported. An extensive search was conducted in BMC, CINAHL, Cochrane Central Register of Controlled Trials, EMBASE, ERIC, MEDLINE (OvidSP), Pedro, ProQuest Central, PsycINFO, Scopus, and Web of Science. Current Controlled Trials, Clinical Trials, and Google Scholar were also searched as well as a hand search in relevant journals. Studies on adults with all types of dementia, investigating tactile low frequency sound or mechanical vibration in any context were considered. Data from eight full-length studies (three RCTs, two quasi-experimental, two case reports, and one qualitative) were extracted using the data extraction table developed by the authors and were included in the analysis and critical appraisal. Issues in quality related to, for example, control groups and blinding. Few studies addressed participants’ subjective responses to the interventions. Reporting on the intervention characteristics was unclear. It appeared more frequent sessions led to better outcomes and home-based interventions potentially addressing the issue of access and feasibility. Future research should include neuroimaging to measure and confirm the hypothesised mechanism of cerebral coherence. Standardised reporting of intervention characteristics is also needed to ensure replicability of the experiments. Higher quality research is needed to investigate the impact and effect of low frequency vibration for the symptoms of dementia and compare outcomes in meta-syntheses.

The Effect of Low Frequency Sound on Heart Rate Variability and Subjective Perception: A Randomized Crossover Study.

Background: Vibroacoustic therapy (VAT) uses low-frequency sound, often combined with listening to music, for therapeutic purposes. However, the impact of low-frequency vibration (LFV) on physiological functions and subjective perception is relatively unknown. Methods: We conducted a randomized cross-over study with the aim of comparing the effect of constant LFV of 40 Hz, its amplitude modulation, and the placebo condition on heart rate variability (HRV), stress perception (measured by visual analogue scales for stress) and mood (measured by UWIST Mood Adjective Check List). Results: Research experiments with various interventions (constant LFV with sound of nature (river in forest), amplitude modulation of the same LFV with sounds of nature and sounds of nature without LFV) were realised involving 24 participants. It was found there was an effect on HRV, stress perception and mood after the interventions. However, there were only seldomly experienced, and mostly nonsignificant, differences between the intervention conditions, so the effects may be attributed to factors other than LFV. Conclusions: Large scale experimental studies are needed to verify the preliminary findings and to explore various coinciding factors that may have influenced the results of this study, e.g., type of autonomic nervous system. We propose that the effect of LFV exposure may differ when combined with listening to music, and this hypothesis should be investigated in future studies.

Study of the Surfactant Transport Law Based on an Improved Adsorption Model with an Artificial Seismic Wave

To explore the law and mechanism of enhanced surfactant flooding with a low-frequency artificial seismic wave, for single-phase fluids in porous media, a heterogeneous two-stage adsorption model for a surfactant with a low-frequency artificial seismic wave is introduced into the surfactant transport equation of a single-phase fluid. With this model, the surfactant fluid transport model in porous media with an artificial seismic wave is obtained. The model is solved using the C-N difference and chasing method. The migration law of the surfactant is simulated and quantitatively analyzed for different vibration accelerations, injection slug sizes, displacement speeds, and reservoir parameters with the action of low-frequency artificial seismic waves. The results show that artificial seismic waves can increase the effective range of the surfactants and reduce the number of chemical agents through reduced adsorption. Low-frequency vibration with the same surfactant injection rate can increase the effective range by a factor greater than one. For the same effective action distance, the dose of chemical agents can be reduced by more than 60%, and the optimal acceleration and the injection slug size are 0.3 m/s2 and 0.4 PV, respectively. With the increase of the injection rate, the effect of low-frequency vibration on the diffusion and transport of the surfactant decreases. A low-frequency wave combined surfactant has a better effect on the low permeability reservoirs. The research results provide important support for further understanding of the low-frequency artificial seismic wave composite surfactant flooding law and the optimization of the field parameters.

Mechanical behavior and material property of low-carbon steel undergoing low-frequency vibration-assisted upsetting

The propagation of ultrasonic wave in solids can cause a softening effect during metal deformation, and this concept has been widely exploited in micro-forming. Low-frequency vibration with micro-amplitudes was recently found to have a similar effect on metal deformation. In this study, the effects of low-frequency vibration on the mechanical behavior and microstructure of low-carbon steel DC04 during upsetting deformation was investigated. Vibration-assisted compression test results showed low-frequency vibration had a softening effect, that was proportional to vibration amplitude. Residual softening occurred in all cases during re-yield period after vibration removal. A sectional view of the deformed sample showed that vibration with larger amplitude could exacerbate the deformation of the contact area between the sample and the mold. The internal misorientation of grains in the deformation zone of the compressed sample increased significantly after large vibration treatment, indicating that low-frequency vibration promoted the occurrence of plastic deformation. A softening model considering transfer efficiency was proposed to explain the different performances under the action of small amplitude and large amplitude vibration. The residual softening effect that occurred in this study was an illusion produced by the uneven sample deformation caused by low-frequency vibration.

Influence of low-frequency vibration in Die Sinking EDM: a review

Electric discharge machining (EDM) is a thermal-based machining process where material removal in the form of melting and vaporization occurs due to repeated electrical sparks between electrode and workpiece. EDM process finds wide applications in the manufacturing, automobile, aerospace, and biomedical industries due to its remarkable feature of producing complex geometrical shapes like molds, tools, and dies. Irrespective of materials hardness. In this review, the paper author has given details about a new advancement made in the EDM process, which is low-frequency vibration-assisted Die Sinking EDM. There is also a brief introduction of vibration setups that can be used to generate low-frequency vibration. There is also some discussion about various optimization techniques (e.g., TOPSIS, MOORA, GRA) used to optimize the process parameters that are current, frequency, pulse on time, and pulse off time to get better response parameters ( MRR, TWR, and SR). Besides, there is extensive discussion about the effect of current, pulse on time, pulse off time and frequency on MRR, SR, and TWR. In the end, some discussion on the effect of low-frequency vibration on surface topography is also discussed.

English

English

Comparative study of low-frequency vibrations assigned to a workpiece in EDM and PMEDM

This study deals about the influence of vibrations incorporated into a workpiece during powder-mixed electrical discharge machining (PMEDM) on quality measures such as material removal rate (MRR), surface roughness [Formula: see text] and microhardness. It has been found that the low-frequency vibration incorporated into the workpiece positively affects the processing efficiency of electrical discharge machining (EDM) and PMEDM. However, the effect of low-frequency vibration in PMEDM has been better than EDM. The higher vibration frequency significantly improves the MRR and [Formula: see text] in PMEDM. The MRR has been improved by 95.89% and with lower [Formula: see text] of 63.2% in PMEDM. The hardness of the machined surface after PMEDM using titanium powder mixed in dielectric liquid was increased approximately two times as compared with conventional EDM.

Optimizing process parameters in edm using low frequency vibration for material removal rate and surface roughness

Vibration attached to workpiece in EDM (Electrical Discharge Machining) makes material removal rate (MRR) and surface roughness (SR) to be improved significantly. However, research results in this field are not so much. In this work, authors studied effect of low frequency vibration attached to workpiece SKD61 to efficiency in EDM. The effect of process parameters including pulse current (I), pulse-on time (Ton), pulse-off time (Toff) and vibration frequency (F) on MRR and surface roughness was investigated. The optimized parameter in EDM process using TOPSIS based multi objectives problem were performed. The experimental results have shown that the process performance accuracy has been enhanced to 86.6% through the Ci in low frequecy vibration assisted EDM process. This surface morphology of the machined specimen could also be improved under optimal process parameters.

Study on Effects of Low Frequency Vibration on Efficiency of Die Sinking Electrical Discharge Machining

The vibration integrated into die-sinking electrical discharge machining is a relatively new solution, so it has been creating the interest of researchers. In this paper, the authors studied the effect of low frequency vibration attached onto workpiece to efficiency of die- sinking electrical discharge machining. Copper electrode and SKD61 die steel were selected to investigate. Material removal rate, tool wear rate and surface roughness were quality indicators investigated in this study. Experimental results showed that the low frequency vibration has a positive effect on the efficiency of die-sinking electrical discharge machining. Comparing to die- sinking electrical discharge machining traditional, when the vibration unit is integrated onto work-piece in die-sinking electrical discharge machining, the largest increase of material removal rate was 34.94 %, the greatest reduction of tool wear rate was 16.0 % and the largest reduction of surface roughness was 26.36 % and profile of machined surface was better.

Beneficial Effects of Low Frequency Vibration on Human Chondrocytes in Vitro.

In articular cartilage, chondrocytes are the predominant cell type. A long-term stay in space can lead to bone loss and cartilage breakdown. Due to the poor regenerative capacity of cartilage, this may impair the crewmembers' mobility and influence mission activities. Beside microgravity other factors such as cosmic radiation and vibration might be important for cartilage degeneration. Vibration at different frequencies showed various effects on cartilage in vivo, but knowledge about its impact on chondrocytes in vitro is sparse. Human chondrocytes were exposed to a vibration device, simulating the vibration profile occurring during parabolic flights, for 24 h (VIB) and compared to static controls. Phase-contrast microscopy, immunofluorescence, F-actin and TUNEL staining as well as quantitative real-time PCR were performed to examine effects on morphology, cell viability and shape as well as gene expression. The results were compared to earlier studies using semantic analyses. No morphological changes or cytoskeletal alterations were observed in VIB and no apoptotic cells were found. A reorganization and increase in fibronectin were detected in VIB samples by immunofluorescence technique. PXN, VCL, ANXA1, ANXA2, BAX, and BCL2 revealed differential regulations. Long-term VIB did not damage human chondrocytes in vitro. The reduction of ANXA2, and up-regulation of ANXA1, PXN and VCL mRNAs suggest that long-term vibration might even positively influence cultured chondrocytes.

Effect of Low-Frequency Vibration on Muscle Response under Different Neurointact Conditions.

Stretch reflex is an important factor that influences the biomechanical response of the human body under whole-body vibration. However, there is a lack of quantitative evaluation at lower frequencies. Thus, the aim of this study was to investigate the effects of vibration on the stretch reflex and, in particular, to explore the quantitative relationship between dynamic muscle responses and low-frequency vibrations. The gastrocnemius muscle of 45 Sprague-Dawley rats was dissected. Sinusoidal vibrations of five discrete frequencies (2~16 Hz) with peak-to-peak amplitudes of 1 mm were applied to the gastrocnemius muscles with 2 mm or 3 mm prelengthening. Variables including dynamic muscle force, vibration acceleration, and displacement were recorded in two conditions, with and without the stretch reflex. Results showed that the dynamic muscle forces decreased by 20% on average for the 2 mm prelengthening group after the stretch reflex was blocked and by 24% for the 3 mm prelengthening group. Statistical analysis indicated that the amplitude of dynamic muscle force in the “with stretch reflex” condition was significantly larger than that in the “without stretch reflex” condition (p < 0.001). The tension-length curve was found to be a nonlinear hysteresis loop that changed with frequency. The phase difference between the dynamic muscle force and the length change was affected significantly by vibration frequency (p < 0.01), and the minimum frequency was 4–8 Hz. Experimental results of this study could benefit musculoskeletal model by providing a theoretical support to build a stretch reflex model for low-frequency vibration.

The Influence of Low-Frequency Vibrations on the Lipid Profile in Women

Introduction: The aim of this dissertation is an evaluation of the effect of low frequency vibration on serum lipid profiling women. Materials and Methods: A group of females aged 28-64 years old were assessed twice, before and after 19 days of exposure to low frequency vibration. The parameters of the vibration used (frequency and amplitude) and the short exposition time were selected in order to comply with standards established to safeguard human health; mechanical stimulus safe for human health according to the Polish Standard PN EN ISO 2631-1:1997. The parameters used were as follows: frequency 3.5Hz, amplitude 4 mm and duration time 20 min. The main exclusion criteria for this study were: neoplasm, history of myocardial infarction, history of stroke, history of bone fracture within the two years prior to the study. To assess the effect of low frequency vibration with the parameters as specified above the following physiological and biochemical variables were used: total cholesterol serum level, high density lipoprotein (HDL) cholesterol serum level, low density lipoprotein (LDL) cholesterol serum level, triglycerides (TGD) serum level. Biochemical blood parameters were assessed before and after the trial. Friedawald’s formula was used for the assessment of LDL cholesterol serum level. Upon completion of the study and the subsequent analysis of the results obtained the following conclusions were formulated. Results: A statistically significant lowering of total serum cholesterol and LDL serum cholesterol was observed. Conclusions: The use of the vibration platform with the operational parameters specified had a beneficial effect on the variables measured.

Accuracy and quality of micro-holes in vibration assisted micro-electro-discharge drilling of Inconel 718

Achieving micro-features on superalloy like Inconel 718, with dimensionally high accuracy, has never been easy using a conventional machining technique. Micro-electro-discharge drilling (µEDD) has emerged as one of the key machining technique for fabrication of micro-holes in such superalloys. Although the process has the proven potentials, quality and accuracy of micro-holes deteriorate due to high tool wear and process become unproductive due to the impasse of debris and unsteady machining conditions, especially for high aspect ratio hole drilling. To overcome such issues, anticipating a better performance, a low-frequency vibration assisted µEDD is proposed for machining of Inconel 718. Performance measures, such as material removal rate (MRR), electrode wear ratio (EWR), overcut, and taper angle are analyzed as results of the µEDD operation performed by choosing gap-voltage, capacitance, electrode rotation speed (ERS), and vibrational frequency (VF) as control factors. The Box–Behnken design was used to plan the experiments. The effect of low-frequency vibration on accuracy and surface quality of fabricated micro-holes was also discussed and compared with those achieved by without vibration assistance to the process. An enhancement in the performance of low-frequency vibration assisted µEDD due to improved flushing, debris evacuation, and stable machining conditions is noticed.

Effect of Low-Frequency Vibration on Human Body in Standing Position Exposed to Railway Vehicle

In this paper, the dynamic characteristics of the human body were investigated by developing a 3-D finite element model based on 50th percentile anthropometric data for a 54 kg Indian male subject in standing position by considering human body segments as an ellipsoid. The finite element modal analysis is carried out to extract several low-frequency vibration modes and its vibration mode shapes were presented in this paper. The results show that the lowest natural frequency of the standing passenger model occurs in the fore-and-aft direction. The second natural frequency occurs in the lateral direction and the first order natural frequency of the standing passenger model in the vertical direction occurs at 5.379 Hz. The model will be helpful to predict the vibration response of human body under various vibration environment encounters in the railway vehicle.

Effect of low frequency vibration on micro EDM drilling

A micro hole is a basic feature in micro manufacturing. Micro electrical discharge machining (EDM) is one of the key techniques for machining micro holes in metallic materials. Since debris is accumulated in the discharging gap between the tool electrode and the workpiece, it becomes increasingly very difficult to machine a micro hole as the chosen diameter is progressively decreased or the depth increased. The use of vibration in micro EDM drilling can improve machining efficiency by refreshing dielectric fluids and flushing out the debris from the gap. Although ultrasonic vibration over a few kHz has been introduced in many applications of micro EDM, it is difficult to apply to a workpiece of a very large size or mass. In this study, the effect of very-low-frequency vibration was investigated to improve the efficiency of micro EDM. Low-frequency vibration in the range of 10 to 70 Hz was applied to single-hole machining, to reverse EDM, and to multiple-hole machining. The machining efficiency was investigated while varying the vibration frequency and amplitude.

Low frequency and boundary condition effects on impedance based damage identification

Details of the investigations on the application of Electro Mechanical Impedance (EMI) technique using smart piezoelectric (PZT) sensors for damage detection of structures are presented in this paper. The behavior and the ability of this method to detect damages, in a homogenous material are studied for its effective utilization in structural health monitoring. Experimental investigations are conducted on a homogenous aluminium plate bonded with PZT patches to study the effects of external low frequency vibrations (mass loading) and boundary condition on EMI signatures and the observations are discussed using RMSD as damage index computed between pristine and damaged states. Effect of low frequency vibration on the resulting EMI signature and the corresponding RMSD is found to be less than 2%. This is the threshold upper control value (UCL) beyond which the change in RMSD shall truly reflect the damage.