Axial Deformation Research Articles

Characterization of thermal expansion in additively manufactured continuous carbon fibre reinforced polymer composites using fibre Bragg grating sensors

This study investigates thermal strains in fibre reinforced polymeric samples manufactured using a modified Fused Deposition Modelling (FDM) method. The investigated material was a composition of polylactic acid (PLA) resin and continuous carbon fibres. Each test sample was equipped with two Bragg grating (FBG) sensors, one embedded inside and the other bonded to the surface. Both sensors monitored temperature-induced deformations during the conditioning of the specimens in a thermal chamber. Multiscale, analytical and finite element method based models were implemented to quantify the temperature deformations.Research has revealed that in investigated samples, bending occurs due to thermal loading. This can result in an inaccurate estimation of the coefficient of thermal expansion when relying on surface deformation measurements. A proposed solution involves the use of one FBG sensor embedded inside the specimen or two FBG sensors placed symmetrically, capable of measuring axial thermal deformation and averaging the effects associated with bending.

Finite element analysis of the cervical spine: dynamic characteristics and material property sensitivity study

The study aimed to investigate the dynamic characteristics of the cervical spine and determine the effect of the material properties of the cervical spinal components on it. A finite element model of the head-cervical spine was developed based on CT scan data, and the first six orders of modes (e.g. flexion-extension, lateral bending, and vertical, etc.) were verified by experimental and simulation studies. The material sensitivity study was conducted by varying elasticity modulus of cervical hard tissues (cortical bone, cancellous bone, endplates, and posterior elements) and soft tissues (intervertebral disc and ligaments). The results showed that increasing the elastic modulus of ligaments by 4 times increased the natural frequency by 77%, while increasing that of cancellous bone by 4 times only increased the natural frequency by 6%. In the axial mode, the cervical spine had not only axial deformation but also anterior-posterior deformation, with the largest deformation located at the intervertebral disc C6-C7. Decreasing the elastic modulus of a component in soft tissues by 80% increased modal displacement by up to 62%. The material properties of the intervertebral discs and ligaments had opposite effects on the modal displacement and deformation of the cervical spine. Low cervical discs were more susceptible to injury in a vertical vibration environment. Cervical spine dynamics were more sensitive to soft tissue material properties than to hard tissue material properties. Disc degeneration could reduce the range of vibratory motion of the cervical spine, thereby reducing the ability of the cervical spine to cushion head impacts.

Effects of Loading and Compaction Conditions on Permanent Strains of Unbound Lateritic Soils from Senegal and Burkina Faso

Permanent strains of granular materials result from the repetitive passage of heavy trucks on the pavement. Pavement design relies mainly on permanent strains to predict rut depths. In order to contribute to the improvement of technical documents used for the design and modelling of pavements in tropical African countries, the researchers have focused on the determination of the permanent deformation parameters of laterites (axial (εp,1) and radial (εp,3) permanent strains). The Repeated Triaxial cyclic Loading (RTL) apparatus was used according to the European standard (EN 13286-7: 2004, Multistage method). Four sites of gravelly lateritic soils chosen, two from Burkina Faso (Badnogo2 and Dédougou) and two from Senegal (Sindia and Lam-Lam) were tested in this research. They are compacted to 95% and more of the optimum with a variation in water content of ±2% of the optimum. The permanents deformations are influenced by the water content, the compaction rate and the stress level. The axial permanent deformation ε1,p (max) decreases by 83.4% when the water content decreases from 12.10% to 7.59%. Moreover with a compactness rate that varies from 95.58% to 100.06%, respectively from a water content that varies from 10.04% to 9.36%, we observe a decrease in deformation ε_(1,p) from 224.340*10-4 to 148.150*10-4 from the 50,000 cycles, which shows the effect of the compactness rate and the stress level on the lateritic gravels materials soils. however, for a good control of permanent deformations on flexible pavements using gravel materials, it is necessary to compact at water contents lower than the optimum added to average compaction rates. Keywords: permanent strains (p), lateritic soils, Repeated Triaxial cyclic Loading (RTL), Sindia, Badnogo2, Dedougou, Lam-lam.

Research on the inflation process of underwater parachute by numerical simulation and model test

In order to meet the application requirements of the underwater parachute, the underwater inflation performance of a drag parachute is investigated based on numerical simulation and water tank test. A method for simulating the inflation process of underwater parachute based on Arbitrary Lagrangian Eulerian (ALE) method is proposed. The variation of axial force in the numerical simulation exhibits a similar trend to that observed in the model test, and the discrepancy of value between them is relatively insignificant. The purpose of this paper is to provide a basis for the evaluation and design of underwater parachutes for underwater applications. The effects of parameters such as permeability and flow velocity on the inflation performance are discussed in detail, and the analysis is carried out for parameters such as axial force and structural deformation. The results show that the high-stress zone and high-pressure intensity zone of the underwater parachute were found to be mainly concentrated in the center of the canopy and the joint. It can be observed both in model test and numerical simulation that, during the inflation process, vortexes are generated inside and outside the canopy. After the inflation shape of the canopy has stabilized under steady flow, lateral forces are generated on the parachute due to asymmetric vortex shedding, which cause the parachute to rotate around the axis.

Rotation and Asymmetry of the Axial Plane Pelvis in Cerebral Palsy: A CT-Based Study.

Spinopelvic malignment is commonly seen with non-ambulatory cerebral palsy (CP). Axial plane deformation is not well described in the literature. The purpose of this study was to describe and quantify the axial plane deformity in CP using CT scans and compare it to normal controls. We retrospectively collected data using CT scans of the abdomen and pelvis of 40 patients with GMFCS IV/V CP and neuromuscular scoliosis (CPP) and normal controls (NP) matched by age and sex. Pre-operative Cobb angle was recorded for the CP patients. Pelvic anatomy was evaluated at the supra-acetabular region of bone using two angles-iliac wing angle and sacral ala angle, measured for each hemipelvis. The larger of each hemipelvis angle was considered externally rotated while the smaller angle was considered internally rotated, termed as follows-iliac wing external (IWE) and internal (IWI); sacral ala external (SAE), and internal (SAI). Differences were noted using an independent t-test while correlations with Cobb angle were performed using Pearson's correlation. Iliac wing measurements showed the externally rotated hemipelvis showed a significantly greater magnitude compared with normal controls at 47.3 ± 18.1 degrees vs. 26.4 ± 3.7 degrees in NP (p < 0.001) while no internal rotation was observed (p > 0.05). Sacral ala measurements showed greater magnitude in both external and internal rotation. SAE was 119.5 ± 9.5 degrees in CPP vs. 111.2 ± 7.7 degrees in NP (p < 0.001) while SAI was 114.1 ± 8.5 degrees in CPP vs. 107.9 ± 7.5 degrees in NP (p = 0.001). In the CP cohort, the mean Cobb angle was 61.54 degrees (n = 37/40). Cobb angle correlated with the degree of external iliac wing rotation-IWE (r = 0.457, p = 0.004) and degree of absolute difference in the rotation of the iliac wing (r = 0.506, p = 0.001). The pelvis in a patient with CP scoliosis is asymmetrically oriented exhibiting a greater external rotation of one hemipelvis relative to normal controls. The severity of neuromuscular scoliosis is related to the pelvic axial rotation in CP patients. Axial plane deformity exists in the CP pelvis and this deformity warrants consideration when considering spinopelvic instrumentation strategies and outcomes of supra-pelvic and infra-pelvic pathologies.

Study on the Damage Characteristics and Internal Variable Modeling of Single-Fracture Sandstone under the Coupling Effect of Freeze–Thaw and Fatigue Load

The fractured rock mass in the western cold region is affected by freezing and thawing disasters and is prone to local damage and fracture along the fissures’ ends. The fatigue damage induced by repeated frost heave and traffic loads seriously endangers the stability of cold region roadbed. This paper selects sandstone as the research object. Firstly, 20 freeze–thaw cycles were performed on fractured sandstone samples with different inclination angles of 30°, 45°, 60°, and 90°. Subsequently, triaxial compression and triaxial fatigue loading tests were conducted to explore the mechanical properties and fracture morphology evolution mechanism during the compression process of freeze–thaw fractured sandstone. Nuclear magnetic resonance technology (NMR) was used to measure the H-containing fluid inside rock pores. The microscopic damage characteristics inside the rock were analyzed from the NMR T2 relaxation spectrum signal and pore size distribution characteristics. Based on the internal variable theory of continuum mechanics, a fatigue model of freeze–thaw fractured sandstone with different inclination angles was established. The results show that sandstone strength was negatively correlated with the fracture dip angle, and the axial deformation and shear failure angle were positively correlated with the fracture dip angle. The mechanical properties of the sandstone were deteriorated by fatigue loading. When the crack angle was 90°, the fatigue failure strength of the rock sample was the lowest. The T2 spectrum distribution of the fractured sandstone mainly had three peaks and the pore size was mainly medium and small pores. There was a small leftward shift after freeze–thaw cycles and fatigue loading. The T2 spectrum area was significantly affected by fatigue loading, with the highest rate of change at a crack angle of 30°. Through the fine correspondence between the axial residual deformation and the deformation modulus, a fatigue model with different crack inclination angles was established using the axial residual deformation as the internal variable, and the rationality of the model was verified by fatigue loading tests.

Improvement of axial deformation prediction in high-rise buildings with field monitoring and adaptive unscented Kalman filter

The deformation of vertical reinforced concrete members in high-rise buildings during their construction is constantly changing due to the complexity of the deformation mechanism, as well as the uncertainties that arise during the construction process; in some cases, accurate estimation of the vertical displacement is crucial. Based on on-site strain monitoring data and an adaptive unscented Kalman filter, this paper establishes a state equation for the axial deformation process. The elastic, inelastic and temperature deformation of concrete during the entire construction process are reasonably considered. Deformation is predicted using both the traditional Kalman filter and unscented Kalman filter, both of which achieved satisfactory results. But the unscented Kalman filter can improve the prediction accuracy and robustness by utilizing unscented transformations. Anomaly detection is integrated into every inference step to detect abrupt changes in external conditions and dynamically adjust calculation parameters, thereby reducing the dependency of the prediction results on input parameters.

LOW-CYCLE FATIGUE OF STRUCTURES WITH STRESS CONCENTRATORS

The results of experimental and theoretical studies of structures with stress concentrators under cyclic loads are presented. The studies were carried out on cylindrical samples with a V-shaped annular recess under mild cyclic loading. The tests were carried out on samples of the BrH08-Sh alloy with a cyclic change in the tensile load from 0 to 10.8 kN. Under such loading, the material in the recess area undergoes cyclic elastoplastic deformation, which leads to destruction as a result of low-cycle fatigue. For mathematical modeling of the elastic-plastic behavior and destruction of structures with stress concentrators, a variant of the theory of plasticity based on the theory of flow under combined hardening is used. In the chosen plasticity model, a memory surface is introduced that separates the processes of monotonous and cyclic loading. This separation makes it possible to take into account various features of isotropic and anisotropic hardening of the material. Anisotropic hardening is represented as a sum of microstresses of three different types, which make it possible to describe the effects of landing and stepping of the elastic-plastic hysteresis loop. The plasticity model makes it possible to assess the damaged state of a material based on the kinetic equation of damage accumulation based on the energy principle (the operation of microstresses in the field of plastic deformations). The material behavior model is embedded in the finite element software package SIMULIA Abaqus. The results of calculations and experiments on the magnitude of axial deformation, the average axial deformation on the surface of the recess and the number of cycles to failure are compared. It is found that in a design with a recess with a radius of 1 mm, a soft asymmetric loading with a unilateral accumulation of deformation (ratcheting) is realized in the concentration zone.

Coronal malalignment and axial spinal deformity might be related to increased fatigue in patients with adult spinal deformity

Coronal malalignment and axial spinal deformity might be related to increased fatigue in patients with adult spinal deformity

EFFICACY OF AYURVEDIC MANAGEMENT IN ASTHIMAJJAGATA VATA W.S.R. TO ANKYLOSING SPONDYLITIS – A CASE STUDY

In recent decades, lifestyle has had a significant impact on an individual's physical and mental health. Ankylosing spondylitis (AS) is a disease that poses serious challenges to the healthcare system. The human approach to life has created inconsistencies in our biological systems. Busy work, social life, bad posture at the office, physical activity and cramps while traveling - all these factors play a role in putting too much pressure on the spinal cord, causing back pain. how. It belongs to a group of rheumatic diseases known as spondyloarthropathy (SpA) and is a chronic inflammatory disease of the axial spine. This shows a strong correlation with the genetic marker HLA B27. Inflammatory back pain and progressive spinal stiffness are noticeable in the early stages of the disease, while chronic aggressive disease can cause severe axial immobility and deformity. In Ayurveda, the term Astimajagata Vata is used to refer to A.S. The concept of Ama with an imbalance of the Vata, Pitta and Kapha doshas is associated with the signs of inflammation and stiffness seen in ankylosing spondylitis. In modern medicine, there is no satisfactory treatment for this disease. Various Panchkarma procedures and Ayurvedic medicines have been found beneficial for these symptoms. We present a case of ankylosing spondylitis where the patient was considered to be suffering from asthma (asstimajagata vata) and was treated for 4 months using a combination of Panchkarma practices and Ayurvedic treatments. Assessment criteria were based on calculation of the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI). A total of two assessments were performed before and after 4 months of treatment. The patient showed good improvement with BASDAI. Improvements were also found in signs and symptoms of A.S.

Inelastic Deformation and Local Slenderness Requirements for Rectangular HSS Braces

Rectangular hollow structural sections (HSS) are commonly used as bracing in concentrically braced frames (CBFs) designed and detailed for seismic design requirements. As the primary yielding component in CBFs, braces are expected to sustain large inelastic axial deformation during earthquake loading. It is well known that their deformation capacity depends on the width-to-thickness ratio (local slenderness). Until 2013, HSS sections were produced to meet ASTM standard A500/A500M; after 2013, the ASTM 1085 specification was implemented, and since that time, HSS sections have also been produced to meet ASTM A1085/A1085M standards. Where the ASTM A500/A500M specification requires minimum yield and tensile stress values as well as a minimum elongation and tolerances on the wall thickness, the ASTM A1085/A1085M specification also requires a minimum Charpy V-notch (CVN) toughness, a maximum yield stress of the steel, and tighter tolerances on the wall thickness and radius of curvature of the corner. These requirements offer a more reliable brace for CBFs in seismic regions. Yet there has been limited research investigating the cyclic axial response of these members. A research study was undertaken to investigate the response of ASTM A1085/A1085M tubes using the response of ASTM A500C tubes as their reference. Forty-one brace specimens were tested under cyclic inelastic axial deformation. Comparison of the data shows that most of the ASTM A500/A500 M Grade C and ASTM A1085/1085M braces meet the respective requirements of their respective ASTM standard and that the differences between the performance of ASTM A500/A500M and ASTM A1085/1085M braces are not dramatic. In addition, the study investigated the impact of width-to-thickness ratio, global slenderness, and displacement history on the response of the braces. The data show that the current AISC 341-22 high-ductility slenderness limit for special concentrically braced frame (SCBF) braces is slightly conservative. However, the data suggest that the moderate ductility slenderness limit used for ordinary concentrically braced frame (OCBF) braces is significantly more conservative than required for consistent seismic safety. Further research is required to determine appropriate limits; this paper provides some initial recommendations based on this dataset.

Investigation of the edge effect in composites using the ANSYS software in a two-dimensional formulation

The possibility of using the universal software ANSYS to study the concentration of interlaminar stresses near the free edges of laminated composites in a two-dimensional finite element formulation is considered. In this case, the cross-section of a rectangular four-layer composite plate of finite width with free side edges subject to uniform axial deformation is simulated. To create it, an original technique is proposed which consists in using thermal stress. The presented calculation results are in good agreement with the results of other authors.

Experimental, numerical and analytical analysis of a single-span steel portal frame exposed to fire

The thermo-mechanical behaviour of single-span steel portal frames in fire conditions illustrates a sequential transition from an ambient temperature state through to eventual collapse, encompassing axial forces, moments and deformations. To investigate the thermo-mechanical behaviour, a fire test on an 8 m × 6 m steel portal frame assembly is conducted. Detailed thermal and structural responses of the frame are measured and presented. The experimental results reveal that the frame collapses post 31-min heating with a peak temperature approximating 800 °C. A typical inward collapse mode is observed. 2D and 3D finite element models are established and validated against experimental results, respectively. The numerical model is divided into three heating regions to mimic the behaviour exhibited during the fire scenario. Furthermore, a thermo-mechanical theory is proposed to analyse the fire behaviour of a single-span steel portal frame. Based on the fire response of a restrained steel beam, the thermo-mechanical behaviour can be segmented into four stages: the ambient temperature stage, thermal expansion stage, elasto-plastic stage and catenary stage. A comprehensive series of calculation formulas determine the displacement, internal forces and moments at different stages. The analytical computations exhibit a close consistence with the numerical results, within the deviation of 10% for the majority. This analytical method can be effortlessly employed for both the fire-resistant design and assessment of the current state of steel portal frames in fire conditions.

The evolution of the compaction process and the deformed state of porous blanks during their hot forging in the open die

The article presents the results of the study of the evolution of the deformed state of the workpieces, the energetic parameters of the process and the distribution of porosity over the volume of the forging at all stages of hot forging of porous powder forgings in an open die. Modeling of the process was carried out using the finite element method using the DEFORM 2D/3D software complex. As a result of the simulation, it was found that at the initial stage of the process, the blank is mainly compacted with minimal radial flow of the material. Noticeable flow of metal into the groove groove area begins only when the forging material reaches an average relative density exceeding 90%. A significantly different nature of the distribution of axial er and radial ez deformations over the volume of the forging was noted. A zone with increased levels of values of axial deformations is formed in the central layer of the forging, equidistant from the upper and lower surfaces of the die cavity, and the values of radial deformations decrease with distance from the zone bordering the free side surface of the workpiece in the radial (to-center) direction. The minimum values of ez and er appear in the upper and lower angular stagnant zones of the forging. It is shown that the graph of the dependence of the deformation force on the displacement of the punch is marked by the presence of at least three characteristic sections due to the relationship between the processes of compaction and forging shape change at each stage of the process.

Research on the nonuniform contact characteristics and thermal behavior of friction pairs involving the radial conical buckling deformation in hydro-viscous drive

An equivalent model and a finite element method was established and used for simulating the change of contact state and pressure distribution of friction pairs under the axial pressure to obtain the radial nonuniform contact characteristics and temperature field of conical friction pairs during the soft-start condition. A two-dimensional temperature field calculation model was established based on the results of contact characteristics and convective heat transfer conditions, and the transient temperature field of friction pairs during soft-start was calculated by the finite difference method. Finally, the effects of the soft-start time, deformation degree, and thickness of the steel disk were studied. The results show that the temperature and contact pressure distribution of conical deformation friction pairs exhibit local high-temperature and high-pressure areas during the soft-start process. In the early stage of soft-start, the conical friction element locally contacts in its radial central area. The contact area spreads from the center to both sides as the soft start time increases, and two contact pressure peak areas are formed near the inner and outer diameters with the increase in axial pressure. The degree of axial deformation of conical steel disk has a significant impact on contact pressure. The larger the axial deformation, the pressure distribution would be more uneven. The distribution of temperature field is significantly affected by the contact pressure. It spreads from the middle to both sides, forming high-temperature regions in the pressure peak areas. Meanwhile, the temperature on the outer side of the friction element is higher than that of the inner side due to the influence of convective heat transfer. The duration of soft start also has a significant impact on the maximum temperature and maximum temperature difference. The results could provide a theoretical basis for exploring the correlation between the thermal buckling deformation and torque instability.

The effect of varying stress intervals on fatigue of rock salt

The surrounding rock of underground energy storage salt caverns is subjected to periodic loading with stress intervals during actual operation. To study the fatigue behavior of rock salt with such stress intervals, one conventional fatigue test and three fatigue tests with multi-step varying stress intervals (MVSIs) were conducted. The results show that the circumferential deformation first decreases and eventually becomes similar to the axial deformation in fatigue tests with MVSIs, as the interval duration increases. Both the dissipated energy and the spacing between the loading and unloading curves of a single cycle first decreased, then remained constant, and finally increased sharply as the stress interval increased. When the stress intervals corresponded to the elastic phase of loading (between 20% and 40% of the uniaxial compressive strength), the rock salt was subjected to the minimum damage. Based on the Bauschinger effect and dislocation internal friction theory, the micromechanism of rock salt fatigue was further explained.

Investigating the fire resistance of corrugated steel columns

This research paper focuses on investigating the fire resistance of axially restrained Corrugated Plate Steel columns (CRG) exposed to hydrocarbon fire conditions. Key parameters, including corrugation depth, plate thickness, axial load percentage, and column length, were analyzed to assess their impact on the fire resistance performance of CRG columns. A comprehensive analysis involving 80 finite element (FE) models was conducted using ABAQUS software. The analysis process encompassed studying temperature distribution within the columns, observing buckling modes, and determining the durations of buckling and failure fire resistance. The adopted FE model has been verified by comparing it to experimental data presented in the relevant literature. Findings reveal that corrugated CRG columns exhibit superior resistance to buckling and structural failure compared to circular cross-section columns. Corrugation depth minimally affects fire resistance but influences axial deformation and generated axial force due to increased structural stiffness. Increasing plate thickness improves fire resistance, particularly at lower axial load levels, while increasing axial load percentage decreases fire resistance. Doubling the column length has no significant effect on fire resistance, but columns with smaller plate thicknesses exhibit lower resistance under high axial load conditions. These insights inform the design and construction of CRG columns in structures exposed to hydrocarbon fire risks, aiding in enhancing fire safety and performance.

The synergy between texture evolution and grain refinement in a BCC steel

ABSTRACT This work investigates the synergy between texture evolution and grain refinement in ultra-low carbon body-centred cubic (BCC) ferritic steel. In this regard, experiments and polycrystal plasticity for ambient compressive deformation in low (up to ϵ≈0.22) and moderate (ϵ≈0.22−0.69) strain regimes were carried out. The tests were interrupted at intermediate strains for microstructure and texture characterisation. It was observed that the change in texture to γ -fibre ( { 111 } ∥ Compression direction ( CD ) ) and the formation of θ -fibre ( { 100 } ∥ CD ) up to ϵ ≈ 0.22 contributes towards lattice bending, resulting in grain size reduction from ∼ 104 ( 23 ) μ m to ∼ 23 ( 6 ) μ m . Simultaneously, crystallite size decreases, and statistically stored dislocations (SSD) and geometrically necessary boundaries (GNB) increase rapidly. Thus, resulting in an abrupt decrease in strain hardening rate (SHR). From ϵ ≈ 0.22 − 0.69 , the γ and θ -fibre broadens and θ -fibre intensity increases. The low GNB density increase indicates insignificant deformation-induced lattice curvature formation within grains, resulting in SSD intensification. Thus, leading to elongated grains with sluggish grain size decrease to ∼ 17 ( 4 ) μ m and a lesser decrease in SHR. The α -fibre could not evolve due to the dispersion of 110 axes along the axisymmetric radial direction due to axial deformation. The polycrystal model could appropriately simulate strain-hardening behaviour and texture evolution.

Axial compression performance of concrete-filled-steel tube flat columns with a large steel ratio

To prevent columns protruded from the inside wall, concrete-filled steel tube flat columns (CFSTFCs) with a large steel ratio were proposed in this study by limiting the sectional width and increasing the sectional height. The influence of the aspect ratio and thickness of the steel tube on the axial compression performance of CFSTFCs was investigated by axial compression tests for 12 CFSTFCs. The test results showed that two different failure modes, including a horizontal buckling ring with welding seam fracture and overall instability with local buckling in the sectional height direction, occurred in the tests. The axial load-carrying capacity and axial deformation ductility of CFSTFCs were enhanced with increasing thickness of the steel tube under the same aspect ratio. However, the axial deformation ductility of CFSTFCs gradually decreased with increasing aspect ratio. Furthermore, the Mander and Han Linhai confined concrete models were used to simulate the in-filled concrete in CFSTFCs to analyze the confinement effect from steel tube to in-filled concrete in CFSTFCs. Finally, the tested ultimate axial load-carrying capacity of CFSTFCs was compared with the different specifications to acquire the design method of CFSTFCs.

Morphological analysis of the human earcanal deformations during face-related activities

Ear-related technologies are spreading in our daily life and have become essential in several applications. The comfort, retention and battery life of in-ear devices can be substantially improved by considering the dynamic behavior of the earcanal. A better understanding of the earcanal dynamic motion would not only result in the improved fit and performance of earpieces but could also pave the way to harvest energy from these movements to power future ear-related technologies. The contours of the left and right ears of 18 healthy subjects during closed mouth and 4 activities (mouth opening, turning head left, raising eyebrows and smiling) were discretized. Eight parameters were analyzed to investigate the possible relation between each of these face-related activities and the radial and axial deformations of the earcanal. The largest significant deformations in reference to the closed-mouth geometry were observed during mouth-opening and smiling at the earcanal entrance and between the two bends.