Deformation Tests Research Articles

Prediction of multistage fatigue curve based on the relaxation model of irreversible cyclic deformation

The paper studies the multi-stage fatigue dependence (Wöhler diagram) of the material and proposes a new model for its prediction based on considering the mechanisms of plastic deformation and fracture under cyclic loads and a combination of relaxation processes with the evolutionary development of damage, for which the initial condition is formed using the calculation calculated during the cycling process energy of irreversible deformation. The performance of the model is verified using the results of cyclic deformation tests on DP500 steel as an example. It is shown that within the framework of a unified approach it is possible to simultaneously evaluate the short-term, fatigue and long-term strength of the material.

Effect of anchor shear deformation on the propagation rules of excitation stress waves

To address the shear deformation failure resulting from misalignment of rock strata in anchor support, a range of methods, including laboratory tests, numerical simulation, and others, are employed to study the deformation process of anchor rods under shear comprehensively. This approach permits an investigation of the deformation characteristics of the surrounding rock and anchoring agent under shear. Moreover, the propagation characteristics of the stress wave in the anchor rods under shear with varying degrees of deformation have been elucidated. A novel non-destructive testing method for assessing the degree of shear deformation in anchor rods is proposed based on the correlation between the energy evolution law of the stress wave and the degree of anchor deformation. Following experimental verification, it was determined that the average discrepancy between the detection outcomes of the stress wave method and the actual measurement results was minimal and consistent. The findings provide a theoretical foundation for the non-destructive testing of anchor rod shear deformation under on-site support conditions.

The synchronous measurement of mechanical and magnetic characteristics of superconducting materials in extreme environments

Thermomagnetic instability typically occurs before the quench of high temperature superconductors. Magnetic perturbation and thermal agitation are known to be the main driving force of thermomagnetic instability. However, the interaction between mechanical deformation and the thermomagnetic instability is still unclear. To investigate the phenomenon and inner principle of the thermomagnetic instability induced by mechanical deformation, an experimental method is proposed for the in-situ, real-time, and synchronous test of mechanical deformation and magnetic flux based on digital imaging correlation (DIC) and magneto-optical imaging (MOI). Under the current-carrying and external magnetic field conditions, uniaxial tensile tests of YBa2Cu3O7-δ (YBCO) coated conductors (CCs) are carried out, in which the evolution and distribution magnetic flux induced by strain are studied. At the same time, chemical etching is adopted to explore the damage caused by mechanical deformation in YBCO layer. It is found through the experiment that the mechanical deformation can induce thermomagnetic instability, and threshold of strain for inducing flux motions is obtained. Meanwhile, magnetic flux avalanche occurs in front end of the flux penetration area in the case of current carrying. In addition, plenty of various-sizes transverse cracks are discovered in the superconducting layer whose distribution area basically coincides with the flux penetration area. The experiment results reveal the intrinsic correlation between the mechanical deformation and thermomagnetic instability of high temperature superconducting wires, which provides a direct experimental approach for the study of unpredicted quench behaviors of superconducting magnets.

Advanced Mullins Damage Modeling (AMDM) after Multiple Cyclic Loading in Vulcanizates; Part 1: Theory and Parameter Identification

Abstract This study explores the deformation behavior of carbon black-filled elastomeric components under multiple cyclic loading conditions. Understanding the effects of repeated cyclic deformation is crucial for accurate Finite Element Method (FEM) simulations. We present an approach that captures both initial and subsequent cycles, converging to an equilibrium state. Experimental evidence from cyclic deformation and relaxation tests indicates that an equilibrium state is achieved within five deformation cycles. Our method analytically describes the relaxed or equilibrium state after multiple cyclic deformations by combining a relaxation model with a material model. We utilized a combination of a relaxation approach and the Modified Extended Tube Model (METM), allowing us to distinguish between polymer network effects and filler properties, thereby establishing a direct correlation between elastomer parameters and mechanical properties. The multiple cyclic deformation behavior can be analytically described using the Advanced Mullins Damage Modeling (AMDM) approach, validated through experimental data. The AMDM employs two damage functions for the increasing and decreasing stress phases of the cycle using the relaxed METM approach. The feasibility of this approach is demonstrated through 3D finite element (FE) simulations, confirming the validity of AMDM under cyclic deformation. The combination of the relaxed METM and AMDM approaches provides a robust framework for predicting the cyclic deformation behavior of filled elastomers, with significant applications in engineering and material science.

Mechanical Performance and Life Cycle Assessment of Soil Stabilization Solutions for Unpaved Roads from Northeast Brazil

This article presents the results of laboratory tests conducted to identify the granulometric stabilization and chemical improvement techniques used in an experimental segment of the unpaved BR-030 highway in the Maraú Peninsula, Bahia. The segment was designed to evaluate the performance of primary coating sections stabilized with sand, clayey gravel, reclaimed asphalt pavement (RAP), and simple graded crushed stone (GCS), as well as chemically improved with Portland cement and hydrated lime. The laboratory campaign focused on mechanical resistance, resilient modulus, and permanent deformation tests. In this research, chemical improvement with the addition of 2% Portland cement presented the most promising results for potential application in the section of the BR-030 highway intended to remain unpaved. Additionally, a life cycle assessment (LCA) revealed that mechanical stabilization of the primary coating has the lowest environmental impacts, making it a suitable and sustainable option among stabilization methods.

Regulation of Glass Transition Temperature in Thermo‐Responsive Epoxy Shape Memory Polymers: The Roles of Chemical Crosslinking Density and Chain Flexibility

ABSTRACTShape memory polymers (SMPs) are novel kinds of smart materials whose shape can be changed in external conditions such as heat stimulus. Due to their excellent structural versatility and high elastic strain, they have important applications in the field of biomaterials. Here, a series of amorphous shape memory polymer materials are prepared and their shape memory properties and glass transition temperature (Tg) are also investigated. A special kind of epoxy polymer, whose shape can be changed at around physiological temperature, is synthesized by regulating the crosslinking density and introducing flexible aliphatic epoxy chains. The shape memory function of this epoxy polymer is studied by deformation test. In addition, to explore their application in the field of biomedical materials, the biocompatibility of the materials are evaluated, including the effects on the erythrocyte hemolysis rate and cell activity. The experimental results show that this kind of epoxy polymer has good shape memory function and biocompatibility.

Research on hot deformation behavior and microstructure characterization of the NiTi alloy fabricated by wire arc additive manufacturing

This study investigates the hot deformation behavior and microstructural evolution of wire arc additive manufactured (WAAMed) NiTi alloy. Hot deformation tests were conducted within a temperature range of 750–900 °C and a strain rate range of 0.01–5 s−1, achieving a height reduction of up to 50%. The Strain-Compensated Arrhenius-Type (SCAT) model and deformation processing maps were developed. The microstructures of compression specimens at strain rates of 0.01 s−1 and temperatures of 750–900 °C were characterized. The results demonstrate that the flow stress of WAAMed NiTi alloys increases with increasing strain rate and decreases with increasing deformation temperature. The calculated values from the SCAT model align closely with the experimental values, indicating a reliable analysis with high prediction accuracy. Flow instability region expands as the degree of deformation increases, and the optimal processing windows for the studied alloy are concentrated within the range of 800–900 °C and 0.01–0.05 s−1. In the deformed WAAMed NiTi alloys, the proportion of low-angle grain boundaries is around 70% and the recrystallized grain fraction remains below 15%. This is attributed to the predominance of dynamic recovery behavior in the softening mechanism. Discontinuous dynamic recrystallization and continuous dynamic recrystallization as auxiliary softening mechanisms are also involved in the softening of NiTi alloys, leading to a steady state of flow behavior.

Mechanisms and characteristics of sand seepage deformation under groundwater level fluctuation scenarios

Seepage deformation in sand results from complex water-soil interactions, which are the primary reasons of sand surface collapse, as well as instability and deformation in dam foundations, building foundations, and slopes. Frequent fluctuations in groundwater levels cause changes in the direction, velocity, and pore water pressure of groundwater within the sand. Further research is essential to fully understand the characteristics and mechanisms of sand seepage deformation under varying groundwater conditions. In this study, natural undisturbed sand samples were collected. Laboratory seepage deformation tests were conducted to simulate continuous rises and falls in groundwater levels, exploring the response characteristics of internal erosion and hydraulic behavior of the sand under varying groundwater flow rates and directions. The results show that: As groundwater flow rate increases, the sand undergoes multiple episodes of seepage deformation, which includes the processes of structural stability, seepage deformation, and seepage failure. Initially, the hydraulic gradient for seepage deformation is small, and the particles carried by seepage are small. With a further increase in groundwater flow velocity, the hydraulic gradient rises, larger sand particles are migrated by seepage, and seepage failure may eventually occur. When the karst groundwater level is lower than the elevation of the sand bottom (H2 < z2) and the sand bottom is in a negative pressure state, the hydraulic gradient of seepage deformation is usually smaller than that observed in the other two states of positive pressure. In these cases, pore water pressure exerts an upward buoyant force, while in the negative pressure state, the pore water pressure transforms into downward suction. This downward suction aligns with the direction of gravitational forces and downward seepage force acting on the sand, making seepage deformation of the sand more likely. Sands with greater unevenness, finer particle, and lower density are more prone to seepage deformation but failure at different hydraulic gradients.

Strain hardening of acid-induced sodium caseinate gels as a function of pH and temperature

Strain hardening is a type of rheological behaviour that can be observed in large deformation tests of various materials. In oscillatory shear rheometry, it is characterised by an increase in storage and loss modulus (G′ and G″) with increasing oscillation amplitude (i.e, shear strain) until the material fractures and the moduli drop again. Acid-induced caseinate gels were previously shown to exhibit such a strain hardening behaviour. However, it has not been studied in much detailed how the extent of strain hardening is affected by pH and acidification temperature. In this work, the strain hardening of acid-induced caseinate gels was characterised as a function of pH by starting strain sweeps at various time points during acidification with glucono-delta-lactone, and the experiments were conducted at either 20, 30 or 40 °C to investigate the impact of temperature. The results demonstrate that the strain at fracture and the extent by which G′ increases with the strain amplitude change throughout acid-induced gelation of sodium caseinate in a complex manner with characteristic minima and maxima being barely related to the parameters observed in small strain experiments. The findings demonstrate the importance of considering the pH and temperature when characterising the strain hardening of caseinate gels as previous work showed that the strain hardening properties are related to water expression in forced syneresis experiments.

Research on orthotropic anisotropy characteristics of thick bedded limestone based on in situ deformation tests

The orthotropic anisotropy of sedimentary rocks has a significant impact on the force and deformation behavior of the project. In this paper, radial pressurization tests were carried out in the borehole in a typical northern karst area to obtain the deformation properties and orthotropic anisotropy of the rock masses. The test results showed that the deformation modulus and elastic modulus of the limestone rocks in the dam site area obeyed normal distribution. The deformation modulus was basically larger than the proposed deformation modulus of Class II rocks (10 GPa). The deformation behavior and anisotropy degree of the limestone showed a weak correlation with the elevation, but a strong correlation with the development density of the rock joints. The larger development density of the rock in the right bank test section leads to a larger degree of orthotropic anisotropy and frequency of occurrence.

Design and manufacturing of a dynamically deformable liver phantom for radiotherapy

Phantoms representing anatomical deformations are necessary to investigate and improve dynamic treatments. In this study, we aimed to produce a deformable liver phantom by simulating respiratory motion.The dynamically DEformable Liver Phantom (DELP) is designed to create a human-specific respiratory model and to produce synchronised, repeatable motion with this model. For the deformation effect of this movement, an artificial liver was created using silicone material and mold. A stepper motor was used to compress the liver in the inferior direction according to an adjustable respiratory motion. Reference markers (fiducial) placed on the DELP helped to verify the movement and calculate the deformation. In dynamic deformation tests, the greatest amount of deformation was found in the edge region of the silicone liver. The average deformation was 3.45 ± 0.93 mm when 5 mm amplitude movement was applied and 5.98 ± 0.01 mm when 10 mm amplitude movement was applied.DELP is a deformable liver phantom with motion reproducibility. Its performance in radiotherapy application was evaluated using dosimetric equipment.

Synergistic effect of B and Y on the corrosion of S31254 super austenitic stainless steel under stress

The corrosion behavior of S31254 microalloying with B and Y was investigated after experiencing the tensile and compressive deformation. After three-point bending deformation test, the local misorientation and plastic deformation caused by tensile deformation were larger than compressive deformation. The synergistic effect of B and Y reduced local residual stress of samples after both tensile deformation and compressive deformation. Electrochemical test showed that the synergistic effect of B and Y enhanced corrosion resistance more effectively than microalloying with B alone. In the immersion corrosion test, the tensile region showed higher stress corrosion sensitivity due to the higher plastic deformation than that in compressive region. The 50B+50Y sample exhibited better corrosion resistance than 50B sample and 0B sample in the tensile region with low plastic deformation. With the decrease of tensile deformation, the synergistic effect of B and Y on reducing the corrosion sensitivity was more obviously than B alone.

Surface matching design of carbon fiber composite honeycomb

Applying carbon fiber composite honeycomb in curved sandwich shells faces challenges due to the saddle-shaped bending surface in hexagon configurations and potential damage during the shape-forming process. This study analyzes the bending deformation of honeycombs by developing large deformation theoretical model for their bending surfaces. The study introduces two novel honeycomb configurations—Boomerang-shaped with a positive Poisson's ratio and Jellyfish-shaped with a negative Poisson's ratio—achieved through curved-wall design and fabrication using a modified carbon fiber composite tape winding molding process. Experimental tests, including bending deformation and shape-forming tests, measure the three-dimensional bending surfaces and mechanical responses of carbon fiber composite honeycombs. Additionally, a developed finite element model analyzes the damage states of various carbon fiber composite honeycombs during shape-forming processes. The results reveal the bending deformation of carbon fiber composite honeycombs and present damage state cloud maps to facilitate the optimal matching of objective sandwich shells with minimal scathe.

Analysis on dynamic characteristics of dam material and seismic response of embankment dam in Longyang Reservoir

PurposeThe geological conditions of Longyang Reservoir are complex and it is located in strong earthquake area. In order to determine its seismic characteristics, the seismic response and residual deformation of embankment dam should be studied to provide calculation basis for dam design and construction.Design/methodology/approachBased on the geological survey data of Longyang Reservoir, the dam filling materials are tested by dynamic deformation tests, and the equivalent linear constitutive model parameters of the filling materials are obtained. Based on Duncan-Chang E-B model, the stress state of embankment dam in Longyang Reservoir before earthquake is calculated, and the dynamic response and earthquake residual deformation of embankment dam in Longyang Reservoir under earthquake condition are calculated by using equivalent linear model and Shen Zhu-jiang’s residual deformation model.FindingsThe results show that with the increase of dynamic shear strain, the dynamic shear modulus decreases and the damping ratio increases. The scatter plot between dynamic shear modulus and dynamic shear strain, and the scatter plot between damping ratio and dynamic shear strain under different confining pressures show strips. The calculation results shows that the acceleration of embankment dam in Longyang Reservoir increases with the increase of dam height, and the acceleration distribution has obvious amplification effect. Combined with the maximum dynamic shear strain during the earthquake and the state before the earthquake, the maximum vertical residual deformation of embankment dam in Longyang Reservoir is 2.98 cm which occurs at the top of the dam, calculated by the Shen Zhu-jiang’s residual deformation model.Originality/value Finite element calculation model parameters of embankment dam are obtained by dynamic triaxial tests. Seismic dynamic responses and residual deformation of embankment dam are analyzed. With the increase of dam height, the acceleration distribution shows an obvious amplification effect. The vertical displacement of embankment dam is larger along the dam axis and decreases in the upstream and downstream direction. The maximum horizontal displacement of embankment dam occurs in the middle of upstream and downstream dam slopes.Highlights(1)Finite element calculation model parameters of embankment dam are obtained by dynamic triaxial tests.(2)Seismic dynamic responses and residual deformation of embankment dam are analyzed.(3)With the increase of dam height, the acceleration distribution shows an obvious amplification effect.(4)The vertical displacement of embankment dam is larger along the dam axis and decreases in the upstream and downstream direction.(5)The maximum horizontal displacement of embankment dam occurs in the middle of upstream and downstream dam slopes.

Оценка удароопасности массива горных пород Стрежанского месторождения

The article considers the aspects of assessment of the rock burst hazard of the rocks of the Strezhan deposit using various methods: visual inspection, fracturing of the massif, core disking, and lab tests for extreme deformation. In 2023, ore samples and host rocks were selected at the Strezhan deposit to determine their deformation and strength properties. The studies revealed their high strength. In the same year, the components of the stress tensor were measured at the mine using the well hydraulic fracturing method at two measuring stations at a horizon of +750 m (at a depth of approximately 240 m from the daytime surface). It has been established that the natural field of the Strezhan deposit is characterized by a tectonic regime with horizontal tectonic stresses as maximum stresses, whereas vertical stresses are minimal. The azimuth of the maximum horizontal stress was 140 ± 10° in the northwest-southeast direction. As a result of field measurements of the natural stress field at the horizon +750 m at the Strezhan deposit, the values of the highest horizontal stresses in the rock mass (ore) were established as equal to 15.2 MPa. This means that the level of stress of the rock mass at the horizon +750 m (mining horizon) is insufficient to destroy mine workings. Calculations established the critical depth of mining operations as 500 m for the rock burst condition. In addition, ores prone to rock bursts have been detected in the deposit: solid copper-zinc and sulfur-pyrite. The assessment of the structural disturbance of the deposit rocks via the rock quality index RQD = 60.26 % enabled the classification of the deposit rock mass mainly as moderately fractured, where dynamic manifestations of rock pressure are not registered and not forecasted within the designed mining depths. As a result of the studies, it has been established that the rock mass of the Strezhan deposit located at a depth of 500 m from the daytime surface can be classified as non-hazardous in terms of rock bursts on the condition of observation of the mining technology adopted in the design.

DETERMINATION THERMAL AND MECHANICAL PROPERTIES OF NANO CARBON, GRAPHITE AND GRAPHENE REINFORCED RECYCLING POLYPROPYLENE COMPOSITE SAMPLES

Polymer-based plastic materials occupy a major place in daily life. However, due to the nature of polymer materials, low thermal resistance and mechanical properties of these products, the need for new and sustainable materials in the industry has increased. With the rapid technological developments in advanced manufacturing industries such as aviation, marine, motor sports and defence industry, lightweight and high-strength composite products have become even more important. In this context, in this study, 1% carbon, graphene and graphite particle reinforced Polypropylene (PP) composite material mixed in a twin-screw extruder and MA/G series injection moulding machine standard tensile test sample produced. Melt Flow Index (MFI), Heat Deformation Test (HDT), tensile test, Shore-D hardness measurement and density tests performed on these test samples. According to the results obtained from these tests, the mechanical and thermal properties of the test samples produced from different composite materials were determined. The best mechanical and thermal properties occurred in the graphene particle. It formed in graphite and carbon, respectively.

Tissue expansion mitigates radiation-induced skin fibrosis in a porcine model

Tissue expansion (TE) is the primary method for breast reconstruction after mastectomy. In many cases, mastectomy patients undergo radiation treatment (XR). Radiation is known to induce skin fibrosis and is one of the main causes for complications during post-mastectomy breast reconstruction. TE, on the other hand, induces a pro-regenerative response that culminates in growth of new skin. However, the combined effect of XR and TE on skin mechanics is unknown. Here we used the porcine model of TE to study the effect of radiation on skin fibrosis through biaxial testing, histological analysis, and kinematic analysis of skin deformation over time. We found that XR leads to stiffening of skin compared to control based on a shift in the transition stretch (transition between a low stiffness and an exponential stress-strain region characteristic of collagenous tissue) and an increase in the high modulus (modulus computed with stress-stretch data past the transition point). The change in transition stretch can be explained by thicker, more aligned collagen fiber bundles measured in histology images. Skin subjected to both XR+TE showed similar microstructure to controls as well as similar biaxial response, suggesting that physiological remodeling of collagen induced by TE partially counteracts pro-fibrotic XR effects. Skin growth was indirectly assessed with a kinematic approach that quantified increase in permanent area changes without reduction in thickness, suggesting production of new tissue driven by TE even in the presence of radiation treatment. Future work will focus on the detailed biological mechanisms by which TE counteracts radiation induced fibrosis. Statement of significanceBreast cancer is the most prevalent in women and its treatment often results in total breast removal (mastectomy), followed by reconstruction using tissue expanders. Radiation, which is used in about a third of breast reconstruction cases, can lead to significant complications. The timing of radiation treatment remains controversial. Radiation is known to cause immediate skin damage and long-term fibrosis. Tissue expansion leads to a pro-regenerative response involving collagen remodeling. Here we show that tissue expansion immediately prior to radiation can reduce the level of radiation-induced fibrosis. Thus, we anticipate that this new evidence will open up new avenues of investigation into how the collagen remodeling and pro-regenerative effects of tissue expansion can be leverage to prevent radiation-induced fibrosis.

Mechanical Performance Assessment of a Hot-Mix Asphalt Modified with Biochar Obtained from Pine Wood Shavings

Diverse types of waste are generated during the sawmilling process. One of them is pine wood shavings (PWSs). This waste can be transformed by pyrolysis into biochar (BC) to produce a sustainable material that can serve as an asphalt binder modifier. In this study, a BC produced with PWS as biomass (BC-PWS) was used to modify the properties of an asphalt cement (AC). This type of BC has not been investigated as a modifier of ACs and asphalt mixtures. Three BC-PWS contents were used for this purpose (BC/AC = 5, 10, and 15% by weight). Conventional characterization tests such as penetration, softening point, and rotational viscosity were performed on the unmodified and modified ACs. Rheological properties were also evaluated at high and intermediate temperatures, and observations were made with a scanning electron microscope (SEM). The modified BC/AC = 10% binder was chosen to manufacture a hot-mix asphalt (HMA). Marshall, indirect tensile strength—ITS, Cantabro, resilient modulus (RM), permanent deformation, and fatigue resistance (under stress-controlled mode) tests were performed on the HMA. The Tensile Strength Ratio (TSR) parameter was determined from ITS tests. BC-PWS is a promising material as an AC modifier from the technical-environmental point of view, which tends to enhance the evaluated properties of AC and HMA (monotonic load, rutting, fatigue, moisture damage, and raveling resistance), without resorting to increases in asphalt content or increases in mixing and compaction temperatures.

Validation of a generic finite element vehicle buck model for near-side crashes

Objective Finite element (FE) reconstructions of motor vehicle crashes using human body models are effective tools for developing a better understanding of occupant kinematics and injuries in real-world lateral crash conditions, but current near-side reconstruction methods are limited by the paucity of full-scale FE vehicle models. The objective of this study was to validate a generic vehicle model equipped with left-side airbags and intrusion capability by simulating a series of near-side crash tests for a range of vehicles and assessing model accuracy using objective evaluation methods. Methods Moving deformable barrier crash tests were reconstructed for five common vehicle classifications (compact passenger, mid-size passenger, sport utility vehicle, pickup truck, and van) using an updated version of a previously developed simplified vehicle model. Unknown vehicle and intrusion properties (pretensioner force, seatback airbag pressure, curtain airbag pressure, door panel stiffness, ratio of dynamic-to-static intrusion, intrusion velocity, and intrusion scaling factor) were estimated by parameterizing them across 224 simulations per crash test using a Latin hypercube design of experiments. Model accuracy was assessed for 13 anthropomorphic test device signals using the Correlation and Analysis (CORA) objective rating method and injury metric comparisons. Results Maximum ratings of 0.69, 0.67, 0.52, 0.52, and 0.62 were achieved for the compact passenger, midsize passenger, sport utility vehicle, pickup truck, and van classifications, respectively. On average, the abdomen displayed the most accurate behavior (0.51 ± 0.12), followed by the thorax (0.50 ± 0.10) and head (0.50 ± 0.07). The pelvis displayed the least accurate behavior (0.46 ± 0.18) of any region. Reconstructions overpraedicted injury metrics in all cases. Conclusions All vehicles achieved “fair” biofidelity ratings and the compact passenger and midsize passenger vehicles achieved “good” biofidelity ratings, validating them for kinematic evaluations with vehicle-to-vehicle nearside crash reconstructions. Regression models were developed for injuries and CORA ratings and can be used to optimize vehicle parameters in future studies.

Reliability and Validity of the Orthotic Deformation Test

The aim of this study was to evaluate the validity of an orthotic deformation test on insole arches and the impact of researcher expertise on the test’s reproducibility. Three researchers with different levels of experience evaluated orthotic deformation by applying a vertical force with their thumb on the dorsal surface of 48 polypropylene orthoses. An electromechanical test machine was used to evaluate the stiffness of the orthoses, and the results were compared with those of the orthotic deformation tests. Fleiss’ kappa and weighted kappa and Mann–Whitney U tests were used to evaluate the interobserver reliability and the validity, respectively. There was no consensus among the three researchers (Kappa = 0.080; p-value = 0.334), although the two researchers with higher levels of experience exhibited moderate consensus (Kappa = 0.52; p-value &lt; 0.001). Orthoses characterised by a positive test suffered from more pronounced deformation when a constant vertical force was applied by the electromechanical test machine (5.62 [4.64–7.38] vs. 4.56 [3.59–5.28] mm; p-value = 0.003). The orthotic deformation test is valid for interpreting the degree of deformation of polypropylene custom orthoses when it is compared with an axial force from a compression-device test. However, considering the high dispersion of the results, it suggests that clinical experience is required to properly interpret the tests.