Stress-strain Simulation Research Articles

Failure behavior analysis of oxide film formed on super-heater tubes of boiler during deep peak process

High-temperature components in the supercritical power plant experienced alternating thermal stresses under deep peak regulation, accelerating the cracking and spalling of the oxide film formed on the steam-side of super-heaters and re-heaters. This study employed the corrosion testing and finite element simulations to investigate the failure behavior of oxide films on super-heaters made by heat-resistant steelsT91 and austenitic HR3C during deep peak conditions. The experimental results indicate that the oxide film on T91was a double layer film containing Fe3O4 and Fe-Cr oxides, which was much thicker than that on HR3C. The spalling of the outer oxide film on T91 was more severe than that of HR3C. The analysis of thermal stress-strain under various loads and oxide film thicknesses revealed the significant shear stress between Fe3O4 and Fe-Cr within the oxide film on T91 steel. The significant shear stress caused the bigger strain within the oxide film on T91 steel, causing the spalling of the oxide film. Compared to the strain within the oxide film on T91 steel, the stress-strain within Cr2O3 oxide film on HR3C steel was notably lower than that on T91 steel. The failure behaviors of the oxide film on T91 and HR3C were quantitatively explained through experimental result and stress-strain simulation with the oxide film. The failure models of the oxide film on investigated steels were put forward.

Use digital rock physics to characterize velocity and attenuation signatures of deep cavity-fracture carbonate reservoirs

Abstract Conventional rock physics experiments and well logging analyses face challenges in deep carbonate formation containing meter-scale cavity-fracture system, since it is unfeasible to extract representative samples from targeted formation. In this study, differing from the conventional digital rock models at the core scale, we construct a digital rock model from realistic outcrop images with meter-scale heterogeneity of cavities and fractures. Using a dynamic stress–strain simulation, we investigate how reservoir type, fracture density and spacing, cavity porosity and size, fluid saturation, and connectivity influence wave dispersion and attenuation. By selecting the simulation frequency of 0.3 MHz approximately corresponding to the field seismic measuring frequency of 30 Hz, the simulation results can reflect the realistic seismic velocity and attenuation characteristics of deep carbonate reservoir rocks. We find that the P-wave velocity decreases linearly with increasing fracture and cavity porosity. The P-wave attenuation is sensitive to variations in fracture density but shows limited sensitivity to changes in cavity porosity and size. Fractures with narrower spacing result in higher attenuation when fracture density remains constant. Deep carbonate rocks with cavity-fracture systems saturated with two immiscible fluids display enhanced attenuation compared to fully saturated conditions. The velocity demonstrates an almost linear increase with water saturation, while attenuation initially increases before decreasing at a peak water saturation of 70%–80%. The connectivity between fractures and cavities significantly influences the attenuation behavior. Our simulation results provide valuable guidance for seismic data processing and interpretation of deep carbonate reservoir rocks with cavity-fracture systems.

The effects of pore structure on wave dispersion and attenuation due to squirt flow: A dynamic stress-strain simulation on a simple digital pore-crack model

Squirt flow, a phenomenon typically observed in porous cracked rocks, occurs due to the contrasting compressibility between the pores and cracks, leading to the pore pressure diffusion and dissipation of wave energy. Understanding the influence of pore structure on wave dispersion and attenuation signatures due to squirt flow is essential for interpreting seismic and sonic logging data in various fields of earth and energy sciences, such as hydrocarbon exploration, geothermal energy exploitation, and CO2 sequestration. In this study, we construct a simple digital pore-crack model with varying pore structures and use a dynamic stress-strain simulation approach to characterize wave dispersion and attenuation signatures due to squirt flow. Numerical simulation suggests that, in addition to the commonly considered parameters such as porosity, crack density, and crack aspect ratio, additional pore structure parameters, such as pore size, pore aspect ratio, crack orientation, crack length, and crack width, significantly affect the wave dispersion and attenuation signatures. Increasing the pore size leads to the pronounced enhancement of attenuation magnitude and a decrease in characteristic frequency. We demonstrate that variations in crack length have a pronounced impact on attenuation magnitude, whereas crack width is decisive in controlling the characteristic frequency. Furthermore, it is found that the saturation paths (the gas filling the pore first or gas filling the crack first) considerably affect the velocity-saturation and attenuation-saturation relationship, suggesting that the coupling effects of pore structure and fluid distribution complicate the fluid pressure diffusion and wave attenuation behaviors. The presented results offer insights for deciphering pore structure parameters using attenuation- or dissipation-related seismic attributes.

COMSOL-based fatigue simulation of crankshaft

The crankshaft is the most valuable and precise single component of the automobile engine, and the force of the crankshaft is extremely complex. It works under the combined action of periodic changes of gas pressure, reciprocating inertia force, and torque, and bears huge bending and torsional alternating loads. It is of great significance to study the effects of bending, torsional, and compound loads on the strength and fatigue life of crankshaft. In this paper, a crankshaft simulation model is established according to the fatigue reliability theory, the fatigue reliability of the crankshaft is determined, the fatigue life is analyzed, the stress-strain simulation of the crankshaft is carried out by COMSOL, and the fatigue load spectrum and damage cloud map of the crankshaft are obtained. The results show that the structural parameter that has the greatest influence on the stress and deformation of the transition rounded radius. The position corresponds to the place of the crank pin where maximum stress occurs.

Statistical analysis of the effect of micro-defect size on the low cyclic fatigue and creep fatigue response of 316FR stainless steel using crystal plasticity finite element method

The main purpose of this study is to explore and discuss the effect of micro-defects of different sizes on the low cyclic fatigue (LCF) and creep fatigue (CF) behavior in 316FR stainless steel. From the crystal plasticity finite element (CPFE) perspective, representative volume element (RVE) models including different micro-defect sizes are systematically developed, and an extended Armstrong-Frederick (A-F) nonlinear kinematic hardening rule is used to capture the LCF and CF behavior of the 316FR stainless steel. Statistical probability analysis shows that the relative errors between the macroscopic stress–strain simulation results and the experimental data ranged from 0.24% to 16.52%, indicating that the model has high accuracy. Three fatigue index parameters (FIPs) are used to characterize the degree of fatigue of the material: the standard deviation of strain increases with increasing micro-defect size, and the standard deviation of the maximum strain at CF loads exceeds that at LCF loads by 0.0173; the larger the size of the micro-defects are, the coarser the persistent slip band (PSB) around the defects is; the strain distribution under CF loading is wider than that of LCF, and the strain at 99% of the strain accumulation frequency at CF loading exceeds that at LCF loading by 0.078. These results indicate that the larger the defect sizes are, the higher the degree of fatigue accumulation in 316FR stainless steel is, and that the deformation behavior of the material is more complex under CF loading.

Numerical sensitivity analysis for stress-strain simulation and flow liquefaction assessment of tailings storage facilities using the NorSand constitutive model

With the advent of critical state Soil Mechanics (CSSM), the void ratio began to be recognized as a key parameter, along with the stress state, which defines the mechanical behavior of soils and other particulate geomaterials by using the state parameter. The state parameter is the difference between the current and critical void ratio so that its definition requires the critical state line (CSL) identification. This work presents numerical calibration results, using the NorSand constitutive model, from three sets of triaxial compression tests selected from the literature. The SIGMA/W module of the Geostudio® System was adopted to perform the simulations of the triaxial compression tests, and the results showed adequate fit between real tests and numerical simulations. The parameters necessary for the modeling with NorSand model, defined from the numerical calibration, were used in a stress-strain evaluation of a hypothetical upstream tailings dam. These simulations allowed the evaluation of the differences in the tailings storage facility (TSF) responses in terms of both deformation behavior and flow liquefaction instability. Flow liquefaction instability is described in the literature as a complete loss in shear strength and the development of excessive strains due to the contractive response of tailings when subjected to low confining stress. The results suggest that the use of the NorSand model is, in general, a good option to reproduce the typical strain-softening behavior of such structures. Furthermore, it was clear the high sensitivity of the constitutive model parameters, drawing attention to the importance of best laboratory practices for carrying out triaxial tests to obtain reliable parameters for NorSand modeling.

Auxetic polymer networks: The role of crosslinking, density, and disorder

Low-crosslinked polymer networks have recently been found to behave auxetically when subjected to small tensions, that is, their Poisson’s ratio ν becomes negative. In addition, for specific state points, numerical simulations revealed that diamond-like networks reach the limit of mechanical stability, exhibiting values of ν = −1, a condition that we define as hyper-auxeticity. This behavior is interesting per se for its consequences in materials science but is also appealing for fundamental physics because the mechanical instability is accompanied by evidence of criticality. In this work, we deepen our understanding of this phenomenon by performing a large set of equilibrium and stress–strain simulations in combination with phenomenological elasticity theory. The two approaches are found to be in good agreement, confirming the above results. We also extend our investigations to disordered polymer networks and find that the hyper-auxetic behavior also holds in this case, still manifesting a similar critical-like behavior as in the diamond one. Finally, we highlight the role of the number density, which is found to be a relevant control parameter determining the elastic properties of the system. The validity of the results under disordered conditions paves the way for an experimental investigation of this phenomenon in real systems, such as hydrogels.

The simulation and experimentation of spiral flat bottom engraving

The study uses rigid-plastic finite element (FE) DEFORM TM 3D software to investigate the plastic deformation behaviour of spiral flat bottom engraving. The finite element analysis assumes that the spiral flat bottom is a rigid body. During the engraving process, the deformation causes an increase in temperature and wear inside the blank. The FE analyses investigate the effects of cutting speed, depth of cut, and the feed of the workpiece on the damage, effective strain, stress, temperature, and wear induced within the workpiece. The simulation results confirm the suitability of the DEFORM TM 3D software for modelling the spiral flat bottom engraving. Comparisons of engraving of spiral flat bottom with clockwise and counter-clockwise have been performed. The analysis of following stress-strain simulation has been predicted by machine learning in this study. Eventually, the experiment of spiral flat bottom engraving is used.

Hybrid deposition additive manufacturing: novel volume distribution, thermo-mechanical characterization, and image analysis

The structural integrity of additive manufacturing structures is a pronounced challenge considering the voids and weak layer-to-layer adhesion. One of the potential ways is hybrid deposition manufacturing (HDM) that includes fused filament fabrication (FFF) with the conventional filling process, also known as “HDM composites". HDM is a potential technique for improving structural stability by replacing the thermoplastic void structure with a voidless epoxy. However, the literature lacks investigation of FFF/epoxy HDM-based composites regarding optimal volume distribution, effects of brittle and ductile FFF materials, and fractographic analysis. This research presents the effects of range of volume distributions (10–90%) between FFF and epoxy system for tensile, flexure, and compressive characterization. Volume distribution in tensile and flexure samples is achieved using printable wall thickness, slot width, and maximum width. For compression, the printable wall thickness, slot diameter, and external diameter are considered. Polylactic acid and acrylonitrile butadiene styrene are used to analyze the brittle and ductile FFF structures. The research reports novel application of image analysis during mechanical characterization using high-quality camera and fractographic analysis using scanning electron microscopy (SEM). The results present surprising high tensile strain (0.038 mm/mm) and compressive strength (64.5 MPa) for lower FDM-percentages (10%, 20%) that are explained using in situ image analysis, SEM, stress–strain simulations, and dynamic mechanical analysis (DMA). In this regard, the proposed work holds novelty to apply DMA for HDM. The optimal volume distributions of 70% and 80% alongside fractographic mechanisms for lower percentages (10%, 20%) can potentially contribute to structural applications and future material-based innovations for HDM.

A Comparative Study on the Confinement Models of High-Strength Steel Fiber Concrete

Since the last four decades, the behavior of concrete contains of steel fiber, or often called steel fiber concrete, with a wide range of compressive strength has been carried out. Generally, the results of the experimental program produced a material which has a more ductile compared with normal concrete or concrete without fiber. Due to the ductility properties of the material, it is very suitable for use as an earthquake-resistant structural material. At the same time, the behavior of high-strength steel-fiber concrete has also investigated, one of which is about confined high-strength steel-fiber concrete. Analytical models of confined high-strength steel fiber concrete have been developed in various preliminary studies, with their characteristics derived based on the experimental results. Therefore, this research evaluated the models of confined high-strength steel-fiber concrete proposed by Mansur et al., Hsu and Hsu, and Paultre et al. The evaluation includes stress-strain behavior, strength enhancement of confined concrete (f'cc/f'co) or K value, the increase in confined concrete strain (ε'cc/ε'co), and strain of confined concrete when the stress has dropped by 50 percent against its unconfined strain (εcc50/εc50). The comparison method was carried out using a statistical approach and stress-strain simulation. Evaluation results showed significant predictive differences in confinement models in terms of post-peak behavior and parameters ε'cc/ε’co and εcc50/εc50. Prediction of confinement models on the value of f'cc/f’co to the experimental results has a coefficient of variation above 10%. The result further showed that a modified model of confined high-strength steel-fiber concrete was proposed and able to simulate the stress-strain behavior.

Microstructure reconstruction using fiber tracking technique and pore-scale simulations of heterogeneous gas diffusion layer

Two challenging tasks in pore-scale modeling of a gas diffusion layer (GDL) are realistic microstructure reconstruction and stress-strain simulation to differentiate the heterogeneous materials. This study proposes a novel method for reconstructing a GDL using fiber tracking technique and pore-scale modeling to investigate its stress-strain and anisotropic transport properties. X-ray computed tomography, fiber tracking, and morphological processing techniques were employed to reconstruct a realistic GDL. Pore-scale modeling was performed to compute the stress-strain, gas diffusivity, and electrical-thermal conductivity at different compression ratios. The sensitivity of compression speed and Young's modulus were investigated to balance the accuracy and computing cost of stress-strain simulation. The results showed that Young's modulus of 1 GPa and compression speed of 3 m/s meet the requirements for both accuracy and computational cost. The reconstructed GDL showed good agreements with the experimental data when considering fibers' orientation, length, and curvature. It was found that the stress among fibers was approximately five times higher than binders. The anisotropic ratios of diffusivity and conductivity decreased from 1.35 to 1.25, and 15 to 5, respectively, as the compression ratio increased to 25%. This study can provide accurate predictions and guidelines for GDL design with low stress and high performance.

Stress-strain numerical simulation for a microprofile subjected to orthogonal impact under constrained loading conditions

The present paper aims to describe shape changes in a microroughness model developed for the working surfaces of parts at degrees of deformation commensurate with the height of the original microprofile; to establish how the degree of microprofile upsetting affects its shape under constrained loading conditions; as well as to estimate the stress state of the microprofile by stress intensity. A numerical model describing the surface microprofile of parts was calculated using the ANSYS Workbench environment. Lead, tin, aluminum, and copper were used as microprofile materials. In addition, microprofile upsetting was computer simulated under constrained loading conditions. The valley bottom was found to rise at a 10–20% microprofile upsetting by 0.213–0.275 mm relative to the original profile height, depending on its material. The relative length of the smoothed microprofile section amounted to 0.786–0.925 mm of its original length. The base angle of the deformed microprofile reached 570 and 800 for copper and lead models, respectively. The depth of valleys ranged from 1.4 mm (23% of the original profile height) for lead models and from 1.8 mm (30% of the original profile height) for copper models. In the case of maximum microprofile upsetting, an increase in the yield strength of microrough material from 10 to 60 MPa contributed to a reduction in the base angle of the deformed microprofile, as well as relative length and the vertical rise of microprofile valleys at their highest point. No interlocking of lateral microprofile surfaces was observed. At a 50% upsetting, the stress state of the microprofile exceeded its ultimate strength by 4–8 times. The shape changes simulated for the microprofile from plastic metallic materials are described. The performed numerical simulation correlates well with the experimental results obtained for lead microprofile models. It is worth noting that the complete smoothing of the microprofile is likely to occur through the rise of valleys and the approaching of its lateral surfaces. The study results can be used for designing and manufacturing valve gate assemblies.

Theoretical study of novel B–C–O compounds with non-diamond isoelectronic

Two novel non-isoelectronic with diamond (non-IED) B–C–O phases (tI16-B8C6O2 and mP16-B8C5O3) have been unmasked. The research of the phonon scattering spectra and the independent elastic constants under ambient pressure (AP) and high pressure (HP) proves the stability of these non-IED B–C–O phases. Respective to the common compounds, the research of the formation enthalpies and the relationship with pressure of all non-IED B–C–O phases suggests that HP technology performed in the diamond anvil cell (DAC) or large volume press (LVP) is an important technology for synthesis. Both tI16-B8C6O2 and tI12-B6C4O2 possess electrical conductivity. mP16-B8C5O3 is a small bandgap semiconductor with a 0.530 eV gap. For aP13-B6C2O5, mC20-B2CO2 and tI18-B4CO4 are all large gap semiconductors with gaps of 5.643 eV, 6.113 eV, and 7.105 eV, respectively. The study on the relationship between band gap values and pressure of these six non-IED B–C–O phases states that tI16-B8C6O2 and tI12-B6C4O2 maintain electrical conductivity, mC20-B2CO2 and tI18-B4CO4 have good bandgap stability and are less affected by pressure. The stress-strain simulation reveals that the max strain and stress of 0.4 GPa and 141.9 GPa respectively, can be sustained by tI16-B8C6O2. Studies on their mechanical properties shows that they all possess elasticity moduli and hard character. And pressure has an obvious effect on their mechanical properties, therein toughness of tI12-B6C4O2, aP13-B6C2O5, mC20-B2CO2 and tI18-B4CO4 all increases, and hardness of mP16-B8C5O3 continue to strengthen during the compression. With abundant hardness characteristics and tunable band gaps, extensive attention will be focused on the scientific research of non-IED B–C–O compounds.

A modified constitutive model considering microstructure degradation of Ni-based superalloys and its application to microstructural damage calculation

Microstructure degradation of Ni-based superalloys operating at high temperatures for long terms inevitably occurs, which has a deteriorating effect on the mechanical properties of the alloy. In this study, the Chaboche elastic-viscoplastic constitutive model of a directionally solidified (DS) superalloy was modified by considering microstructure degradation based on the quantitative description of microstructure morphology. The feasibility and accuracy of the modified model were verified by cyclic tensile tests. The finite element stress-strain simulation results using the modified model showed that compared with the virgin superalloy, the pre-coarsening superalloy exhibit more cyclic softening and mean stress relaxation characteristics, which is illustrated by the variation of dislocation movement behavior. Subsequently, the microstructural damage evolution of the turbine blade was simulated based on the microstructural damage calculation framework, which was established by coarsening and rafting kinetic models, and the capability of the framework was verified by the slice metallographic results of an in-service turbine blade. The simulation results showed that the microstructure evolution at the 60–77% span areas of the leading edge and the trailing edge near blade tip should get attention primarily. Besides, the rafting damage is dominant for long-term service while the coarsening damage occurs more in the single-mission spectrum.

Dynamic Simulation of Gear System Based on 2D Space Multibody Physics: A Sustainable Gear Design Approach

The study employed a two-dimensional (2D) space with multibody dynamics as the physics to simulate the dynamic behaviour of intermeshing gears. Both the gear teeth and the gear body were employed to simulate the principal stress and strain as well as the Von Mises stress of the gear system. A pair of meshing teeth were examined from the pinion and the other from the gear for accurate contact stress-strain simulation. The validity of the proposed gear simulation was verified from principal surface stress, Von Mises stress, principal surface strain, elastic strain and total displacement. The results show that the dynamic behaviour of the gear could be attributed to the critical meshing characteristics of the single and double teeth. The peak-to-peak pattern of the Von Mises stress indicates the essential points of stress, which could cause the occurrence of the failure modes. The research of the gear motion study is profoundly enriched and served as a critical reference for gear design.

The stress-strain state simulation for the auger-boring machine’s support-guide system

The article deals with a number of important aspects of the aggregate-modular type auger-boring equipment creation, as an integral part of the range of tunneling complexes for mining operations and laying horizontal and slightly deviated holes for various purposes. The importance of improving the support and guide systems, characterized by a variety of configurations and sizes, a large number of elements for various purposes and with different responsibility degree, is noted separately. In this regard, the possibility of flexible refinement of the complexes configuration for specific boring conditions with the verification of each applied technical solution by computer modeling remains relevant. The ways for a new constructive solutions creating are outlined.

Effects of the Filler Property, Electron–Phonon Coupling on Thermal Conductivity, and Strain Rate on the Mechanical Property of Polyethylene Nanocomposites

Electron–phonon interaction (EPI) plays an important role in the transport property of metals. Nevertheless, EPI in polymer nanocomposites containing metal fillers has not been fully investigated due to the complicated physical mechanisms. In this work, the copper–polyethylene (Cu–PE) nanocomposite is used as a model system, and nonequilibrium molecular dynamics (NEMD) simulation combined with the two-temperature model (TTM) is conducted to reveal the role of EPI in Cu–PE systems. The effects of filler length, filler property, and EPI strength on thermal conductivity are revealed. A dimensionless number (Θ) is defined to characterize the electron–phonon nonequilibrium (EPN) degree. The results show that the EPN degree has a significant impact on thermal conductivity. When the system is in a strong EPN state, the effects of EPI on thermal conductivity can be negligible. However, when the EPN degree gradually decreases, ignoring EPI can severely underestimate the thermal conductivity. Furthermore, the temperature profile of electrons and phonons is extracted and the equivalent thermal circuit is presented. The additional thermal resistances induced by the nonlocal and nonequilibrium effects are revealed. Phonon spectra analysis and heat current decomposition are performed to uncover the underlying mechanisms. In addition, the effects of atomic mass density and filler types on thermal conductivity are revealed. Stress–strain simulation is conducted to unravel the effects of strain rates on the mechanical property. The results are useful for designing polymer nanocomposites with controlled thermal conductivity.

Electromagnetic strain measurements and two-directional mechanical stress estimation for a REBaCuO ring bulk reinforced by a metal ring during field-cooled magnetization

In this paper, simultaneous measurements of the electromagnetic strains along both the circumferential (θ) and radial (r) directions are reported for a large single-grain EuBaCuO ring bulk reinforced by an Al alloy ring during field-cooled magnetization (FCM) from 5 T at 50 K using several strain gauges adhered to the surface. To verify the experimental results and to understand the complex stress–strain behavior, mechanical analyses were carried out using a three-dimensional finite element model that closely represents the experimental setup. The simulation results of the electromagnetic strains along both directions showed excellent qualitative and quantitative agreement with the experimental ones. These results strongly suggest that the numerical model must include the exact same structure (size, shape and materials) of the mechanical support structure as the experimental setup in order to reproduce the experimental results both qualitatively as well as quantitatively. This also explains our previous research (SuST 2019 32 015007), where the measured circumferential strains were about 50% smaller those in the numerical simulation. Furthermore, the electromagnetic stresses along both directions during the FCM process are estimated from the obtained experimental strains. As a result, the estimated stresses were fairly consistent with those obtained by the numerical simulations, suggesting that our stress–strain simulation technique is both qualitatively and quantitatively reliable and useful to clarify the possibility of mechanical fracture of bulk superconductors.

Complete stress–strain constitutive model considering crack model of brittle rock

The microcrack propagation-coalescence mechanism and stress–strain constitutive model of brittle rock is of great significance for prediction of mechanical properties. To establish a more applicable constitutive model of brittle rock, the crack model based on fracture mechanics was introduced. First, based on the crack slip model and maximum circumferential stress theory, a theoretical equation for crack propagation length was established. The microcrack propagation-coalescence mechanism of brittle rock material under loading was studied. On this basis, a macro-coalescence zone model was proposed. Through the relationship between the deformation characteristics of stress–strain curves at different crack growth stages and the behavior of microcracks, a complete stress–strain constitutive model of brittle rock based on the crack model was theoretically deduced. The constitutive model was verified by the results of a coupling hydro-mechanical test of granite carried out after different heat treatment temperatures. The advanced intelligent algorithm, genetic algorithm, was adopted to simulate experimental data. The research results showed that: (1) The derived stress–strain constitutive model of brittle rock is not only high in accuracy of stress–strain simulation, but also can simulate both the axial and circumferential stress–strain curves. Moreover, the dilatancy and crack initiation stresses can be obtained directly. (2) The parameters of the stress–strain constitutive model not only have clear physical meaning, but the mechanisms of rock mechanical properties, such as dilatancy, acoustic emission, and stress fluctuation, can be explained.

Stress-Strain Response Determination during Incremental Step Tests and Variable Loadings on Flat Specimens

For stress-strain response simulations and damage prediction of cyclically loaded mechanical components, it is crucial to determine both the stress-strain and durability curves of the materials sued. Round and flat specimens can be used for this purpose, either following standard recommendations for their geometry or by designing a special geometry which enables special requirements, such as initial cracks of various shapes, attachment of an extensometer, special grips for raised temperatures, and so on. However, especially in the case of flat specimens having a slender shape, buckling can occur before the stress or strain values reach a sufficient magnitude in compression. To avoid this, an anti-buckling support can be attached to the specimen, which prevents the occurrence of buckling. In turn, friction occurs between the specimen and the anti-buckling support, which affects the measurement of the stress. If a special sensor is attached under the anti-buckling support, the friction force can be measured and subtracted from the stress signal, leaving only the stress-strain response of the material under investigation. In this study, two materials were investigated during incremental step and variable loading tests: The aluminium alloy AlMgSi0.5 and a biodegradable polylactide.