Shear Angle Research Articles

Modelling cutting force for turning AISI 304 stainless steel with PVD-AlTiN coated, PVD-AlTiN coated-microblasted, and MTCVD-TiCN/Al2O3 coated tools

ABSTRACT Stainless steel is challenging to machine, and to avoid any negative consequences, it is essential to comprehend the cutting forces. With this view, this study has developed a cutting force model for turning AISI 304 stainless steel with the most preferred PVD-AlTiN coated (C-type), PVD-AlTiN coated-microblasted (CMB), and MTCVD-TiCN/Al2O3 coated carbide tools (MTCVD). Empirical models are developed to predict the chip thickness ratio, the normal shear angle, and sharp tool cutting forces. Studies showed the reduction in forces with the cutting speed for C-type, CMB, and MTCVD tools was 12–20%, 11–32%, and 6–29%, respectively. However, the corresponding increases with the feed and depth of cut were 60–134%, 125–146%, and 97–178%; 76–186%, 55–384%, and 14–274%, respectively. Additionally, a cutting force model considering the tool wear effect is developed for MTCVD tools, which exhibited lower tool wear compared to other tools. The study accurately predicted sharp tool and worn tool cutting forces, showing good quantitative agreement with experimental results with an average error of less than 10%. However, some discrepancies were observed beyond the flank wear length of 0.2 mm. It was due to the chipping of the coating layers and the pitting of the substrate from the nose area.

KEMIRINGAN LERENG YANG TEPAT UNTUK MENCEGAH KELONGSORAN DI DESA BARENG KECAMATAN SAWAHAN KABUPATEN NGANJUK

<p><em>Sawahan District is one of 25 sub-districts in Nganjuk Regency, East Java, Indonesia. Sawahan District has quite good agricultural and tourism potential. Recently, landslides have hit several areas in Nganjuk Regency, one of which is Sawahan District. The area has the potential for landslides because it is dominated by hilly areas with steep slopes and high rainfall intensity. The impact of this disaster included road access that was cut off between the village and the sub-district and the main road leading to the Sedudo Waterfall tour. This study aims to identify soil properties, soil consistency, shear angle, and slope safety factor. The method used is the Atterberg limit test, sieve analysis, soil shear strength, and slope stability calculations using the Bishop method. The test results show that the soil is classified as CL with low plasticity and shear angle, in wet soil it produces a shear angle value of 19.74° and an Fs value of 0.20 while in dry conditions it produces a shear angle value of 24.86° and an Fs value of 0.28. Based on the analysis it is suggested that the slope is 50° to achieve Fs 1.09. This research can be used as a basic reference for planning before construction is carried out and provides slope slope design recommendations for slope planning that is safe to prevent landslides.</em></p>

Determination of the In-Plane Shear Behavior of and Process Influence on Uncured Unidirectional CF/Epoxy Prepreg Using Digital Image Correlation Analysis

The investigation of the in-plane shear behavior of prepreg is crucial for understanding the generation of wrinkles of preforms in advanced composite manufacturing processes, such as automated fiber placement and thermoforming. Despite this significance, there is currently no standardized test method for characterizing uncured unidirectional (UD) prepreg. This paper introduces a ±45° off-axis tensile test designed to assess the in-plane shear behavior of UD carbon fiber-reinforced epoxy prepreg (CF/epoxy). Digital image correlation (DIC) was employed to quantitatively track the strains in three dimensions and the shear angle evolution during the stretching process. The influences of the temperature and stretching rate on the in-plane shear behavior of the prepreg were further investigated. The results reveal that four shear characteristic zones and wrinkling behaviors are clearly distinguished. The actual in-plane shear angle is significantly lower than the theoretical value due to fiber constraints from both the in-plane and out-of-plane aspects. When the off-axis tensile displacement (d) is less than 15.6 mm, the ±45° specimens primarily exhibit macroscale in-plane shear behavior, induced by interlaminar interface shear between the +45° ply and −45° ply at the mesoscale. The shear angle increases linearly with the d. However, when d > 15.6 mm, fiber squeezing and wrinkling begin to occur. When d > 29 mm, the in-plane shear disappears in the completely sheared zone (A). The reduction in the resin viscosity of the CF/epoxy prepreg caused by increased temperature is identified as the primary factor in lowering the in-plane shear force resistance, followed by the effect of the increasing resin curing degree. Higher shear rates can lead to a substantial increase in shear forces, eventually causing cracking failure in the prepreg. The findings demonstrate the feasibility of the test method for predicting and extracting uncured prepreg in-plane shear behaviors and the strain-rate and temperature dependency of the material response.

PLANNING FOR RETAINING WALLS ON THE TANJUNG PAKIS AJI JEPARA VILLAGE ROAD

Retaining walls are a ground control technique that is very necessary to overcome landslides. As happened in the Tanjung Pakis Aji village area. It has steep slopes and there are indications that landslides often occur during the rainy season. The soil parameters that need to be known to plan soil retention walls for testing include specific gravity (Gs); 2.65 kN/m2, void number (e); 33.9, porosity 97.14, shear angle φ ; 29.71 ˚, soil cohesion (c) 24.5 kN/m2, dry soil volume weight (yd ) ; 1.18 kN/m3, wet soil volume weight (yb); 1.87 kN/m3, air content (Wn); 15.29%. Dimensional calculations, stability control, reinforcement of retaining walls are very important in planning retaining walls. The aim of this research is to plan a retaining wall at this location using a cantilever type retaining wall. The results show that the cantilever type retaining wall with dimensions H = 7 m, B = 3 m, T = 0.4 m, Tt and Th = 0.5, Lt = 1, Lh = 1.m, the cantilever is declared safe for the condition of the soil with a safety factor value of Fgs = 4.061 (safe), Fgl = 2.57 (safe), F carrying capacity = 6.62 (safe). From these calculations, reinforcement of types D19-250, D19-200, D19-200 can be obtained, with shrinkage reinforcement D13-100, D13-200.

Mine Landslide Management Sustainability Model in Kutai Kartanegara Regency, East Kalimantan, Indonesia

This research aims to identify the geological and lithological structures of mine land, determine the slope stability of the land, and determine the sustainability of landslide management in Kutai Kartanegara Regency, East Kalimantan, Indonesia. This present research was conducted in Samboja and Sebulu sub-districts, Kutai Kartanegara Regency, East Kalimantan, Indonesia. Data collection concerning the geological structure, lithology, and sustainability of coal mine landslides was carried out. Rock data, such as its physical and mechanical properties, were taken from complete coring drilled and then analyzed in a geomechanics laboratory. This procedure was carried out in three locations, with the first and second samples collected in the Kampungbaru Formation representing the youngest formation. In addition, the third taken in the Pulubalang Formation represents the oldest coal-bearing formation. The data relating to the avalanche condition were collected through surveys, interviews, and filling out questionnaires using a purposive sampling method. The respondents were 13 mining engineering heads from various mine sites in Kutai Kartanegara Regency, three mining environmental experts, and four academics. The results showed that of the 50-joint data, those with potential positions for landslides were located at N333°E/61° and N110°E/74°. The most dominant lithology in the study area was claystone, followed successively by sandstone, siltstone, and shale, with a specific gravity between 2.55 and 2.66. The dominant claystone indicated a relatively prone area. Meanwhile, the strength of the mechanical properties of the rock (direct shear) cohesion ranged from 17.80 and 174.53 kPa, with shear angles ranging from 10.88° to 42.01°. Based on the design of the slope stability in the three locations, this study demonstrated the maximum slope angle ranging from 29° to 37°, a height of 50.17 to 70.16 meters, a single slope height of 10 meters with an angle ranged from 32° to 44°, and a factor of safety (FOS) ranging from 1.326 to 1.452 with stable conditions. Multi-dimensional scaling (MDS) simulation results of the sustainability status comprised of a total of 49 attributes derived from five dimensions, namely ecological, economic, social, law, institutional and technological, demonstrated a score fell of 50.01. Furthermore, to increase the sustainability score, this study identified some sensitive factors as follows: condition of the slope of the mine slope, MSME business of residents, role of NGOs in mine landslides, concern of pit supervisory personnel for mine landslides, and mastery of mine landslide technology. Hence, the projection sustainability score increased to 82.00, which was achieved in the good category.

Parker Solar Probe Observations of Magnetic Reconnection Exhausts in Quiescent Plasmas near the Sun

Parker Solar Probe observations are analyzed for the presence of reconnection exhausts across current sheets (CSs) within R < 0.26 au during encounters 4–11. Exhausts are observed with nearly equal probability at all radial distances with a preference for quiescent Tp < 0.80 MK plasmas typical of a slow-wind regime. High Tp > 0.80 MK plasmas of a fast wind characterized by significant transverse fluctuations rarely support exhausts irrespective of the CS width. Exhaust observations demonstrate the presence of local temperature gradients across several CSs with a higher-Tp plasma on locally closed fields and a lower-Tp plasma on locally open field lines for an interchange-type reconnection. A CS geometry analysis directly supports the property that X-lines bisect the magnetic field rotation θ-angle, whether the fields and plasmas are asymmetric or not, to maximize reconnection rates and available magnetic energy. The CS normal width d cs distributions suggest that a multiscale reconnection process through nested layers of bifurcated CSs may be responsible for observed power-law distributions beyond the median d cs ∼ 1000 km with an exponential d cs distribution present for ion kinetic dissipation scales below this median. Magnetic field shear θ-angles are essentially identical at R < 0.26 and 1 au with medians at θ ∼ 55° near the Sun and θ ∼ 65° at 1 au. In contrast, the tangential flow shear distributions are different near and far from the Sun. A bimodal flow shear angle distribution is present near the Sun with strong shear flow magnitudes. This distribution is modified with radial distance toward a relatively flat distribution of weaker flow shear magnitudes.

Influence of in-plane bending behaviour on textile composite reinforcement forming

The deformation of textile composite reinforcement is influenced by its fibrous composition. In-plane bending behaviour is an inherent aspect of textile reinforcement, yet it is frequently overlooked. The paper elucidates the significant influence of in-plane bending behaviour on fibre orientation during forming process and emphasizes the necessity of accounting for in-plane bending virtual work to prevent non-physical deformation mode. To this purpose in-plane bending calculation is implemented into a fibrous shell finite element by using the neighbouring elements method. Numerical spurious mode involving in-plane shear is avoided due to the new approach. Finally, the model is validated by comparing with composite reinforcement draping experiments: fibre orientations and distributions of shear angles are simulated in good agreement with experiments and give better results than the simulations neglecting the in-plane bending behaviour.

Modeling and Optimization of Turning Hastelloy C-276 under Sustainable Machining Environments

Due to their numerous applications in the aerospace, chemical, and nuclear power industries, environmentally responsible superalloy machining is a major problem in the current production environment. Additionally, Ni-based superalloys are regarded as difficult to manufacture because of their great strength under hot and chemically reactive settings. Therefore, it is necessary to machine these materials using adequate cooling and lubricating solutions. Current study has been based on the optimisation and modelling of turning Hastelloy C-276 under dry, flood, and least lubrication system. A Taguchi L-9 arrangement was used as plan of experiment and modeling was enabled through ANOVA, regression analysis and Taguchi optimization. The results depicted optimal parameters for surface roughness and temperature at v2-f1-d1-CE3 and v1-f2-d1-CE3. Likewise, for CRC and shear angle the best combination was observed at v3-f3-d2-CE2. From ANOVA analysis, the benefaction of C.E, depth of cut and feed rate on S.R been listed as 46.70%, 40.44% and 10.66%. Likewise, for temperature cutting speed has benefaction of (53.09%), cooling environment (23.94%), depth of cut (6.10%) and feed rate 5.49% . In similar fashion, CRC and Shear angle were influenced by feed rate and cutting speed having contribution of 62.89% and 5.15% respectively. Furthermore, minimum standard error between the fitted and observed values for S.R., temperature, CRC, and shear angle were calculated as 0.0149, 7.66, 0.267, and 1.80 units. Finally, the marginal reduction of cutting temperature and surface roughness through utilization of MQL implies the sustainable machining conditions.

The 6th Victor de Mello Goa Lecture: Development of large direct shear facility for geotechnical characterization and stability assessment of opencast mines dumps

As opencast coal production increases, a crucial challenge is safeguarding the stability and management of overburden dumps while prioritizing both safety and cost-efficiency. Determining the optimal stable dump slope dimensions during and after mining remains a key challenge for mining operations worldwide. Assessing the stability of overburden (OB) dumps is necessary to maintain them at the steepest possible angle without compromising stability. Understanding the shear strength, including cohesion and angle of internal friction, of the heterogeneous dump mass is crucial for this assessment. To evaluate the shear strength behaviour of OB materials, a large direct shear machine (LDSM) was designed and developed at Central Mine Planning and Design Institute, Ranchi. The LDSM features a shear box with dimensions of 1000 mm × 1000 mm × 1000 mm to facilitate testing materials with larger particle sizes. It can test large specimens with a thickness up to 500 mm and a maximum particle size (Dmax) of 80mm in accordance with ASTM D3080-98. Seven different OB materials from Magadh Coalfields, India were collected and tested for their shear strength. Using the obtained shear strength parameters, various slope profiles are assessed for stability using 2D limit equilibrium software such as Slide2 and GALENA. Probabilistic modelling is employed to generate a statistically distributed factor of safety (FoS) instead of a deterministic value, accounting for uncertainties related to input parameters. This paper aims to forecast the maximum safe height for OB dumps based on the determined shear strength parameters.

Seismic resilient steel moment connections with top shear tabs and bottom replaceable metallic fuse: Analytical and experimental study

A new seismic resilient steel moment connection with top shear tabs and bottom replaceable metallic fuse is proposed. The shear tabs are realized by a combination of shear angles, with or without shear plates or splice plates, while a buckling-restrained plate (BRP) is employed as the fuse. Both the shear tabs and BRP are placed at a splice location which represents the beam inflection point under gravity load. Analytical models were developed to determine the stiffness, strength, and deformation of the proposed connection, as well as a trilinear moment-rotation relationship at the spliced section. In this way, a coordinated seismic design procedure to achieve structural serviceability and resilience in steel moment frames with the proposed connection was derived based on the equal-stiffness and zero-moment strategies. Cyclic loading tests of full-scale beam-to-column subassemblies equipped with the proposed connection were conducted. Three resilient connections with different shear tabs (bolted/welded shear angles above/below the beam top flanges) were examined and compared with a conventional fully welded connection. The test results validated the concept and confirmed success of the analytical and design methods to ensure sufficient lateral stiffness and concentrate plastic damage into the BRP. Moreover, the resilient connections with bolted or welded shear angles above the beam top flanges exhibited about 11–18% higher moment resistance at 4% drift and 20% more energy dissipation, and thus are recommended over that with welded shear angles beneath the beam top flanges.

ANALISIS PENYELIDIKAN KARAKTERISTIK TANAH KOTA DENPASAR MENGGUNAKAN METODE BOR TANGAN, DAN UJI LABORATORIUM

ANALISIS PENYELIDIKAN KARAKTERISTIK TANAH KOTA DENPASAR MENGGUNAKAN METODE BOR TANGAN, DAN UJI LABORATORIUM

Effects of grain boundary and gradient structure on machining property of CoCrFeMnNi alloys

CoCrFeMnNi high-entropy alloy (HEA) has a high degree of thermodynamic stability and excellent ductility, making it a crucial structural material. However, the plastic deformation and microstructural behavior of gradient grain structured CoCrFeMnNi HEA under cutting remain unclear. In this study, the machining properties of gradient nanostructured CoCrFeMnNi HEA under conventional cutting were investigated by molecular dynamics simulation. The results displayed that the small grain gradient samples exhibited grain size softening. The shear angle and cutting ratio increased with the increase in the grain gradient. The grain boundaries of the low grain gradient samples were damaged and slid during the cutting process. Moreover, the dislocation density increased with the increasing grain gradient. The multi-dislocation nodes and the Lomer–Cottrell junction were produced in the grain coarsening gradient samples, contributing to work hardening. The cutting forces from low to high cutting velocities were 136.70, 147.91, 165.82, and 164.79 nN, which confirmed that the cutting forces increased with increased cutting velocity. This work elucidated the cutting mechanism of the nanostructured CoCrFeMnNi HEA and highlighted the influence of the gradient grain sizes.

Evidencia de una deformación rotacional varisca a partir de braquiópodos distorsionados (Meseta, Marruecos)

En 2021-2022, las obras de construcción de la carretera costera R322, que conecta la Kasbah de Oudayas (Rabat) con la localidad costera de Bouznika, han hecho posible estudiar esquistos con braquiópodos (Spirifer sp.) del Viseense sup. en la playa de Val d’Or, 12 km al suroeste de Rabat. El análisis estructural de las muestras recogidas indica una deformación de los fósiles en el plano XY del clivaje pizarroso (S1), afectados por pliegues recumbentes de vergencia oeste y por una foliación de crenulación (S2) asociada a los pliegues. Los fósiles de Spirifer sp. son triangulares, con forma de mariposa, y tienen el interés de mostrar simetría bilateral en el estado no deformado, con dos direcciones perpendiculares en T (seno o línea de simetría y charnela). Después de la deformación, estos ejes se cruzan con un ángulo agudo / obtuso que indica una deformación angular. Las medidas de los ángulos de cizalla nos llevan a reconstruir el círculo de Mohr para ángulos en el estado deformado, con objeto de obtener la forma de la elipse de deformación finita y determinar los mecanismos responsables de la distorsión utilizando el diagrama de forma de las elipses. Este método permite determinar la relación axial de la elipse de ladeformación finita mediante los círculos de Mohr. Los resultados se comparan con los obtenidos por el método de Wellman y el ábaco de Breddin. Finalmente, se propone un modelo estructural que explica las deformaciones dúctiles observadas como desarrolladas dentro zonas de cizalla dextras de dirección N-S.

In-plane Shear Behaviour of Novel Thick Stitched Textile Reinforcements Part II: Quantitative Analysis of Shear Locking Angle

A quantitative analysis of the in-plane shear test results reported in PhD thesis of Hafeth Bu Jldain was preformed in this paper. Analysis of the results was conducted from experimental and analytical bases. It was conducted experimentally through comparing the results obtained for uO-APT samples with the results obtained for samples made from an industrial fabric manufactured by GmbH Saertex. The analytical validation was conducted through systematic Taguchi plans. These plans investigate, the effect of the type of reinforcement (A and B), the effect of the number of layers, and the effect of stitching setup (R-45, R+45, R0 and R90) on the behavior of the reinforcements. The plans primarily analyzed the extent to which the reinforcement may shear and the force required to do so.Shear test results for stitching orientation R-45 and R+45 show the ability of the new fabric to shear under lower shear forces, which ranged between 0 N and 25 N needed to shear uO-APT reinforcements to shear angles ranging from 50° to 55° before wrinkling was observed.

Machinability of Inconel 718 using unitary and hybrid nanofluids under minimum quantity lubrication

ABSTRACT In the current study, unitary and hybrid nanofluids are used with minimal lubrication to examine Inconel 718’s machinability. Nanofluids are obtained by dispersing unitary and mixed amounts of aluminium oxide, multi-walled carbon nanotubes, and graphene nanoparticles into palm oil. Initially, turning experiments were performed with pure palm oil and different unitary and hybrid nanofluids using differently coated carbide tools to obtain the best combination of the type of nanofluid(s) and coated tool for the lowest tool wear. Further, the cutting forces, surface roughness, chip thickness ratio, chip morphology, and shear angle were obtained, varying with the cutting parameters for the best combination of nanofluid(s) and the tool. The analysis of worn-out tools has been performed through images captured using optical and scanning electron microscopes. The study indicates that aluminium titanium nitride-coated tools outperform titanium aluminium nitride-coated tools with hybrid aluminium oxide and multi-walled carbon nanotube-based nanofluid, followed by a unitary aluminium oxide-based nanofluid. It could be attributed to the higher thermal conductivity and surface tension of aluminium oxide nanoparticles and the better lubricating and cooling capabilities of multi-walled carbon nanotubes. Comparatively lower performance was observed with graphene-based nanofluid due to severe agglomeration that adversely affected the homogeneity of the fluid.

Solar Wind Current Sheets: MVA Inaccuracy and Recommended Single‐Spacecraft Methodology

AbstractWe present the analysis of 1,831 current sheets (CS) observed aboard four Cluster spacecraft in a pristine solar wind. Four‐spacecraft estimates of the CS normal and propagation velocity are compared with different single‐spacecraft estimates. The Minimum Variance Analysis (MVA) of the magnetic field is shown to be highly inaccurate in estimating the normal. The MVA normal often differs by more than 60° from the normal obtained by multi‐spacecraft timing method, likely due to ambient turbulent fluctuations. In contrast, the cross‐product of magnetic fields at the CS boundaries delivers the normal with an uncertainty of less than 15° at the confidence level of 90%. The CSs are essentially frozen into plasma flow, since their propagation velocity is consistent with local ion flow velocity within 20% at the confidence level of 90%. The single‐spacecraft methodology based on the cross‐product method and frozen‐in assumption delivers the CS thickness and current density amplitude within 20% of their actual values at the confidence level of 90%. The CSs are kinetic‐scale structures with half‐thickness λ from a few tenths to tens of local proton inertial length λp and scale‐dependent shear angle and current density amplitude, and . The classification of the CSs in terms of tangential and rotational discontinuities remains a challenge, because even the four‐spacecraft normal has too large uncertainties to reveal the actual normal magnetic field component. The presented results will be valuable for the analysis of solar wind CSs, when only single‐spacecraft measurements are available.

Study of Residual Soil Permeability Coefficient Post Addition of Coal Fly Ash

Residual soil is soil that is often used as barrier cover soil at the closure of B3 waste storage facilities. This is because the shear strength of the soil is quite good. The minimum value of the soil permeability coefficient (k) for barrier hoods at the closure of B3 waste storage facilities is 10-7 cm/sec. Many residual soils have a soil permeability coefficient (k) of less than 10-7 cm/sec. Because the dominant compound in coal fly ash is silica, mixing this fly ash with residual soil can reduce the value of the soil permeability coefficient (k) and is also expected to increase the shear strength value of the soil. In this study, residual soil samples were mixed with fly ash at 5%, 10%, 15%, 25% and 35% of the dry weight of the soil. This research aims to determine the effect of adding fly ash on the parameters of dry density, shear strength and soil permeability. The tests carried out were standard proctor testing, direct shear test, and Falling-Head permeability testing. The residual soil used in this research came from Hamlet I, Bintang Meriah Village, Pancur Batu District, Deli Serdang Regency. Based on standard proctor testing, the maximum density (gd max) of original soil is 1,410 gr/cm3. The largest maximum density (gd max) was obtained when adding 15% fly ash, namely 1.471 gr/cm3. In the direct shear test, the original soil cohesion value was 0.024 kg/cm² with an internal shear angle of 37.96º. In the variation of adding 15% fly ash, the cohesion value was 0.131 kg/cm² with an internal friction angle of 53.08º. Based on the Falling-Head permeability test, the original soil permeability coefficient value was 1.98 x 10-6 cm/s. The permeability coefficient value for variations in adding 15% fly ash was obtained at 8.02 x 10-8 cm/s.

Advanced prediction of soil shear strength parameters using index properties and artificial neural network approach

This study embarks on developing predictive models for soil shear strength parameters, cohesion (c) and angle of internal friction (ϕ), in Bishoftu town, employing Artificial Neural Networks (ANN). It aims at offering a cost-effective and time-saving alternative to traditional, often expensive, and labor-intensive laboratory methods. The research utilizes soil index properties such as Sand %, Fines %, Liquid Limit, Plastic Limit, and Plasticity Index to construct separate ANN models for c and ϕ. These models use a multi-layer perceptron network with feed-forward back propagation, varying the number of hidden layers to optimize performance. The study's dataset comprises 316 soil test results, encompassing both primary and secondary data, conforming to ASTM Standards. Soil cohesion and internal friction angle were determined using the direct shear box method. The models demonstrated remarkable success in predicting shear strength parameters, evidenced by correlation values of approximately 0.99 for cohesion and 0.98 for internal friction angle, surpassing the capabilities of existing empirical methods. Further examination of the models included comparison with existing correlation techniques and cross-validation using primary soil test data. This validation process confirmed the ANN method's superior accuracy and fit for predicting shear strength parameters over selected empirical methods. This research substantiates the efficiency of ANN in geotechnical engineering, particularly for areas with limited resources for extensive soil testing. It establishes ANN as a powerful, efficient tool for estimating soil shear strength parameters, with significant implications for future planning, design, and construction projects in similar environments.

An Angle‐Sensitive Microcolumn‐Based Capacitive Shear Force Sensor for Robot Grasping

AbstractShear force sensors play an indispensable role in tactile perception for robot manipulation tasks. However, recent advancements in shear force sensors have been hindered by issues such as direction sensitivity and integration limitations. This paper proposes a microcolumn array dielectric layer produced using photolithography technology that enables tunability of sensor sensitivity and detection range by adjusting the aspect ratio and interval of the microstructures. Meanwhile, the impact of five constant normal force couplings on the sensitivity of shear force perception is investigated. The structure array with a 1:2 aspect ratio and 600 µm interval demonstrates an ultrahigh sensitivity of 6.189 N−1 and outstanding linearity (R2 = 0.9873) within the range up to 0.1 N. The sensor exhibits low hysteresis and robust stability over 3000 cycles. Additionally, it exhibits remarkable anisotropic direction sensitivity, enabling accurate positioning within a quarter‐circle angle. An intentionally designed orthogonal array is employed to extend the shear angle range up to 360°. Owing to the high performance of the sensor, it is further integrated onto a gripper to facilitate the grasping operation and effectively capture delicate movements. The experimental outcomes highlight that the designed sensor holds promise for applications in robotic applications and electronic skin domains.

Ultra-high temperature transverse and longitudinal compressive properties and failure mechanism of fine woven pierced C/C composites up to 2000 °C

Under ultra-high temperatures up to 2000 °C conditions, the effect of temperatures on the transverse and longitudinal compressive properties and failure mechanism of fine woven pierced C/C composites (FWPCCCs) was revealed. Results showed that the Y- and Z-direction compressive strengths and modulus increased dramatically with the increase of temperature. FWPCCCs had better compression properties at ultra-high temperatures. The Y-direction compressive strength and modulus at 2000 °C increased by 95.24 % and 62.40 %; the Z-direction compressive strength and modulus increased by 51.70 % and 61.94 %, respectively. As the temperature increased, the shear angle of the Y-direction compression failure fracture became larger but that of the Z-direction compression became smaller. Failure cracks emerged from the slits around the Z-direction yarns. The crack then continued to expand along the slits around the Z-direction yarn or between the layers of the two-dimensional woven fabric. But at high temperatures, these slits were smaller and the yarns and matrix were more tightly connected, which resulted in better compressive properties of FWPCCCs.