Shear Angle Research Articles

The effect of waste marble powder and phosphoric acid on the shear angle and cohesion value of expansive soils

In general, the expansive clay soil is a problematic soil due to the impact of climate change, during the rainy season the soil expands, and during the dry season the soil shrinks and cracks. Of these problems, it is necessary to carry out soil stabilization in order to determine the mechanical properties of the soil using the Waste Marble Powder (WMP) and Phosphoric Acid (PA) chemicals. To improve soil characteristics, tests were carried out with a mixture of 2.5%, 4%, 5.5% and 7% WMP, while Phosphoric Acid was a fixed percentage of 4% for the expansive soil. Curing periods of 3 days,7 days, and 14 days were also conducted in this study. According to the test results, the increase in the shear angle value, from originally 6.45° changed to 29.81° which increased by 21.64% of the percentage of the original soil, while the soil cohesion value, from originally 0.37 kg/cm2 changed to 2.25 kg/cm2 which increase of 16.44% in the curing period of 14 days. This increase is caused by chemical reactions that occur as a result of chemical elements, especially calcium (Ca) and potassium (K) contained in marble powder waste, and the mineral phosphorus (P) contained in phosphoric acid chemicals.

ОДИН ИЗ МЕХАНИЗМОВ ВОЗНИКНОВЕНИЯ ВЫСОКОЧАСТОТНЫХ КОЛЕБАНИЙ ПРИ ТОЧЕНИИ

The article presents the results of theoretical studies of the mechanism of high-frequency oscillations in the cutting zone based on wave processes accompanying the change in the elastic deforming state of the material during its destruction along the shear plane. Based on the studies carried out, it was confirmed that the source of high-frequency self-oscillations generated in the cutting zone is the dynamics of deformation of the material during its destruction along the shear plane. This plane represents the interface of the two media initiating wave processes propagating into the body of the workpiece and chips. Their character and parameters largely depend on the properties of the material being treated (modulus of elasticity and density), the haracteristics of the tool (material, front angle and quality of the front surface) and such operating parameters as the supply to the revolution and the width of the cut. It is noted that the cutting speed affects them indirectly, through the shear angle and the main component of the cutting force. Analytical dependence is proposed, establishing their relationship. It will allow a priori assessment of frequency ranges of possible self-oscillations in order to exclude modes that lead to deterioration of the quality of the treated surfaces.

Shear strength and compressibility of reconstituted Boom clay, a stiff clay from the Paleogene

Boom clay is a stiff marine clay from the Oligocene epoch of the Paleogene period. It outcrops along the rivers Rupel and Scheldt in Northern Belgium, nearby the city and the port of Antwerp. Most of the existing geotechnical investigation around the Antwerp area, where the clay is located at relatively shallow depths, consists of standard laboratory tests on undisturbed samples performed at stress levels around the estimated in situ stress. Although the geological preconsolidation pressure of this clay is relatively well known, the clay yields at much higher stresses in 1D compression. Moreover, due to the brittle behavior of the stiff clay, it is often difficult to evaluate its shear strength behavior beyond peak strength. To this end, evaluating intrinsic parameters of compressibility, critical state shear angle and residual strength is of great relevance. In the present research, the mechanical behavior of reconstituted normally consolidated Boom clay was examined in a series of oedometer, CRS, CU triaxial, and multi-reversal direct shear tests. The mechanical behavior of the reconstituted clay was compared to the behavior of undisturbed clay samples. The results allow for a better evaluation of the structure effects of the natural samples on their mechanical response.

Reconnection Inside a Dipolarization Front of a Diverging Earthward Fast Flow

AbstractWe examine a Dipolarization Front (DF) event with an embedded electron diffusion region (EDR), observed by the Magnetospheric Multiscale (MMS) spacecraft on 08 September 2018 at 14:51:30 UT in the Earth's magnetotail by applying multi‐scale multipoint analysis methods. In order to study the large‐scale context of this DF, we use conjunction observations of the Cluster spacecraft together with MMS. A polynomial magnetic field reconstruction technique is applied to MMS data to characterize the embedded electron current sheet including its velocity and the X‐line exhaust opening angle. Our results show that the MMS and Cluster spacecraft were located in two counter‐rotating vortex flows, and such flows may distort a flux tube in a way that the local magnetic shear angle is increased and localized magnetic reconnection may be triggered. Using multi‐point data from MMS we further show that the local normalized reconnection rate is in the range of R ∼ 0.16 to 0.18. We find a highly asymmetric electron in‐ and outflow structure, consistent with previous simulations on strong guide‐field reconnection events. This study shows that magnetic reconnection may not only take place at large‐scale stable magnetopause or magnetotail current sheets but also in transient localized current sheets, produced as a consequence of the interaction between the fast Earthward flows and the Earth's dipole field.

Optimasi Geometri Lereng dengan Evaluasi Nilai Faktor Keamanan Menggunakan Software Geostudio

The slopes of the Widas watershed in Kutorejo Village, Bagor District, Nganjuk Regency were hit by a landslide, damaging a 50-meter-long road. This damage has an impact on the activities and mobility of residents. The impact of landslides caused enormous losses, both infrastructure damage and loss of life. Several studies have been carried out, in determining slope stability it is necessary to observe at the research location and determine the type of soil, soil consistency, and soil shear strength parameters. This research aims to determine the value of the safety factor (FK) on the slopes of the Widas River. This research began by conducting a case study, including interviews, collecting field survey data, taking soil samples, and laboratory testing. Slope stability analysis was carried out using Geostudio software. The research results show that the soil type is classified as Poorly Graded Sand (SP), and the soil consistency is classified as Non-Plastic soil with a liquid limit of 26.093 and a shear angle of 20° - 30°. Slope improvements were carried out by changing the slope geometry until a slope ratio of 1V:2H was obtained by creating two slope core models. The FK value increased from 1.007 to 1.107 and 1.437 to 1.585 under pore water pressure conditions. Thus, the slope modeling obtained can be used to overcome landslide problems.

Investigation of machinability characteristics of Inconel 713C using new novel honeycomb and broken-parallel texture cutting inserts with graphene-based solid lubricants

The present investigation aims to investigate the machinability performances of graphene solid lubricant (S) deposited on dimple texture (T1-S), novel honeycomb texture (T2-S), and novel broken-parallel textures (T3-S) during dry turning of Inconel 713C has been carried out and compared with dry (D) textured tools (T1-D, T2-D, and T2-D). L24 orthogonal design was used to design the experiments by considering conditions (dry and solid lubricant), textured type, cutting speed, and feed rate. The experimental results reveal that the honeycomb without and with graphene (T2-D and T2-S) effectively reduced the generated cutting temperature by 14.5 % and 22.4 %, cutting force by 34.6 % and 39.4 %, surface roughness by 14.3 % and 22.4 % and tool flank wear by 11.9 % and 2.3 % compared dimple and broken parallel textured inserts. The honeycomb tool (T2-D and T2-S) exhibited shear angle increased by 7.45 % and 6.5 % and 29.3 %, and 33.33 % than dimple under dry and graphene textured cutting tool. The chip reduction coefficient was <1.5, resulting in an increased shear angle and decreased friction coefficient in graphene-deposited honeycomb texture conditions. The major mechanism credited to the improved performance of honeycomb with graphene tool was reduced chip curl diameter and chip width by 3.3 % and 5.7 % compared to other tools. SEM images showed that all textured inserts' primary tool wear mechanisms on the tool surface were built-up edges, micro-chipping, adhesions, and abrasions. EDS analysis and following elemental plotting showed the strong presence of workpiece constituents on the flank surface. But, the influence of adhesion and abrasion was more noticeable for all dry-textured tools. The findings of this study indicate that honeycomb textured tools are a superior alternative to dry machining of Inconel 713C. Additionally, broken-parallel textured tools were more effective than textured dimple tools.

Application of Geoinformatics in Civil Engineering Design and Construction: A Case Study of Ile Oluji, SW Nigeria

Subsoil engineering site condition and modeling of engineering parameters has been carried out in Ile Oluji, Ondo State, Southwestern Nigeria, using geotechnical investigation, geophysical method, borehole logging, groundwater level measurement, and laboratory studies. Findings revealed that the soils are clayey of low-high plasticity/compressibility, with AASHTO classification of A-7-6. Based on average values of cohesion (48.4 KN/m2), angle of friction (17.4°), unconfined compressive strength (186.8 KN/m2), coefficient of permeability (2.13E-06 cm/s), activity (0.48), soaked CBR (7 %), MDD/OMC (1980 kg/m3/14.8 %), plasticity index (20.2 %), group index (6 %), compression index (0.0443), coefficient of volume compressibility (0.2041 m2/KN), depth to basement rock (22.2 m), static water levels 5.5 m (in well) and 21.8 m (in borehole), the soil is unsuitable for highway subgrade, subbase, and base courses. Thus, if it is expedient to use it as subgrade soil, the minimum recommended thickness is 241 – 513 mm (avg. 395 mm). The average allowable bearing capacity of the soil for square and round foundations are 268.4 KN/m2 and 267.95 KN/m2 respectively, with average total settlement of 18.3 mm for structural pressure of 100 KN/m2. For embankment, the suitability index (1.21) of the soil suggests a fair/expanding not collapsible construction material. The rock units in the area have high compressive/shear strength, modulus of elasticity, high crushing strength, low deformability; and presumable bearing capacity of 8, 000 – 10, 000 KPa when fresh, and 5000 – 7000 KPa when partly or slightly weathered. Thus are valuable as foundation constructions, aggregate in pavement, building stone, and armourstones. The correlation coefficient of the parameters are: MDD/PI vs. CBR (0.0043), LL vs. coefficient of consolidation (0.0608), PI vs. undrained shear strength/effective overburden (0.2706), PI vs. angle of shearing (0.0117), dry density vs. angle of shearing (0.0058), suitability index vs. CBRs (0.3644), clay contents vs. PI (0.1355).

Development and validation of an automatic recording microcontroller-based pendulum impact cutter

Knowledge of rice straw bunch in respect of cutting energy is the important factor for optimization of cutting elements in straw chopping system. A micro controller-based pendulum impact cutter was developed during 2019–21 at the ICAR-Central Institute of Agricultural Engineering, Bhopal, Madhya Pradesh. The system was integrated with load cell, adjustable pendulum arm and adjustable shear and approach angle (0–30 degree) during the cutting experiment. In this study, straw bunch cutting energy at the lowest point of Node 3 was examined which is just above the ground surface. Three type of blades SMS serrated, cutter bar and SMS plain blade were used to determine cutting energy. In order to determine the cutting energy requirement of straw bunch, the mechanical and physical properties of straw were determined. The results represent that the cutting force was significantly affected by blade type, shear angle and approach angle. The minimum cutting energy for SMS serrated, cutter bar and SMS plain blade was registered as 120, 189 and 243 J, respectively among all combinations of shear and approach angle. Developed recording type pendulum impact cutter was compared with the traditional method at selected combination of shear and approach angle for all the three blades and the relative error was recorded between 4–6%. It was concluded that with increasing approach angle at constant shear angle the cutting force initially decreased up to 20 degree and rapid increase from 20 to 30 degree of approach angle. Consequently, the SMS serrated blade emerges as the preferred choice for the rotary impact cutter development, showcasing the potential of this research in advancing straw chopping technology.

Evaluasi dan Pengelolaan Lereng Bekas Tambang Breksi Andesit Dusun Siluk Kelurahan Selopamioro Kepanewon Imogiri Kabupaten Bantul Daerah Istimewa Yogyakarta

Siluk Area, Selopamioro Village, Imogiri District, Bantul Regency, Special Region of Yogyakarta, is one of the active community mining sites. These mining activities leave slopes that are not treated or repaired, so that they become a threat to soil and/or rock mass movements for the surrounding community. One of the former mining areas in Siluk hamlet is very close to residential areas. Therefore, it is necessary to study the stability and safety factors of the slope so that they can be the basis for determining the direction of ex-mining slope management.The methods used were literature studies, field surveys and mapping, and laboratory tests. The sampling method used was the purposive sampling method. Samples taken were used for testing physical properties (content weight, moisture content, porosity, and grain size), shear angle, and cohesion. The analysis methods used are the simplified Janbu method and the descriptive analysis method to evaluate the slope of the former mine. Based on calculations and testing, it is found that the three slopes are categorized as steep slopes with a safety factor value on the central and south-north slopes of 0.156, 0.620, and 0.367. Slope management carried out involves a change in slope geometry with the cut and fill method, planting vegetation in the form of Sengon trees, and planting land cover in the form of Vertiver grass

Compression-shear fracture of nickel-based superalloy during rotary tube piercing

Large-diameter nickel-based superalloy seamless tubes are the key component of pipeline transmission system in nuclear power, thermal power and petroleum industries. The rotary tube piercing (RTP) process is suitable to prepare large-diameter seamless tubes. However, the high temperature dynamic compression-shear fracture, also known as separation layer defect (SLD), is inevitable in the RTP process of nickel-based superalloy. In the study, the SLD was systematically studied by the combination of simulation and experiment. Firstly, the isothermal compression-shear experiments were designed to study the fracture behaviors. The results reveal that the plasticity of Inconel 718 alloy decrease with the increase of temperature and strain rate within the range of temperature 1080-1160℃ and strain rate 5–40/s, and the shear angle has significant effects on the fracture behavior. Secondly, based on the isothermal compression-shear experiment results, the SLD was explored by RTP experiments. The results reveal that the compression-shear deformation extent has significant effects on the SLD, and the folding defect is generated before the SLD is observed. The fracture morphology further confirms that the SLD belongs to typical shear fracture, which is generated under specific strain and stress state. Finally, the formation mechanism of SLD is revealed by combining finite element simulation and experiment. It is found that the formation of SLD includes crack initiation and crack propagation. Crack initiation is related with the maximum shear strain and maximum shear stress, and the crack propagation is controlled by radial deformation gradient.

Comprehensive study of material removal mechanism of polycrystalline copper during ultra-precision cutting using molecular dynamics

Nano-polycrystalline copper as a unique functional and structural material has been drawn great attention. Comprehensive study on its nano-cutting mechanism is of great important to guide the ultra-precision machining process. In this paper, nano-cutting simulation of polycrystalline copper was studied against the cutting depth, tool geometry, grain size and grain orientation. The effect of cutting depth on the shear angle of the material deformation and the proportion of HCP atoms in chips were studied. Furthermore, nano-indentation and nano-cutting of polycrystalline copper with different grain size were simulated. In terms of crystal orientation, the difference of orientation in the bi-crystalline copper could form chips with different shapes and induce different strain distribution within the grain. In addition, the size and distribution of dislocation density are studied in the nano-cutting process of different polycrystalline copper textures. Texture {112}<111>, {236}<385>, and {124}<211> were considered.

Stress stateofa composite tractive element with cable rigidity variable over length considering bending on a drum with curved generatrix

Purpose. Establishment of dependencies for parameters of a stress-strain state of a composite tractive element taking into account bending of a rope with cable rigidity variable over length on a drum with a curved generatrix. Research methodology. Development of a method for calculating the influence of a complex of factors on a stress-strain state of a rope by constructing and solving a model of a stress-strain state of a composite tractive element with cable tensile rigidity variable over length, cable base breakages and a non-cylindrical drum shape, using the methods of mechanics of layered composite materials with soft and hard layers. Findings. Analytical dependencies are obtained in a closed form and allow determining the maximum quantitative indicators of a stress-strain state of a rope of a combined structure with a broken cable, rigidity different from the main cables and variable along rope length in a straight rope part and in a part of interaction with a curved drum of a hoisting machine. Analytical dependencies are established for determining the maximum angles of rubber shear between cables, which allows determining the dangerous tangential stresses in a tractive element for cases of flat rope tension, rope bending on a convex drum, and bending on a convex drum of a rope with cables of reduced tensile rigidity. The results of solving the problem of determining the distribution of forces in a rope with cables of different rigidity by the developed method absolutely coincide with the only possible distribution of forces in a sample of three cables, which allows considering the developed algorithm reliable to describe the mechanism of redistribution of forces between cables with different tensile rigidity, including in the event of cable breakage, and the obtained results are reliable. Scientific novelty. A method of calculating the influence of a complex of factors on a stress-strain state of a rope is developed. The dependencies of parameters of a stress-strain state of a composite tractive element are established, taking into account rope bending, which has cable base breakages and cable rigidity variable over length, on a drum with a curved generatrix. Practical significance. A method for determining the indicators of a stress-strain state of a composite tractive element, which has cable base breakages and cable rigidity variable over length, including for bending on a non-cylindrical drum, is developed. This makes it possible to increase the operational safety of a composite tractive element in hoisting and transporting machines, in particular at significant hoisting heights, and also contributes to justifying the use of a rope design as a stay rope in capital structures.

Study on tool wear mechanism and chip morphology during turning of Inconel 713C by textured inserts

The present study aims to analyze the tool wear mechanism and chip morphology during dry (D) and graphene solid-lubricant (S), turning of Inconel 713C with a new novel textured (honeycomb (T2) and rectangular(T3)) and further compare with the textured dimple tool (T1). In addition, the performances were compared with the untextured tool (T0). The machining tests for all conditions were carried out at different levels of cutting speeds (75 m/min and 150 m/min), feed rate (0.1 mm/rev and 0.2 mm/rev), and a constant level of depth of cut (0.5 mm). Honeycomb-textured cutting tools performed better. Improvements of 33.3 % (T1D), 50 % (T3D), and 75 % (T2D) without graphene and 66.6 %(T1S), 75 % (T3S), and 100 %(T2S) with graphene are observed compared to T0. The primary mechanism for the better performance of T2S was the reduced tool chip contact length (8–50 %), chip width (30.4 %), friction coefficient (57.4 %), chip thickness (17.8 %), and higher shear angle (14.2 %) compared to dry textured and untextured tools at the end of tool life. Additionally, the T2S (solid lubricant-impregnated honeycomb) demonstrates a decrease in equivalent chip thickness (19.8 %) and an increase in shrinkage factor (17.2 %) at worn-out tool life conditions at high cutting speed and feed rate. Under the same conditions, T2S has 27.3 % lower cutting force and 36.2 % lower surface roughness of machined workpieces compared to the untextured tool at the end of tool life. The chip micrograph reveals the chips are shorter, and the chip radius is lower for T2S tools with smooth friction tracks and fine deformed lamella on the free surface of the chip. Under SEM, flank wear, adhesion materials, abrasion, micro-chipping coating peeling, and BUE were dominant wear mechanisms. However, T2S tools effectively reduce Ni elements' diffusion and suppress the built-up edge's adhesion by improving friction characteristics at the tool-chip interface region. Lastly, the outcomes of experimental results suggest that the honeycomb texture for dry machining of Inconel 713C.

STUDI NILAI KUAT GESER TANAH HAMBALANG BERDASARKAN KADAR AIR

Soft soils have low strength and easy to compress when they are loaded. A soil compaction test is performed to measure maximum soil density at the optimum water content to evaluate the strength of soft soil. To maintain these circumstances, however, efforts are necessary to preserve the water content at optimal levels, which is not easy. In actual condition the compacted soil can still be penetrated by water through soil cracks occurred especially on the slopes. The shear strength of the soil will decrease if rainwater infiltration is excessive. In a laboratory investigation, direct shear testing (ASTM D3080 - SNI 3420:2016) was used to determine how changes in the value of the Hambalang clay soil shear strength as reflected by the cohesion value (c) and the soil shear angle (f). Creating soil samples with a fixed density and variations in water content (w). The test results at w = 14.47% obtained c = 0.047 kg/cm2, f = 45.75⁰; at w = 21.75% obtained c = 0.203 kg/cm2, f = 33.39⁰, at w = 26.62% obtained c = 0.186 kg/cm2, f = 24.10⁰, at w= 31.59% obtained c = 0.086 kg/cm2, f = 21.90⁰ and at w = 33.70% obtained c = 0.082 kg/cm2, f = 21.21⁰. From these results it can be concluded that the largest of cohesion and angle of internal friction or strength parameter values will reach at optimum moisture content.

Characterisation of the transverse shear behaviour of binder-stabilised preforms for wind turbine blade manufacturing

Binder-stabilised preforms are being used increasingly in the production of large composite structures, such as wind turbine blades, to increase the throughput. The transverse shear behaviour of the preform is one of the driving factors in the development of wrinkling during manufacturing but has not previously been characterised in the literature. In this paper, the combined intra- and inter-ply deformations during transverse shearing of a binder-stabilised preforms for wind turbine blade manufacturing are characterised by a new test methodology. The results from two experimental campaigns are presented. In the first campaign, preform specimens are subjected to monotonic loading to a nominal transverse shear angle of 18.0° with three different deformation rates. The results show an increase in maximum load levels with greater deformation rates. In the second campaign, preform specimens are subjected to deformation-controlled cyclic loading with two different deformation amplitudes corresponding to a nominal transverse shear angle of 1.5° and 12.2°, respectively. During cyclic loading, permanent deformation is observed in all preform specimens and the maximum load at the 19th cycle is reduced to 48% of the maximum load at the first cycle for the tests with deformation amplitudes of 12.2°. The data generated in this study is freely available at https://doi.org/10.17632/9m78sg3zwn.1.

Strain-rate-dependent dynamic compression–shear response of alumina

This research article investigated the stress-state and strain-rate-dependent mechanical properties and failure of alumina ceramic. Compression–shear testing was carried out using a split-Hopkinson pressure bar under equivalent strain rates ranging from 101 s−1 to 103 s−1. Ultra-high-speed images coupled with digital image correlation were used to investigate the in situ time-evolving strain field and the failure process (e.g., crack growth). Experimental results showed equivalent strength reduced from 4.27 ± 0.23 GPa for the uniaxial compression tests to 3.75 GPa and 2.00 GPa for compression–shear tests across the strain rates and shear angles (5° to 25°), with the strength decreasing with an increasing shear angle. The crack speed ranged from 908 m/s to 3208 m/s across the range of strain rates and shear angles, with a positive correlation noted for crack speeds with strain rate and increasing sensitivity with an increasing shear angle. The extent of localization of shear strain in alumina under compression–shear deformation was observed to be strain-rate-dependent, and it increased with an increasing strain rate of deformation. Furthermore, axial and shear strain localization increased with the increasing shear angle, contributing to local shear failure before the complete failure of the specimen. Overall, this paper provides new insights and measurements of the strain-rate-dependent and shear-dependent strength and crack speeds of alumina under compression–shear loading, and these serve as vital inputs for future computational model development and validation.

A Novel Flexible Centralized Force Sensor Based on Tri‐Axis Force Refactoring Method for Arbitrary Force Components Measurement

Flexible force sensors have been widely applied in robotics for object exploring, remote controlling, and human–machine interactions. The tri‐axis force sensors for accurate measurement of normal and shear forces are generally in urgent demand. Most tri‐axis force sensors rely on signal analyzation between multiple elements to achieve force components, which may need numerous leading wires and limit the force angular sensing performance. Herein, a novel flexible centralized force sensor is developed based on a novel tri‐axis force refactoring method. Normal force is detected by the central parallel‐plates capacitor, and both the angle and amplitude of shear force can be extracted through the resistance changes. The normal force performance is characterized with a sensitivity of 0.057 N−1 and a detection range of 0–12 N, and the effective detection range of shear force is about 0.5–0.67 N. The minimum distinguished shear angle difference is about 7.3°, which can be further improved by increasing the sensing material's resistivity. Then, robotic grasping tests are performed and show that the sensor can accurately measure the normal and shear forces and applied shear force angle, which indicates its promising applications in potential robotic manipulation and interactions.

Rotational shearing interferometer and wavefront angular derivative.

A shearing interferometer finds a derivative of the wavefront along the direction of the shear parameter. While the general belief was held that the sensitivity of the RSI increases with the shear angle, we find that just the opposite is true. We examine the range of validity of the derivative function for the rotationally shearing interferometer (RSI). We find that all terms of the aberration polynomial are multiplied by the sine of the half-shear angle multiplied by the order of polynomial, l. This factor may be expanded in series for small angles, or for angles close to π and π/2. We propose steps to evaluate the errors in the determination of the magnitude of individual aberrations. We apply findings to the planet-detection problem.

Experimental testing method to characterise the drapability of UD non-crimp fabrics used in wind turbine blades

This scientific article presents a novel approach for characterising the drapability of fabrics used in wind turbine blade production. This study defines drapability as an intrinsic property of fabric to shear. Specifically, it refers to the potential of the rovings to slide with respect to each other. The evolution of wrinkles has been quantified by the ratio of height-to-width corresponding to a shear angle. The growing industrial interest in binder fabrics, for their preforming ability and improved handling leading to faster blade production, has motivated this study. In this research, two types of non-crimp fabrics, with and without binder, were analysed to study the evolution of wrinkles concerning applied shear angles. A state-of-the-art 3D blue light scanning technique is employed to accurately measure the aspect ratio (height/width) of wrinkles at various shear angles, including 0°, 4°, 6°, 8°, 12°, and 16°. A wrinkle having an aspect ratio of 1/10 was determined to correlate with an applied shear angle of 9° for non-binder fabrics, and 3° for binder-based fabrics. The findings clearly demonstrate the influence of binders on fabric drapability, reducing it by a factor of three. These results provide valuable insights into the influence of different parameters on wrinkle formation, aiding in controlling these factors to avoid manufacturing defects in wind turbine blades.

Laboratory Testing-Based Characterization of Peat in Palangkaraya, Central Kalimantan

Peat is a unique type of soil because it has a very high organic matter content. One of the locations in Indonesia that has the most peat distribution is Palangkaraya City, Central Kalimantan. It is important to understand the characteristics of peat, especially in engineering applications. The characteristics of peat can be known based on laboratory testing, but in practice many tests are not carried out in accordance with the characteristics of the peat. In this paper, laboratory tests will be carried out based on the characteristics of the peat, with a focus on testing the physical and mechanical properties of the soil. Based on the results of the tests conducted, it can be concluded that the Palangkaraya peat is a fibrous hemic peat. The Palangkaraya peat has a water content of 639.5%, ash content of 3.25%, organic content of 96.75%, fiber content of 53.32%, pH of 3.2, content weight of 0.983 gr/cm3, specific gravity of 1.48, cohesion value of 0.138, and inner shear angle of 16.26°. The characteristics of this peat can provide an overview for researchers or the local government to make the best use of peatlands. Further research is needed to find out other aspects outside the engineering field to determine the characteristics of peat in Palangkaraya City, Central Kalimantan.