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The ball defects generated in skew rolling process have restricted to large extent the further application of skew rolling technology in ball manufacturing industry. Research was carried out so as to find the factors and laws of influencing on skew rolling ball quality. It was found by analyzing the forces exerting on the ball that the deforming velocity of ball had the largest influence on the resistance to deformation. Simulations were done respectively under different roller obliquities, different distances between two guide plates, and different rotation speeds of rollers by means of DEFORM-3D software. Finally, the influencing factors and laws on ball quality were discovered.

A method to determine the shoulder height in an angular contact ball bearing using a 3D contact analysis is proposed. The load analysis was performed by calculating the distributions of internal loads and contact angles for each rolling element. From the results of the bearing load analysis and the contact geometry between the ball and raceways, 3D contact analyses using an influence function were conducted. The algorithm developed was applied to an angular contact ball bearing for an automotive wheel. The effects of axial load on contact pressure at the inner and outer raceways were evaluated and the critical axial loads in the present shoulder height were calculated. The critical shoulder heights were also determined when the bearing was subjected to a practical load for a steel ball bearing. The proposed methodology is generally applicable for the purpose of reducing the material cost and improving the efficiency of the bearing design process.

The non-lubricated, ball-on-flat sliding friction and wear properties of in situ (TiB2 + TiC)/Ti3SiC2 composites against bearing steel ball were investigated. The load was varied from 10 to 30 N. The material without TiB2 shows an increasing friction coefficient with the increasing load. However, for (TiB2 + TiC)/Ti3SiC2 composites, the friction coefficient shows an insensitivity to load. Both friction coefficient and wear rate initially increase and then dramatically decrease with TiB2 content increasing from 0 to 20 vol%. (TiB2 + TiC)/Ti3SiC2 composites with 15 vol% and 20 vol% TiB2 show excellent wear resistance, whose friction coefficient and wear rate are much lower than those of TiC/Ti3SiC2 composite. The enhanced wear resistance is mainly attributed to the facts that the hard TiB2 and TiC particles nail the surrounding soft matrix and decentralize the shear stresses under the sliding ball, a self-lubricating oxide debris forms on the wear surface, and the wear mode converts from adhesive wear to abrasive wear.

The positive effects of wearing a mouthguard have been indicated in various epidemiological surveys and experiments, and their usage appears to be increasing in many sports. However, many preventable sports-related dental injuries still occur even with the use of a conventional mouthguard. We have developed a mouthguard (the Hard & Space mouthguard) with sufficient injury prevention ability (more than 95% shock absorption ability against impact with a steel ball carrying 15.2 kg m(2) S(-2) potential energy) and ease of clinical application. This mouthguard consists of an outer and an inner EVA layer and a middle layer of acrylic resin (hard insert), with a space to prevent contact between the inner surface of the mouthguard and the buccal surfaces of the maxillary front teeth or teeth already weakened through prior damage or treatment. The purpose of this article is to describe the method by which the Hard & Space mouthguard may easily be fabricated. We believe that this new type of mouthguard has the potential to reduce sports-related dental injuries.

in order to improve the efficiency and accuracy of steel ball processing, analyze the main influential factors, to propose the new technology and equipments of damping plate system and obtain the new solutions of the efficiency and accuracy of steel ball processing.

Accord to the research on microcosmic mechanism of steel ball grinding, analyze the law of abrasive’s movement on the surface of steel ball, and then establish the elimination process and grinding effect by the analyzes software such as CATIA, establish a general model about how to remove the excess material on steel ball surface, and find the relationship between the influencing factors. With the help of the research above, we can provide a foundation of detailed study and improvement about various processes of grinding ball.

Such evaluation standards as plumpness, roundness, force of cold upsetting, and the volume are made through the research on cold upsetting steel ball. Through a designed orthogonal test and the DEFORM simulation analysis, the process of ball billet is explained reasonably after primary selection and screening. Thus through comparison, it is seen that the original process is improved to a large degree.

An in vitro biomodel with mechanical properties similar to those of human soft tissues is useful to learn skills for clinical practice of medical doctors or dentists (for instance for suturing oral mucosa). Poly (vinyl alcohol) hydrogel (PVA-H) with good mechanical strength and low surface friction has potential for use in such a biomodel for surgical trainings. The friction properties of biomodels and medical devices are an important factor for reproducing the natural feel of human soft tissue. However, while the low surface friction of PVA-Hs is well known, the effects of PVA factors such as concentration, polymerization, and saponification on the friction properties have not been clarified. In this study, five kinds of PVA-H samples with different properties were prepared, and ball-on-disk friction tests were carried out using a stainless steel ball, the same material as that of a surgical scalpel blade. Furthermore, the contact areas between the PVA-H sample and the ball were evaluated by measurement of the contact radii. Results showed that the friction coefficients of various PVA-Hs varied despite their similar contact areas.

According to requirements of online steel ball surface defect inspection, the automatic detection method of spherical surface defect on the track has been posed. To ensure photographing of the whole steel ball surface, the six CCD video cameras are used in this system. To overcome steel ball surface reflection, the red LED light source is used, and then the real and clear images are got. The steel ball surface defect is recognized accurately by means of image recognition technology and image reconstruction technology etc. This method provides theoretical basis and technical support for ball defection and quality classification.

Detailed fretting wear phenomena are usually hidden between the two compact contact interfaces. Direct or in situ observation of fretting wear is supposed to obtain time-dependent damage information. In this paper, the torsional fretting wear tests of plymethyl methacrylate (PMMA) flat against AISI 52100 steel spheres had been investigated on an improved test rig, which provides the real-time in situ observation, friction vibration and noise measurements. The running behaviours (frictional kinetics characteristics), wear mechanisms, oxidative behaviours and debris behaviours of the torsional fretting contact interfaces in combination with the friction vibration analyses were analyzed in detail. The results of observation suggested that a slight damage could be found in the partial slip regime. And the spindle-like detachment occurred in the mixed fretting regime, which presented a radial pattern distribution in the wear scar. The friction lateral vibration decreased accompanied with the accumulation of the debris, and the appearance of third-bodies helped to reduce the friction vibration. In the mixed fretting regime and slip regime, the wear mechanisms mainly were fatigue wear and oxidative wear.

(n-octylic acid)-N-quinazolin-4-one methylester was synthesized as potential lubricating oil additive. The friction and wear behaviors of the synthesized compound as an additive in liquid paraffin on 12.7mm diameter steel ball bearing specimen were evaluated with a four-ball machine. The worn surfaces of the steel balls were observed using a scanning electron microscopy and X-ray photoelectron spectroscopy. It was found that the novel compound as an additive in liquid paraffin was effective in improving the tribological performance.

Cast steel joints have been widely utilized in large-span spatial structures. Based on Ordos airport terminals engineering, the structure and design method of ribbed steel ball nodes is put forward in this essay, in which nonlinear finite element method is applied, bearing capacity and deformation capacity of ribbed steel ball nodes in the complex stress state is made a penetrating analysis to determine mechanical performance of the ribbed steel ball. Among other things, the manufacturing process and technical standards of cast steel ball nodes are elaborated.

In this study, a direct observation of a point contact area was conducted to understand the scuffing phenomenon. The contact area was produced between a rotating sapphire disc and a stationary steel ball and it was lubricated using n-hexadecane. The image detected by a colour digital CCD camera, load, and friction were synchronously recorded by a computer during the test. It was found that wear debris produced in the contact area played an important role in the wear process, which includes running-in and scuffing. In the test, debris particles accumulated in the inlet zone, and some particles entered the contact area to cause abrasive wear of the ball surface, even in the light-load stages. During the running-in process, the abrasive wear by debris particles changed the conformity between the sliding surfaces. In the high-load stage, just before the occurrence of scuffing, the whole contact area was flattened at once. When scuffing occurred, the contact area suddenly expanded. The conformity of the contact area was dramatically changed during its expansion. The flattening of the whole contact area and dramatic expansion with changing the conformity seemed to play important roles in scuffing.

This article presents a study on the movement of an oil entrapment (or impact dimple) in a pure rolling elastohydrodynamic lubricated (EHL) contact. The oil entrapment was formed by impacting a steel ball against a lubricated glass disc. The contact was then activated under pure rolling conditions, and the movement of the entrapped oil was visualized by optical interferometry. It was found that during the movement of the dimple within the EHL contact, there exists a critical value for the displacement of dimple core. For the displacement of the dimple core less than the critical value, the dimple moves at the entrainment velocity and the film thickness of dimple core remains almost constant. For displacement beyond the critical value, the dimple slows down and its depth decreases rapidly. The effects of influential factors such as speed, initial dimple depth, load, and initial gap size were theoretically and experimentally investigated.

An experimental investigation of the lubricated steady-sliding contact for elastically soft solids is reported. We show that the anisotropic character of the surface roughness has a strong influence in determining the transition from boundary lubrication, where the normal load is fully supported by the asperity–asperity interactions, to the hydrodynamic regime, where a thin fluid layer completely separates solid surfaces from direct contact. In particular, tests have been carried out using a ball-on-flat test configuration to measure the friction coefficient at the contact between a smooth steel ball and a rough PDMS as a function of the sliding speed. The most noteworthy result is that the presence of roughness anisotropy strongly modifies the classical shape of the Stribeck curve as a consequence of local micro-EHL conditions which occur at the contact interface.

Lauric acid-N-quinazolin-4-one methylester was synthesized as potential lubricating oil additive. The friction and wear behaviors of the synthesized compound as an additive in liquid paraffin on 12.7mm diameter steel ball bearing specimen were evaluated with a four-ball machine. The worn surfaces of the steel balls were observed using a scanning electron microscopy and X-ray photoelectron spectroscopy. It was found that the novel compound as an additive in liquid paraffin was effective in improving the tribological performance.

Ball penetration test is used to measure the penetration depth of steel ball on the original asphalt pavement which is under impact load. The penetration depth is to evaluate the flexibility of the original pavement and one of mix proportion design parameters of chip seal. The test result is the plastic deformation of asphalt pavement under impact load. In this paper, layered half-space elastic-plastic model of the asphalt pavement is set up by transient dynamic analysis which is in structural analysis, the progress of the steel ball impacting pavement is numerical simulated, and the plastic deformation of asphalt pavement under impact load is studied. Results indicated that the using material parameters are mainly reasonable and the theoretical calculation result satisfies the requests of the engineering application. The method and results can be used in the theoretical analysis of chip seal mix proportion design.

Fracture of interim fixed partial dentures (FPD) is of important concern to the dental surgeon, especially with long-span fixed partial dentures or areas of heavy occlusal stress. Polymers used in interim FPDs, reinforced with glass fibers have shown to have a positive effect on the fracture resistance of interim FPDs. Since little research has been done on the influence of silane treated glass fibers on the fracture resistance of interim FPDs, this study was conducted to evaluate the effect of silane treatment of glass fibers on the fracture resistance of interim FPDs and its correlation with the position of fiber reinforcement and length of the span of the interim FPD. Interim FPDs were fabricated from an autopolymerizing polymethyl methacrylate (PMMA) resin. Seven FPDs were made in each group. The FPDs in the control group were unreinforced, and in the other groups the FPDs were reinforced either with non silane treated glass fiber or with silane treated glass fiber. The fibers were placed in two different locations in the FPDs. Three length of span of FPDs were tested. The load was applied to the FPD by a steel ball placed in the center of the pontic space. One Way Anova, Two Way Anova, Studentized range test (Scheffe's). Results showed that the load required for fracturing the unreinforced FPDs varied from 272 to 998 N. Mean fracture load of reinforced FPDs varied from 536 to 1642 N. One-way analysis of variance showed that the position of fibers and the silane treatment fibers significantly affected the fracture load. The results of this study suggested that the silane treatment of glass fibers had a marked improvement in the fracture resistance of FPDs as compared to untreated glass fibers. Selective placement of the glass fibers at the undersurface of the pontic and the occlusal surface of the interim fixed partial denture showed more increase in the fracture resistance as compared to the randomly distributed glass fibers. The glass fiber reinforcement is effective in increasing the fracture resistance with the effectiveness most evident in interim FPDs with long spans. With increase in the length of span of interim fixed partial denture the fracture resistance was shown to decrease significantly in all the groups.

BACKGROUND: Fibrinogen concentrate administration can be guided by measuring fibrinogen concentration or quality of the fibrin-based clot. This study compared different fibrinogen concentration measurement methods with maximum clot firmness (MCF) of the fibrin clot, assessed by thromboelastometry (FIBTEM), in 33 cardiovascular surgery patients receiving fibrinogen concentrate for hemostatic therapy. STUDY DESIGN AND METHODS: Blood samples were collected after cardiopulmonary bypass (CPB) and after fibrinogen concentrate administration. FIBTEM MCF was measured using a rotational thromboelastometry device (ROTEM, Tem International). Fibrinogen concentration was measured using photo-optical (CA-7000, Siemens Healthcare Diagnostics), mechanical (KC-10 steel ball, Schnitger and Gross hook, Amelung GmbH), and electromechanical (STA-R, Diagnostica Stago) coagulometers. Assessments included agreement between fibrinogen concentration measurements and correlations between fibrinogen concentration and FIBTEM MCF. RESULTS: After CPB, correlations were significant (p

In order to simply and accurately measure the realistic motion of balls in a ball bearing, a method called the static oblique coordinates is proposed to measure the 3D motion of balls in an angular contact ball bearing. This measuring method utilizes Hall elements as the sensors which are assembled on the side of outer race and cage of the ball bearing with magnetized balls. The voltage signals of the Hall sensors are collected online and applied to calculate and analyze the variation of magnetic axis of the magnetized ball, from which the 3D motion of the balls can be calculated. The basic principles and experiment method of the measuring method are illustrated. This method has simple structure without damaging the bearing, by which the bearing’s real motion can be studied consequently with a high precision. The magnetization and magnetic pole detection methods in this study effectively solved the problem of magnetized balls’ magnetism un-uniformity which causes the measure signal chaos.

According to the hot rolling technological requirements on the bearing-steel-ball blanks, an automated conveying system program was proposed. The primary structure and the characteristic of this automatic conveying system was introduced as well as the working principle of it. It was found that the system possessed the advantages such as higher feeding accuracy, good job stability and rational construction and it can meet the process requirements.

The paper studied on the balling-up mechanism of hard-grinding by focusing on the defects in the process of the hard-grinding of steel ball. In order to achieve better precision and efficiency in the process of producing steel ball, we improves the grinding wheel’s structure by increasing the rotation velocity of the ball and thereby improving the producing efficiency.

In response to the dilemma for image identification by the existing classifier toward surface defects of steel ball, an improved support vector machine (SVM) for multiclass problems is proposed. Minimum distance method is presented to resolve the unclassifiable region of the multiclass SVMs. The 16 image features of the surface defects are selected as input vector of the SVMs. The experiment results show that more accurate identification toward surface defects of steel ball was achieved by the improved multiclass SVM and the accuracy can reach 95%.

Advanced machining process telah terbukti dalam teknologi proses rekayasa untuk surface finishing dan proses material removal , atau dengan proses traditional finishing: fase fundamental, unrestrained, dan permintaan tinggi dalam fase tenaga kerja selama produksi. Finishing abrasif magnetik, pada polishing dalam proses non-konvensional mampu menyelesaikan dengan presisi dengan proses pemesinan yang dikontrol oleh medan magnet dan itu tidak berlaku untuk beberapa proses kompleks di mana teknik penyelesaian konvensional dapat dengan mudah diterapkan. Makalah ini mengulas teknik praktis untuk memoles bantalan AISI 316L ST Ball dengan proses finishing abrasif magnetik untuk menyelesaikan desain permukaan bola eksternal . Parameter input yang berbeda dari proses ditinjau seperti kecepatan elektromagnetik, arus dan tegangan langsung yang diinduksi, kepadatan fluks magnetik, jumlah ukuran partikel abrasif, lingkungan kerja , dan bahan benda kerja . Input yang terjadi untuk proses finishing bantalan bola stainless steel dapat memvalidasi kinerja laju material removal rate dan surface roughness.

Density is an inherent property of matter, which plays a very important role in production and life. There are many and relatively simple methods to measure the density of large particulate matter. But the density measurement of fine-grained solid materials is difficult because of the volume measurement. Existing methods require expensive and complex equipment. In order to measure the density of fine solids in a simple, convenient, accurate and rapid manner, This paper uses water to fill the gap between the particles of materials, and then through the conversion of water mass and volume, so as to calculate the volume of materials, so as to calculate the density of fine-grained materials. This paper takes fine-grained phosphate ore as an example to demonstrate the application method of this study. The density of phosphate ore measured by this method is 2.84g/cm³ cubed, which is consistent with the theory. Steel ball and copper chip are also used for verification, and the calculated density is close to the theoretical density, which verifies the accuracy and reliability of this method. Through research and demonstration, this method can make it easy, fast and accurate to measure the density of fine solids, save time and investment, and improve efficiency and efficiency.

Multiwalled carbon nanotubes (MWCNTs) were functionalized and were used as additives in paraffin oil to improve its lubrication effect for bismaleimide resin. The tribological behavior of bismaleimide resin lubricated by the paraffin oil filled with the functionalized carbon nanotubes was investigated by friction and wear tester. The wear surface of the resin with steel ball as tribopair was analyzed by means of scanning electron microscopy (SEM). It was found that the addition of this kind of functionalized MWCNTs effectively reduced the friction coefficient. An optimal additive concentration existed in the system and was found to be 0.025 wt%. A lubrication model for the resin and steel ball system was postulated and it was the isolating effect and bearing structure of f-MWCNTs that played a key role in friction and wear reduction.

Experimental results are presented on the rolling of a steel ball over a small step. The experiment was designed to simulate the effects of surface roughness on rolling motion, where collisions between asperities on the ball and the rolling surface act to enhance the coefficient of rolling friction. In the present experiment, the ball was launched as a projectile when colliding with the step, with a consequent increase in vertical speed and a decrease in horizontal speed. Results are presented for four different diameter balls and four different steps, at incident rolling speeds between 0.3 and 1.2 m s−1.

Si-doped diamond-like carbon (a-C:H:Si) films can be deposited at an ultra-high rate around 100 μm h−1 by using microwave sheath-voltage combination plasma (MVP), showing a friction coefficient of 0.05–0.1 similar to that of conventional a-C:H:Si films. However, the effect of humidity on the friction property of a-C:H:Si films deposited by MVP has not been studied. Thus, we investigate the frictional characteristics of a-C:H:Si films deposited on different duty ratios of 10, 30, and 50% using MVP, where a steel ball is slid against an a-C:H:Si film under dry conditions with 10%–50%RH. The a-C:H:Si film deposited on the low duty ratio of 10% became a polymeric structure. The friction coefficients of the a-C:H:Si films decreased with a decrease in the relative humidity. At the low relative humidity of 10%, it was shown that low friction below 0.06 is achieved by transfer film with the amorphous carbon structure formed on the mating ball.

In this study, the friction and wear properties of Fe 7 Mo 6 -based alloy, Fe and Mo disk specimens sliding against ASTM 52100 steel and Cu and SiC ball (or pin) specimens in ethyl alcohol were evaluated using an Optimol SRV oscillating friction and wear tester. The Fe 7 Mo 6 -based alloy disk specimens exhibited more stable friction coefficients than the Fe and Mo disk specimens when slid against the ASTM 52100 steel ball specimen. On the other hand, the Fe/SiC tribo-pairs exhibited the lowest average friction coefficients (0.14–0.17).

A single-axis ultrasonic levitator applied in containerless processing of materials was introduced. It could suspend steel ball with density of 7.9 g/cm3 as well as else material samples easily. The finite element model of singe-axis ultrasonic levitator was developed to study the incident acoustic fields. Three-dimensional distribution of time-averaged potential is focused and the results are successful to confirm some experimental phenomena such as the movement of sample along concave reflector and the deviation of object near the reflector.

The moduli of concrete has been determined by various testing methods. The impact resonance (IR) method has been shown to be truly a simple nondestructive testing method which produces consistent results. It is possible to determine not only the modulus but also damping ratio from the IR test. However, the values of elastic modulus and damping ratio of concrete from the test is known to be affected by various test conditions including, specimen support condition, impact steel ball size and sampling rate. In this study, the optimum IR test conditions are suggested and validated experimentally. The test results showed that the recommended test conditions yielded a variation of resonant frequency within ±0.3% and damping ratio ±10.0%. In addition, the modulus from the IR test was comparable to that from a static test when the effect of strain amplitude was properly taken into account.

A new passive vibration control strategy has been put forward and applied to a cantilever beam in this paper. For the beam under principal resonant harmonic excitations, a steel ball was inlaid in its interior closed cavity without any restricts, constructing an impact system. For the system, a spring-damping impact model was employed to simulate impacts between the beam and the steel ball, and dynamic governing equations ware derived. Numerical simulations show that the amplitude of the beam vibration response is significantly reduced by the impact damping of the steel ball, and moreover, the vibration response isn’t periodic but quasi-periodic due to impacts. The self-adaptive characteristic of the steel ball is fully demonstrated by assuming that the ball impacts the beam on a virtual location instead of the actual location observed in experiments. In general, all numerical results agree with those of experiments.

At very high speeds, elastohydrodynamic (EHD) films may be considerably thinner than is predicted by classical isothermal regression equations such as that due to Dowson and Hamrock. This may arise because of viscous dissipation, shear thinning, frictional heating or starvation. In this article, the contact between a steel ball and a glass disc over an entrainment speed ranging from 0.05 m s−1 to 20 m s−1 was studied. Two sets of tests were performed. In the preliminary testing, the disc was driven at speeds of up to 20 m s−1 and the ball was driven by tractive rolling against the disc, its speed being determined using a magnetic method. After all possible explanations for the reduction in film thickness at high speeds were considered, it was shown that the results, which fall well below classical predictions, are consistent with inlet shear heating at the observed sliding speeds. Another set of tests was then performed, with both disc and ball driven separately, so that the accuracy of the shear heating ...

In this paper, a surprising behaviour of the store security tag is elucidated. We explain why one can easily introduce a steel pin into the tag, while it is impossible to pull it out even if you use extremely great forces. Unexpectedly there is not any sophisticated device inside the tag, rather the whole job is done by a small steel ball placed in a simple, bucket-like container. The asymmetric behaviour of the pin follows from a specific positive feedback loop, enhancing the maximum value of static friction, that occurs only when one tries to draw the pin out of the tag.

Tribological properties of a nano-eutectic Fe1.87C0.13 alloy were investigated under distilled-water lubrication against AISI52100 steel ball for various applied loads and sliding speeds. For comparison, the tribological behavior of annealed coarse-grained Fe1.87C0.13 alloy was also examined under the same testing conditions. Worn surfaces of both alloys were analyzed by using a scanning electron microscope (SEM). The wear rate of nano-eutectic Fe1.87C0.13 alloy was on the order of 10−5 mm3/m. The wear rate of nano-eutectic Fe1.87C0.13 alloy was higher than that of annealed Fe1.87C0.13 alloy at lower load, but lower under higher load. The friction coefficients of the two alloys were similar and exhibited a slight increase with increasing sliding speed, but a small decrease with increasing applied load. The wear mechanism of the nano-eutectic Fe1.87C0.13 alloy was transformed from plowing and corrosion wear to slight fatigue cracking with increasing applied load, whereas that of the annealed coarse-grained Fe1.87C0.13 alloy was transformed from plowing and corrosion wear to severe fatigue flaking.

The tribological properties of the Langmuir-Blodgett poly-4-vinylpyridine monomolecular films and cationic polyelectrolytes: polydiallyldimethylammonium chloride, polyallylamine, and polyethyleneimine monolayers were studied. The highest stability toward the mechanical impact of a steel ball (indenter) was observed in the poly-4-vinylpyridine film formed at the surface pressure 20 mN m−1.

Objective To investigate the effect of indenter size on the failure mode of amalgam and its interaction with thickness. Methods Dental silver amalgam (Lojic+, SDI) discs, 10 mm diameter, thickness h = 0.4–8.0 mm, were stored in air at 37 °C for 7 days before testing in ‘Hertzian contact’, resting freely on a 30% glass fibre-reinforced nylon 6,6 substrate (E: 10 GPa) at 23 °C in air at a crosshead speed of 0.2 mm/min. The load at the first crack, detected acoustically, was recorded. Two series of tests were conducted. In the first, a 3 or 20 mm diameter hard steel ball was used to apply the load to discs with h = 0.4–8.0 mm. The second was performed on discs with h = 2.0 and 5.0 mm with indenter diameters D = 2–40 mm. Results The failure loads for these two groups were substantially different, with most values for D = 3 mm being lower than those for D = 20 mm. The transitions of the main failure mode with increasing thickness were similar, i.e., from RC-dominant for h small to CC-dominant for h large, except that this occurred over a greater range for the larger indenter. For h = 2 mm, failure load was constant for D = 2–40 mm; all specimens consistently failed from bottom RC. For h = 5 mm, failure load increased with D with a quadratic relationship up to about 10 mm (r2 = 0.85), after that, values were near constant; the failure mode gradually changed with D from PD- or CC-prevailing for D small (≤5 mm) to RC-prevailing for D very large (30 and 40 mm). Significance The failure mode of amalgam is dependant on the indenter size; indenter size and coating thickness have reciprocal effects.

The intrusion tests of a ball into sliding contact space were carried out. A stainless steel ball with 3.175 mm radius was used as a sphere particle to study the critical intrusion condition of the ball into the contact space between the organic glass and the polyurethane rubber. The effect of intrusion angle of the contact space and the friction coefficients among the ball, the organic glass and the polyurethane rubber on the critical condition were studied experimentally. Then, the intrusion conditions for the ball into the contact space were analysed theoretically. The results showed that the calculated critical intrusion angles agreed well with the experimental ones. Finally, the intrusion diagram as a function of critical intrusion angle, friction coefficient µ1 and µ2 (here, µ1 is the friction coefficient between the ball and the polyurethane rubber, µ2 is the friction coefficient between the ball and the organic glass) was introduced to evaluate the intrusion performance of a ball into the sliding contact space. Copyright © 2010 John Wiley & Sons, Ltd.

An experimental program was carried out to investigate the behaviour of slurry-infiltrated fibrous concrete (SIFCON) slabs under impact loading. Fibre-reinforced concrete (FRC), reinforced cement concrete (RCC) and plain cement concrete (PCC) slabs were also cast and tested for comparison purposes. The impact force was delivered with a steel ball drop weight. The test results revealed that SIFCON slabs with 12% fibre volume fraction exhibit excellent performance in strength and energy-absorption characteristics when compared with other slab specimens. Regression models have been developed to estimate the energy absorption for SIFCON slab specimens.

This study investigated the effect of a particle diameter and a weight fraction of RB ceramics particles on friction and wear of polyamide 66 composites filled with RB ceramics particles (PA66/RB ceramics composites) sliding against a bearing steel ball under dry condition. RB ceramics particles with a mean diameter of 3, 30, and 150 μm were used as the filler. Weight fractions of RB ceramics particles were 10, 30, and 50 mass% for the mean diameter of the particles of 3 μm, and 30, 50, and 70 mass% for the mean diameters of 30 and 150 μm. The smaller mean diameter and the higher weight fraction of RB ceramics particles provided lower friction coefficients and lower specific wear rates with the PA66/RB ceramics composites. The composite with a mean diameter and a weight fraction of RB ceramics particles of 30 μm and 70 mass% took the lowest friction coefficient of 0.27 among the composites. The composite with a mean diameter and a weight fraction of RB ceramics particles of 3 μm and 50 mass% took the lowest specific wear rate of 1.3 × 10-9mm2/N among the composites, which was equivalent to the specific wear rate of RB ceramics disk.

Through the analysis of the interaction form between steel balls and the material in Micro-level, the primary form in different areas confirmed and the requirement of ball grading presented. The different methods of ball grading and the different influence on the interaction between steel balls and the material clarified. At last, a clear description of the calculation method of the ball grading made through an example.

The rolling wear behavior of unfilled polyamide 6, polyoxymethylene and polyetheretherketone materials were investigated, using different wear testing rigs. In most of them, a steel ball rolls on the polymer plate surface in a rotational or linear motion. The results qualify the different polymers with regard to their resistance against rolling wear. The potential of various fillers and reinforcements for a possible improvement was also identified. But almost all showed an insufficient suitability when compared to the unfilled materials. Differences in wear mechanisms were illustrated by microscopic methods. But more works need to be done to understand all the interesting observations.

In the detection process of the ball detector, surface can not unfold effectively, which brings about that the camera can not capture the image which we want, resulting in a high rate of defect and at a low efficiency in the test with the ball detector. In order to solve this problem, the optimized design on the mechanical control parts of the expansion organization was carried out, besides, kinematics analysis model the expansion organization and a motor control timing schedule were created by ADAMS, enabling expansion process consistent with the mathematical modeling. To a certain extent the optimization results improve overall performance of the system, which plays a guiding role in the improvement of the system.