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Electrospinning is a low-cost and straightforward method for producing various types of polymers in micro/nanofiber form. Among the various types of polymers, electrospun piezoelectric polymers have many potential applications. In this study, a new type of functional microfiber composed of poly(γ-benzyl-α,L-glutamate) (PBLG) and poly(vinylidene fluoride) (PVDF) with significantly enhanced electromechanical properties has been reported. Recently reported electrospun PBLG fibers exhibit polarity along the axial direction, while electrospun PVDF fibers have the highest net dipole moment in the transverse direction. Hence, a combination of PBLG and PVDF as a core–shell structure has been investigated in the present work. On polarization under a high voltage, enhancement in the net dipole moment in each material and the intramolecular conformation was observed. The piezoelectric coefficient of the electrospun PBLG/PVDF core–shell fibers was measured to be up to 68 pC N−1 (d33), and the voltage generation under longitudinal extension was 400 mVpp (peak-to-peak) at a frequency of 60 Hz, which is better than that of the electrospun homopolymer fibers. Such new types of functional materials can be used in various applications, such as sensors, actuators, smart materials, implantable biosensors, biomedical engineering devices, and energy harvesting devices.

Shear thickening fluid polishing (STFP) is one type of the non-Newtonian fluids which is used to polish the complex shapes. This method is applied to machine the spherical hardened steel in this study. The principle and performance of STFP was introduced. There are many parameters that significantly influence the STFP process; however, the inclination angle of the workpieces is one of the parameters that greatly affect the pressure distribution and deviation of surface roughness at different area on the workpiece surfaces. The effect of inclination angle, fluid viscosity, and polishing speed to the machining process is carried out by simulating. The inclination angle parameters of the workpieces such as 0°, 3°, 5°, 7°, 10°, 12°, and 15° are used during the simulation and experimental process. The distributed pressure area and polishing fluid flow characteristics will be presented and analyzed. Simulation results show that the inclination angle of 5° and fluid viscosity of 3 Pa.s are the best combination. The pressure area is distributed throughout all the surface of the spherical steel and maximum pressure value is achieved about 9.29 Pa in the case of 5° inclination angle. In addition, experimental results illustrated that the surface roughness achieved is the smallest when inclination angle of 5°, the fluid viscosity of 3 Pa.s, and polishing speed of 100 rpm. The best surface roughness can be reach 12 nm after 15 min polishing. The deviation of surface roughness is about 14 nm in this case. This result agrees well with simulation results. The simulation and experimental results show that STFP was a promising and feasible processing method in the polishing of workpieces with complex shape.

Recently, microwave-assisted drying is an emerging drying technique that can help to accelerate the water removal process. In this paper, a microwave-assisted experimental drying study of carrot slides is presented. A microwave-assisted heat pump dryer is fabricated where the drying agent temperature, the supplied microwave power, and the circulative fan speed are easy to adjust. A series of 61 drying experiments is conducted with a range of drying temperature from 35 °C to 45 °C, a range of microwave power from 0 to 1.25 W/gram, and air velocity varied from 0.55 m/s to 1.70 m/s. The drying kinetics of the dehydration process is analyzed. Based on the obtained result, suitable intensive drying conditions for carrot slices are proposed. To extend the applicability of the experimental study, an artificial neural network (ANN) model of the drying process is developed. Instead of estimating the network for individual drying conditions in previous studies, the network is established for the entire range of drying conditions. The results indicate that the proposed ANN model predicts the microwave-assisted drying process adequately.

The objective of this study is to experimentally examine the effect of applied load and surface texture on friction of UHMWPE in total joint replacement by measuring the coefficient of friction (COF) between CoCrMo pin and UHMWPE discs. A CoCrMo pin with the dimensions of 11 mm in diameter and 18 mm in length was machined to obtain the surface roughness of 0.25 µm. For preparing different surface texture, ten UHMWPE discs with the dimensions of 88 mm in diameter and 5 mm in thickness were machined by two different machining processes of milling and turning to obtain two roughness values of 2.5 and 0.25 µm. 25 mg/ml BSA was made by mixing BSA powder in 10% PBS. A frictional testing apparatus was developed and carried out for the calculation of COF. Results show that the COF increases with the increase of the applied load in both cases of the UHMWPE roughness of 0.25 and 2.5 µm. With the UHMWPE roughness of 0.25 µm, the COF decreases when the surface texture machined by milling compared to that by turning in both cases of the applied loads of 4 and 16 N; however, with the UHMWPE roughness of 2.5 µm, the COF increases when the surface textures machined by milling compared to that by turning. These results suggest that both the applied loads and the surface textures have important effects on the friction of UHMWPE.

The study aims to determine the effect of polishing parameters as well as polishing speed, abrasive sizes and electric current on surface roughness of titan alloy in the magnetorheological polishing (MRP) methods. When the electric field is applied, the rheological properties of MRP fluid will be changed in the machining process. As a result, the viscosity and shear yield stress of MRP fluid was greatly improved under applied electric current. The workpiece surface can be polished by the abrasive particles with adhering to MR fluid. The influence of polishing parameters on the surface roughness was investigated by experiments. The experimental results indicated that the polishing speed has a great influence on the surface roughness of workpiece. With the increase of the polishing speed, the best surface roughness can be obtained by using the MRP method. The abrasive size had very little effect on surface quality improvement when it was changed in the experimental process. In addition, the electric current also has a strong effect on the surface quality of workpiece. As a result, the surface roughness of ball titan alloy workpiece (O32 mm) was reduced rapidly from Ra = 120 nm to Ra = 18 nm under the appropriate machining conditions.

The surface quality and accuracy of the geometry of the cylindrical rollers are important factors for bearing life. This paper presents effects of machining parameters on the surface roughness, topography and roundness of cylindrical rollers through the lapping and polishing experiments. And then the surface roughness of the cylindrical rollers is optimized. The results found that the surface roughness of rollers is significantly changed in lapping process with different abrasive particle sizes, while the surface roughness has slightly reduced in polishing process. It also indicated that the smoother surfaces with better roughness can be obtained after lapping and polishing process. In addition, the surface roughness of cylindrical rollers is rapidly reduced from Ra of 0.5 µm to Ra of 0.063 µm after the 3-h lapping process and Ra of 0.013 µm after the 1-h polishing process. The surface topography of rollers can be achieved by the smoother surface when loads are from 25 to 35 N in lapping process, and the loads are from 35 to 40 N in polishing process. Finally, the Taguchi method is applied to optimize the surface roughness in polishing process. The result found that the optimal surface roughness achieves 0.015 µm with respect to the time of 35 min and type of 4000# Al2O3.

A large working travel and a minimal stress are the most critical characteristics of a microgripper but they are conflicted each other. This paper develops a new efficient hybrid algorithm to solve the multi-objective optimization design for a sand bubbler crab-inspired compliant microgripper. The structure of sand bubbler crab-inspired compliant microgripper is inspired from the profile of sand bubbler crab. A surrogate-assisted multi-objective optimization is conducted by developing a hybrid approach of finite element analysis, response surface method, Kigring metamodel and multi-objective genetic algorithm. First, the data are collected by integrating the finite element analysis and response surface method. Subsequently, in the types of common surrogates, Kigring metamodel is adopted as an efficient tool to approximate the objective functions. And then, the Pareto-optimal fronts are found via the multi-objective genetic algorithm. The results indicated that the optimal results are at the displacement of 5999.9 µm and stress of 330.68 MPa. The results revealed that the optimized results are highly consistent with both the validation results. The accuracy of the surrogate models showed that the regression model is a good prediction. The proposed approach is useful tool to solve complex optimization designs.

Introduction Standardized protocols are provided for maintenance and replacement fluid therapy in critically ill patients. However, unintended fluid sources (analgesics, antibiotics and other drugs) are not always taken into account when prescribing intravenous fluid therapy. We evaluated the extent to which maintenance, resuscitation and unintended fluids contributed to total fluid load in elective coronary artery bypass graft patients during their ICU stay. Methods Data on intravenous and oral fluid input and output were retrospectively collected from the electronic medical files. Results Sixty patients were included. Maintenance fluids represented 1435 ± 570mL (49%) and 2214 ± 657mL (71%), resuscitation fluids 847 ± 542mL (29%) and 338 ± 559mL (11%), unintended fluids 639 ± 162mL (22%) and 576 ± 285mL (18%) respectively on day 1 and day 2. Mean oral intake increased almost fourfold (from 258mL to 1017mL) on the second day. Conclusion Postoperative maintenance and resuscitation fluids are responsible for most of the observed total fluid load on the first two days after elective coronary artery bypass graft surgery. Unintended fluid load is underestimated and has to be taken into account during fluid prescription.

Modeling for robotic joints is actually complex and may lead to wrong Pareto-optimal solutions. Hence, this paper develops a new hybrid approach for multiobjective optimization design of a flexure elbow joint. The joint is designed for the upper-limb assistive device for physically disable people. The optimization problem considers three design variables and two objective functions. An efficient hybrid optimization approach of central composite design (CDD), finite element method (FEM), Kigring metamodel, and multiobjective genetic algorithm (MOGA) is developed. The CDD is used to establish the number of numerical experiments. The FEM is developed to retrieve the strain energy and the reaction torque of joint. And then, the Kigring metamodel is used as a black-box to find the pseudoobjective functions. Based on pseudoobjective functions, the MOGA is applied to find the optimal solutions. Traditionally, an evolutionary optimization algorithm can only find one Pareto front. However, the proposed approach can generate 6 Pareto-optimal solutions, as near optimal candidates, which provides a good decision-maker. Based on the user’s real-work problem, one of the best optimal solutions is chosen. The results found that the optimal strain energy is about 0.0033 mJ and the optimal torque is approximately 588.94 Nm. Analysis of variance is performed to identify the significant contribution of design variables. The sensitivity analysis is then carried out to determine the effect degree of each parameter on the responses. The predictions are in a good agreement with validations. It confirms that the proposed hybrid optimization approach has an effectiveness to solve for complex optimization problems.

This chapter deals with fracture mechanics of composites reinforced with short carbon and glass fibers. A short carbon fiber-reinforced polyamide 66 (SCFR-PA66) with 20 wt% fibers is introduced firstly. Then, dynamic fracture properties of the short glass fiber-reinforced polyamide 66 with 30 wt% of fibers (SGFR-PA66) are discussed. The influences of moisture on the fracture behavior of these materials are investigated through experimental studies. The impact properties of specimens are analyzed using a Charpy impact instrument. The fracture tests in the edgewise position of specimens are performed using Standard ISO 179. The results indicated that the moisture greatly affects the dynamic energy release rate of both materials. SGFR-PA66 has a higher dynamic energy release rate than SCFR-PA66. In addition, the dynamic energy release rate of both materials can be achieved at the same value when the moisture exceeds 2.4%. Finally, the fracture mechanism of SCFR-PA66 was investigated and analyzed. The energy release rate GIC of SCFR-PA66 was calculated to determine and predict the fracture properties of the material for the unidirectional short fiber composite.

The bearings have been applied in many industrial fields, such as mechanical engineering, electric motors, automation, cars, and motorcycles. It can work effectively under heavy load conditions [1–3]. Traditionally, the roller’s surface was fabricated by CNC turning and grinded finishing [4]. This machining process requires a large amount of time to achieve the required surface quality. Besides, the manufacturing environments such as force, velocity, accuracy, and vibrations of the machine greatly affect the efficiency of the conventional cylindrical roller fabrication process. Therefore, the manufacturing cost will be increased, and production yield will be low.

The non-Newtonian fluid polishing is an advanced method that is applied to machining the complex surfaces. This method significantly improves the surface quality and mechanical properties of the material. In addition, it also reduces the concentrated stress at the root of the gear, so the fatigue resistance of the material is increased. The characteristics of shear thickening fluid are applied to machining the alloy steel SCM435 gears in this study. Firstly, the relationships between main machining parameters (distance D, velocity V, and inclination angle I) and responses (pressure and surface roughness of gear) is investigated in the polishing process. The effect of three machining parameters to the polishing process is carried out by conducting the simulation and experiment. The simulations results found that the pressure area is distributed throughout all the gear surfaces and maximum pressure value is achieved about 16.3 kPa with inclination angle of 26 degrees. In addition, experimental results indicated that the surface roughness of the gear surfaces can be reach 12 nm after 25 min polishing. Finally, the multi-responses optimization is utilized to optimize the pressures on the gear surfaces in machining process. The experimental results illustrated that the surface roughness is achieved the smallest at maximum pressure area. The best surface roughness of the gear surfaces can be reach 13 nm under optimal machining parameters such as the distance of 15 mm, velocity of 1.5 m/s and inclination angle of 32 degrees.

The elastic deformation machining method is suitable for fabricating aspheric surfaces that have excellent physical properties of elastic materials. The machining process is carried out with the deformation model without mold. When vacuum pressure is supplied to the workpiece, the top surfaces of workpiece are deformed into aspheric shape. After machining process, the bottom surface will be formed into the aspheric shape and the top surface returns to its original flat surface form due to internal force and bending moments of the material. However, the accuracy will decrease due to the reduced thickness while the vacuum pressure keeps unchanged during machining process. Therefore, it is necessary to carry out the finite element analysis (FEA) to determine the vacuum pressure with corresponding to the reduced thickness. In addition, the mold with its surface approximates and the desired surface form of the lens is also presented. When uniform vacuum pressure is supplied to the workpiece through small holes of the mold, the workpiece will be deformed into aspheric profile as similar to the mold surfaces. In order to improving the form accuracy, the FEA and the experiment are studied for modifying the mold profile to correspond with bending strength of workpiece material.

The source transducers for parametric array (PA) sound are required to radiate the primary wave with high intensity and directivity so as to generate nonlinear interactions between strong acoustic waves at different frequencies effectively, resulting in so-called PA sound. Thickness-mode piezoelectric transducers using 1–3 lead zirconate titanate (PZT) polymer composites were used to produce wide-bandwidth PA sound due to their ability to generate high-intensity, high-frequency sound beams over a relatively wide frequency band. The small mechanical quality factor of 1–3 PZT polymer composites results in high damping of the polymer matrix leading to a transducer with relatively flat frequency response but yet decreased-power efficiency. A PZT polymer composite that can enhance the power efficiency of a PA source transducer over a wide frequency bandwidth was proposed. This is achieved by adopting thinner polymer matrix layers and PZT rods with dual resonance frequencies. A transducer demonstrated ultrasonic sound up to 197 and 203 dB (re = 1 μP) at 98 and 135 kHz, respectively. The power efficiencies were 50% at 98 kHz and 33% at 135 kHz. PA sound was successfully generated up to 150 dB (re = 1 μP) at 30 kHz with a half-power beam width of 3.4°.

The Ti-6Al-4V alloy is known as materials with high hardness and good mechanical properties. However, the machining process of this material faces many difficulties due to unfavorable machining conditions. When the machining parameters are not selected in accordance with the Ti-6Al-4V alloy, the surface quality of workpieces does not meet technical requirements. Therefore, the appropriate machining parameters are needed to upgrade the surface roughness of workpieces in high-speed machining (HSM) conditions. The main cutting forces Py and Pz, and surface roughness Rz during turning of Ti-6Al-4V alloy in HSM were investigated and evaluated in this study. The response surface method (RSM) was used to conduct experiments and establish the models of Rz, Py, and Pz under various cutting conditions of feed rate ([Formula: see text]), tool nose radius ([Formula: see text]), and approach angle ([Formula: see text]). As a result, the [Formula: see text] value has the largest impact on the Pz. Moreover, the machining parameters such as [Formula: see text], [Formula: see text], and [Formula: see text] have a great influence on the Py. The magnitude of Rz is mainly affected by [Formula: see text] value. Based on the optimal parameters, the average value of the force Pz has decreased from 238[Formula: see text]N to 169[Formula: see text]N, corresponding reduction of about 29%. The value of the force Py has reduced from 184[Formula: see text]N to 118[Formula: see text]N, corresponding reduction of about 36%. In addition, the surface roughness of the workpiece has been improved significantly from Rz of 5.6[Formula: see text][Formula: see text]m to 2.7[Formula: see text][Formula: see text]m under optimal parameters condition. The surface roughness of the workpiece after processing in high speed machining was reduced of 52% compared with cutting under non-optimal parameters condition. The best surface quality and minimum cutting force could be achieved under optimal processing parameters in high speed cutting method.

Elastic deformation machining method is a simple machining method in manufacturing aspheric surfaces process. In this method, the top surface of workpieces will deform and be in contact with the mold surface once vacuum is applied, while the bottom of workpiece is polished to flatness with the vacuum pressure is maintained stability. The machining process is finished when the thickness of workpiece is polished to size as required. When the vacuum is turned off and the workpiece is released from the mold, the bottom surface of the workpiece will be shaped into the aspheric surface as the top surface returns to its original flat surface form due to material elasticity. During machining, the form accuracy of aspheric surface is dependent on the value of vacuum pressure and contact between workpiece and mold surface. Therefore, the study of behavior of the glass in contact with the mold surface is necessary to determine the suitable mold surface. In this paper, the simulation results of the glass in contact with the mold in the different pressure values have been carried out. Based on the simulation and experiment results, the appropriate pressure values and mold surface are established for machining process by elastic deformation machining method. In order to improve the precision of form surface produced in elastic deformation machining, the mold profile is modified by selecting the finite element analysis results of workpiece in the case of vacuum pressure P = −95 kPa and the conic constant K = −3.

The study aims to examine the effect of surface roughness as well as lubricant and normal load on frictional response of CoCrMo-on-UHMWPE bearing using a custom friction-measuring device. A cylindrical CoCrMo pin with surface roughness of 0.25 µm was prepared. Ten UHMWPE discs with different surface roughness of 2.5 and 0.25 µm were machined. BSA at concentration of 25 mg/ml was prepared by dissolving in PBS. A custom pin-on-disc friction-measuring device was designed to measure the coefficient of friction (µ). The normal loads were varied in two values of 4 and 16 N at sliding velocity of 28 mm/s. The mean µ values were taken in 3600 s. Results demonstrated that BSA 25 mg/ml improved the frictional properties between CoCrMo-on-UHMWPE bearing (p < 0.0001) and the µ values were increase with the increase of the surface roughness as well as with the increase of the normal loads (p < 0.0001). These results suggest that BSA plays an important role in improving the lubricating ability of CoCrMo-on-UHMWPE bearing and the frictional response between CoCrMo-on-UHMWPE depend on the surface roughness as well as the normal load.

Electrospinning is a simple and versatile method to fabricate microfibers and nanofibers composed of various materials, such as polymers melts and their solutions. A great challenge in electrospinning is the positioning controllability of fiber deposition on a substrate. This paper describes a simple yet effective method to fabricate well-aligned electrospun fibers that are deposited accurately across a large target. A cylindrical collector rotating at high speed was used to collect the deposited fibers; two curved-dielectric films were installed at a distance of 1 mm from the collector to redirect the air flow generated by the motion of the collector and to intensify the electrostatic field at desired area having the width of several hundred micros to several millimeters. Several types of polymer solutions with different behaviors in electrospinning were used to verify the proposed method. The simulation results of the electrical field revealed that the electrical field intensified at the desired positions on the collector. The experimental results showed significant improvements in both the alignment and positioning controllability of electrospun fibers compared with conventional electrospinning with a rotating cylindrical collector. This method can improve the capability of electrospinning processes in fabricating structures composed of aligned micro/nanofibers to amplify a specific characteristic, such as piezoelectricity.

As a newly developed aspheric machining technology, elastic deformation molding process (EDMP) can convert complex aspheric surface machining to simple flat surface machining and has been successfully applied to aspheric surface machining. But during the machining process, workpiece made of brittle materials sometimes fractured, which seriously affected the reliability of the new machining method. In this paper, fragment analysis of fractured workpiece and finite element analysis of thermal stress have been carried out. Water leakage was observed during machining process which caused a high temperature difference inside workpiece, and the corresponding maximum thermal stress was up to 7 MPa near the boundary of contact area. Considering the tensile stress caused by elastic deformation in attaching process, the total tensile stress on attached surface of workpiece has exceeded the admissive bending strength of workpiece material which caused random fracture. Sealing measures like the use of silicone rubber sealant can effectively improve the stability of elastic deformation molding process.

The non-Newtonian fluid is one type of shear thickening fluid which applied to process the complicated products. In this study, the new method of shear thickening fluid polishing (STFP) was used to polish the alloy steel SCM435 gears and the principle and performance of polishing process were also introduced. In the polishing process, the inclination angle of gears was believed to be an important parameter that affects the pressure and surface quality at different position on the tooth surfaces because it determines the contact between the polishing fluid and the tooth surface of the gear. The influence of the inclination angles on the pressure distribution and characteristics of fluid flow was performed by simulation process. The inclination angles of 0, 4, 8, 12, 16, 20 and 24 degrees were chosen in this study. As a result, the best inclination angle of gears is about 16 degree in the machining process. The tooth surfaces of gear have been in contact with the polishing fluid and the produced pressure reaches of 14.88 kPa. In addition, the influence of polishing speed on pressure were carried out in this study when inclination angle was established about 16 degree. The produced pressure on tooth surfaces increased with increasing the polishing speed. The results indicated that the different polishing speed also greatly affects the surface quality and machining efficiency. Therefore, the suggested machining method can become a suitable processing method for polishing the complicated products.

The pathogenesis of delirium in critically ill patients is multifactorial. How hypotension and hypoxemia affect brain function and whether they can promote delirium remains unclear. A high cumulative positive fluid balance may also have a negative effect on brain function and promote delirium. We hypothesized that delirium would be more likely to develop in patients with low systemic arterial pressure, hypoxemia and a higher positive fluid balance, and investigated these associations in a prospective observational cohort study in patients with shock. After initial resuscitation, episodes of hypotension, defined as a mean arterial pressure (MAP), SCOPUS: ar.j, info:eu-repo/semantics/published

The elastic deformation machining method has been demonstrated to be a novel optical manufacturing approach which can greatly reduce and simplify the production of large aspheric lens. Upon completion of the machining process, the workpiece under process will be shaped into a desired surface form of mold. The method allows the lapping and polishing of aspheric optical surfaces using a large lapping or polishing tools. The subject of this study is to determine the surface shape of the finished glass workpiece after the lapping process of the elastic deformation machining process associated with molding. The experimental and finite element analysis (FEA) results were compared with the shape of the molded surface form. The form accuracy between the optical glass and mold is within 1.6 μm (within radius 32 mm). The conclusions show that the method proposed is effective for machining the aspheric optical glass with proper elastic deformation machining parameters.

BACKGROUND: To investigate if serum S100B protein levels could early detect cerebral complications under treatment extracorporeal membrane oxygenation (ECMO). METHODS: Serum S100B levels were measured over 5 days in 32 patients with cardiogenic and septic shock, including 15 patients who treated by ECMO and 17 who did not. Cerebral complications included hemorrhage, stroke, encephalopathy with myoclonus, and brain death. Delirium was identified by the positive Confusion Assessment Method in the ICU. RESULTS: S100B levels were elevated in 24/32 patients (75 %) at ICU admission. Five patients developed cerebral complications (2 hemorrhages with 1 brain death, 1 encephalopathy with myoclonus in the ECMO group and 2 strokes in the non-ECMO group). At day 5, S100B levels were higher in the 5 patients with cerebral complications than in the 27 without cerebral complications, regardless of ECMO (0.426 [0.421, 0.652] vs. 0.102 [0.085, 0.135] ?g/L, p = 0.011). S100B levels were also more elevated in 3 patients with than in 12 without cerebral complications associated with ECMO (0.799 [0.325, 0.965] vs. 0.102 [0.09, 0.607] ?g/L, p = 0.033). S100B levels were not associated with delirium after sedation withdrawal. CONCLUSIONS: Measurement serum S100B could be useful to detect cerebral complications in deeply sedated patients associated with ECMO but not for monitoring delirium after sedation withdrawal.

Elastic deformation machining is a fabrication method that exploits the elastic deformation properties of materials under stress. Coupled with plane lapping machining process, this new fabrication method is suitable for machining complex aspheric surfaces. Upon completion of the machining process, the workpiece under process will be shaped into a desired surface form. The elastic deformation machining has several advantages over traditional fabrication methods, i.e., high machining compatibility and high fidelity of material property during machining process. The subject of this study is to determine the surface shape of the finished glass workpiece after the lapping process of the elastic deformation machining. The experimental results were compared with theoretical calculations. In the case when the vacuum pressure is 50 kPa, the maximum deviation value between the deformation curves from the theoretical calculation and the experiment results is within 62 μm. In order to improve the precision of form surface, the vacuum pressure is modified from 50 to 42 kPa. This reduction corresponds to a change of workpiece thickness when it is lapped. The results of the change of vacuum pressure show that the form accuracy produced is improved significantly and agrees very well with theoretical calculations. The maximum deviation in this case is 1.6 μm. The study indicates that the experimental plane lapping setup that exploits the material elasticity property can be utilized to fabricate aspheric lenses with axisymmetric surface and low complexity.

Deformation behavior; Aspheric surface; Finite element method; Contact area Abstract. Elastic deformation machining is a novel processing method for aspheric surface. In the machining process, the workpiece will deform and be in contact with the molded surface once load is applied. In this paper, a finite element model was built with Abaqus/CAE package to predict the deformation behavior of glass plate and some significative conclusions were obtained. The numerical simulation results show that the contact area between the plate and the mold is increasing with different pressure. Once the required pressure value is determined exactly, the glass plate can be deform and completely contact with the mold. The deformed shape of glass plate will completely contact with the mold at pressure p=100kPa. These conclusions have the positive significance for the applying of elastic deformation machining.

Elastic deformation machining is a new developing machining method for machining aspheric optical workpieces. Fracture property of glass plate under uniform pressure has important influence on the design of mould which is the key part of elastic deformation machining. In this study, to explore the fracture property of glass plate under uniform pressure, the deformation property of glass plate under uniform pressure is analyzed, a fracture experiment of glass plate using vacuum absorption is carried out on a self-developed “fracture testing system” and the values of critical vacuum degree is fit to Weibull distribution. Results show that fracture of glass plate under uniform pressure is comminuted, and for glass plate with depth of 1.95mm and diameter of 96mm, the relative safe value of maximum center offset of the mould’s profile is 0.5mm.

Plane lapping method using the elasticity of materials has many advantages comparing with current machining method for aspherical surface machining. Due to the deformation of the workpiece, the material removal characteristics of this method are different from the traditional lapping process of flat surface. In this paper, based on the Preston equation and plate theory, the theoretical model of the material remove rate is built in the case of proving experiment. Then the proving experiment of elastic deformation method is carried out, the recorded values fit well with theoretical ones, which shows that the theoretical model of material removal property is valid and the variation of MRR is related to the deformed profile of workpiece.

As the consumer market in the optics, electronics and aerospace industries grows, the demand of ultra-precision aspheric surface increases. The shape accuracy of the optical lens changes significantly with deformation conditions and optical properties of the lens varies with stress distribution within the lens. Therefore, determining the deflection and stress of glass lens is very important to improve the quality of the lens. In this paper, the deflection and stress theoretical results of BK7 glass plate have been presented in different cases of elastic deformation processing. The results are compared with the finite element analysis (FEA) to demonstrate the robustness and accuracy of algorithm in calculation of stress and deflection. The mentioned finite element models were established using the software Abaqus/CAE. The analytical and FEA results showed that if the edge of plate is simply supported, the maximum deflection is 4 times larger than in the fixed edge case. Otherwise if the edge and centre point of plate is simply supported, the maximum deflection is 2.5 times lower than in the fixed edge case and 11.3 times lower than in the simply supported at edge case.