Wiper Blade Research Articles

Vibration response analysis of boneless wiper-windshield system based on multi-body dynamics model

The vibration and noise generated by the boneless wiper-windshield system during its actual operation bother the occupants. Exploring the dynamic characteristics of the boneless wiper-windshield system is a prerequisite for understanding vibration and noise. In this paper, the dynamic characteristics of the boneless wiper-windshield system are investigated, and a rigid-flexible coupled multi-body dynamic model matching the real boneless wiper-windshield system is constructed. The friction characteristic of the dynamic model is studied through the wiper test bench experiment. The nonlinear dynamic response of the dynamic model is calculated with the Adams and results of the frictional vibration are well reproduced in real motions. The parallel analysis of the simulation calculation results and the real vehicle test results confirms the validity of the model. The results show that the vibration generation mechanism at the moments before and after the reversal can be explained by the instability of the wiper blades due to the negative friction characteristic. There are differences in the magnitude of the reversal impact force and the moment of reversal at each position of the wiper blade. The effect of the speed-gears on the system vibration is analyzed through the simulation results. The analysis method and simulation results in this article can provide reference for the research on vibration and noise control of boneless wiper systems.

Contributions to the synthesis of the windshield wiper mechanism with one rocker-slider blade

The paper deals with synthesis of the windshield wiper mechanism with one rocker-slider blade. Starting from the kinematic scheme of the constructive model designed by Mercedes-Benz motor vehicle company, a structure analysis on this complex mechanism consisting of three kinematic chains, of which two are articulated bar mechanisms and one is planetary mechanism, has been accomplished. The novelty of this paper consists in the presentation of an optimum synthesis method of the planar bar mechanism in two variants for the wiper blade driving. The first variant is a planar 4-bar mechanism type crank-rocker where the cosines theorem has been applied in order to obtain the lengths of the coupler and the crank. The second analyzed variant is a bi-contour linkage consisting of two 4-bar mechanisms linked in series. Further, the calculation of the planetary gear angular velocity on the complex mechanism with dyadic kinematic chains has been achieved. In order to do this, the immobilization of the planetary carrier method has been applied. Finally, the geometry of the driven linkage of the wiper mechanism type crank-slider which has two mobilities has been studied. A vector equation has been written in order to obtain the length of the variable blade.

Determining the characteristics of contact interaction between the two-row windshield wiper and a curvilinear glass surface

Among the evaluation criteria for determining the efficiency of vehicle windshield cleaning, the pressure distribution of the wiper rubber brush on the glass surface is important. The problem is the lack of this indicator standardization by the United Nations Economic Commission for Europe Rules (UNECE) regarding the windshield wipers certification. The inhomogeneity of the pressure distribution of the conventional wiper (the object of research) is additionally due to the mobility of the links of its mechanism and the plasticity of the rubber brush together with the blade. The pressure value should not be more than 30–50 kPa (33.4 kPa was recorded for the immobilized wiper case), and the external normal load on the frame should be kept within 20...30 N. Under a load of 24 N, the wiper blade was deformed by 1.48 mm (according to R43, it cannot exceed 1.5 mm). Further loading of the wiper frame causes two types of plastic deformation: local and global (loss of the rubber brush shape). Local displacements have increased to 1.82 mm, and the shape of the blade has acquired a "sliced" character, which causes thin jets of dirt. Global ones led to the rubber brush bending with the gap between it and the glass (5.7 mm) and caused the blind zone appearance. Models to mathematically predict layer-by-layer deformations of a conventional wiper were investigated. A model of a double-row blade with separate brushes was built, which enables the parallelization of water flows and explains the increase in the efficiency of its design. Hydrodynamic tests showed 1.58 times greater effectiveness compared to a classic single-row blade: the water flow rate was 15.61 vs 9.86 m/s. This technological advancement is the subject of a patent and a possible working prototype

The influence of contact distribution shaping on the dynamic response of a wiper blade

The primary function of windscreen wipers is to remove water and debris from the windscreen, ensuring the driver has a clear view of the road ahead. Predicting wiper performance at the design stage is therefore important to ensure their safe operation. There is hence a need to develop physics-based models of wiper performance that can be used as evaluative tools early in the design stage. This paper presents an analysis of the impact of changing screen curvature on the contact force distribution of a wiper blade and the subsequent effects on the transient dynamics. The contact distributions for three distinct screen curvatures and three loading points are calculated via FEA (finite element analysis) and subsequently analysed via multiple connected mass spring dampers to model the wiper blade lip transient dynamics. By analysing time and frequency domain data for several calculated contact distributions it is found that decreasing the screen curvature reduces the contact force at the centre of the blade, however, increases the amplitude of vibrations and range of frequencies observed. Additionally, it is found that moving the loading point towards the tip of the blade reduces the amplitude of vibrations, a result analogous to that of increasing the screen curvature. Based upon the understanding gained through this work the influence of design criteria on wiper blades can now be assessed, and several suggestions made as to how to reduce windscreen wiper noise.

Utilization of Laparoscopic Choledochoscopy During Bile Duct Exploration and Evaluation of the Wiper Blade Maneuver for Transcystic Intrahepatic Access.

This study aims to examine the indications, techniques, and outcomes of choledochoscopy during laparoscopic bile duct exploration and evaluate the results of the wiper blade maneuver (WBM) for transcystic intrahepatic choledochoscopy. Choledochoscopy has traditionally been integral to bile duct explorations. However, laparoscopic era studies have reported wide variations in choledochoscopy availability and use, particularly with the increasing role of transcystic exploration. The indications, techniques, and operative and postoperative data on choledochoscopy collected prospectively during transcystic and choledo- chotomy explorations were analyzed. The success rates of the WBM were evaluated for the 3 mm and 5 mm choledochoscopes. Of 935 choledochoscopies, 4 were performed during laparoscopic cholecystectomies and 931 during 1320 bile duct explorations (70.5%); 486 transcystic choledochoscopies (52%) and 445 through choledochotomies (48%). Transcystic choledochoscopy was utilized more often than blind exploration (55.7%% vs 44.3%) in patients with emergency admissions, jaundice, dilated bile ducts on preoperative imaging, wide cystic ducts, and large, numerous or impacted bile duct stones. Intrahepatic choledochoscopy was successful in 70% using the 3 mm scope and 81% with the 5 mm scope. Choledochoscopy was necessary in all 124 explorations for impacted stones. Twenty retained stones (2.1%) were encountered but no choledochoscopy related complications. Choledochoscopy should always be performed during a chol- edochotomy, particularly with multiple and intrahepatic stones, reducing the incidence of retained stones. Transcystic choledochoscopy was utilized in over 50% of explorations, increasing their rate of success. When attempted, the transcystic WBM achieves intrahepatic access in 70%-80%. It should be part of the training curriculum.

Simulation and experimental analysis on frictional vibration in the reversal process of a wiper-windscreen system

This paper studies the frictional vibration aspects of the automobile wiper-windscreen contact system and builds a numerical model that matches the test equipment. The reversal vibration of the contact system is examined by the dynamics part of a theoretical model with the derived analytical formulas. The fluid lubrication characteristics are investigated by the friction part of the model with solutions of the friction coefficient-negative slope formula for relative velocity and the friction coefficient formula in the time domain. The nonlinear dynamic response of the theoretical model of the wiper blade is calculated with the Runge-Kutta method and the results of the frictional vibration are well reproduced in real motions. The validity of the model is confirmed by parallel analyses of the simulated results and the experimental ones of the wiper-windscreen system. It is concluded that properly reducing the length of blade tip is an effective way to reduce vibrations of the system. The influences of the wiping speed and acceleration after reversal on the system vibrations are also analyzed through experimental investigations. The theoretical and experimental results presented in this paper can be reference to structural optimization of the wiper blade and vibration and noise control of the wiper-windscreen contact system.

Optimized Wiper Design using Computational Fluid Dynamics

This paper presents the robust use of Computational Fluid Dynamics (CFD) techniques as complement to wind tunnel testing for the performance assessment of rain water and wiper wash behavior on windscreen surfaces. The objective of this paper is to predict windscreen wiper design performance and its effectiveness with the help of CFD. Clear visibility to the occupants is the key for stress free and safer driving experience, therefore it is important to study the windscreen wiper system performance under different work load conditions. A multi-phase CFD code is used to simulate rain drops and its impingent on the vehicle is modeled with the help of thin liquid film. The wiper blade motion is defined with inputs from multi body dynamics (MBD) considering the driver and passenger side wiper blade speed and extent. Time-dependent results for the wiper blade location, water fluid film spread, and its height on the windscreen, A-pillar, leaf-screen rain gutters were obtained. The CFD results then equated with the physical test data. The calculated water film pattern found to be associated with the observed patterns of the waterways on the test vehicle. Multiple design studies were performed on the CFD model which are also reliable with similar test configurations. From the results, it is concluded that numerical simulation of water behavior on vehicle surfaces is possible, and CFD method is effective tool to assist engineers in envisaging, analyzing, and designing water management systems. A Computational Fluid Dynamics code had been introduced in order to simulate the cleaning performance of the automobile wash. Multi-phase thin film with rigid body motion models were used for this purpose. The objectives of the project were to quantify the water flow, enhance visualization, and develop a CAE methodology which will assist in the product development process.

Dynamic characteristics and generation mechanism of windscreen frameless wiper blade oscillations

Dynamic characteristics and generation mechanism of windscreen frameless wiper blade oscillations

Dynamic Analysis of a Wiper Blade in Consideration of Attack Angle and Clarification of the Jumping Phenomenon

Automobile windshields are typically curved, creating an oblique angle of attack between the wiper blade and the windshield. This attack angle means that the wiper may jump off the windshield while wiping, causing a chattering noise and preventing the rainwater from being fully wiped off the windshield. Thus, it is important to examine the dynamics of the wiper blade under friction. In this study, the relationship between the attack angle and the jumping phenomenon is clarified through dynamic analysis. We introduce an analytical two-link model corresponding to an actual wiper blade that considers the exchange of dynamic and static friction between the windshield and the blade. The dynamic friction is assumed to be negatively correlated with the relative velocity, and the static friction is described by a set-valued function. As the motion transitions from the stick state to the slip state, the equation to be solved changes. Hence, the initial condition after a transition must agree with the final condition before the transition. Because the governing equations are nonlinear and the solution is highly dependent on the initial condition, the transition time and corresponding state variables are vital. The slack variable method is used to obtain the exact transition time and initial conditions. The sign of the normal force acting on the blade from the windshield determines the occurrence of the jump phenomenon. A larger attack angle makes the jump phenomenon more likely. However, the jump phenomenon does not occur when the motion of the blade reverses. Experimental observations support the theoretical description of the wiper blade.

A theoretical analysis of friction and vibration characteristics of wiper reversal process

This paper is concerned with the friction and vibration characteristics of a vehicle wiper-windscreen contact. The dynamics and friction models of the wiper-windscreen system are established to study the frictional vibration and noise of the wiper-windscreen system. The dynamic model of the wiper-windscreen system is established and the analytical formulas are derived. Based on the negative slope formula of friction coefficient with respect to relative velocity, the Coulomb’s friction law, and the fluid lubrication characteristics, the friction models of the system are built in dry and wet operating conditions, respectively. Meanwhile, the formulas of friction coefficient and relative velocity in time domain are presented. The changes of blade angle and friction with time in different working conditions are investigated. The Runge-Kutta method is used to analyze the nonlinear dynamic response and friction characteristics of the friction models. The simulations successfully reproduce the vibrations of the wiper blade in actual motion. The effectiveness of the dynamic model and the friction models is verified by comparing the simulation results under different working conditions. The dynamics and friction models presented in this paper can provide theoretical references for structural optimization of the wiper blade, and thereby the vibration and noise control of the wiper-windscreen system.

Improving the mechanical properties of natural rubber composite with carbon black (N220) as filler

Abstract Rubber is one of the most commonly employed materials in the whole world. Earlier rubber obtained from natural resources was widely used. However, as industries grew tremendously, many new products were introduced to the world and rubber can be used for almost all the practical applications including as windshield wiper blade in automobiles. Most of the windshield wiper blade are made of synthetic rubber. Our research is focused to replace the synthetic compounds in wiper blade with natural materials which will be durable and eco-friendly. Natural rubber, treated with Carbon black (N220) as fillers and Silica in the presence of vulcanizing agents and other organic additives, works much more efficiently. Sulphur was replaced with Xanthate and soybean oil was used instead of petroleum products during vulcanization. The mechanical properties were investigated by various composition of Carbon black (N220) and silica. The tension test, abrasion test, and wear test were studied for different five compositions.

Geometric Analysis of the Vibration of Rubber Wiper Blade

The purpose of this paper is to work out the theoretical aspects of the vibration problem of rubber wiper blade on convex windshield. Over the past 20 years, some $2$-dimensional spring-mass models were presented in engineering science to simulate the vibration of rubber wiper blade on windshield. In this paper, we will consider the elasticity perspective on this $3$-dimensional vibration problem. Our theoretical analysis suggests that there should exist two classes of vibration frequencies corresponding to “$\ast$-exact deformations (Class I)” and “$\ast$-closed deformations (Class II)”. We prove mathematical theorems on the characterization of deformations of Class I. We also explain how elementary deformations of Class II can be constructed. We then deduce two mathematical formulas, for the vibration problem of rubber wiper blade on convex windshield, from our theoretical analysis. Our theoretical predictions are in almost perfect agreement with experimental data. One of the crucial steps of our analysis is a decomposition theorem motivated by the de Rham Cohomology and the Hodge Theory.

Analysis of the Cross-Sectional Shape and Wiping Angle of a Wiper Blade

Analysis of the Cross-Sectional Shape and Wiping Angle of a Wiper Blade

Study to enhance the mechanical properties of natural rubber by using the carbon black (N550)

Natural rubber is one of the important material in the manufacturing industry with applications varying from footwear to an aircraft industries. An investigation was conducted on the nature of material so as to increase its effectiveness in its function in cleaning off water, dust and other impediments of the windscreen of automobiles. A research has been conducted on various compositions of rubber by adding various fillers to improve the properties. The main objective of this work is to enhance the mechanical properties of the natural rubber used in the windshield wiper blade using Carbon black (N550) in two different compositions. Abrasion test, hardness test, tensile and tear tests were conducted on the specimen.

Dynamic Behaviour and Characteristics of Rubber Blade Car Performance

High technologies have helped so much in improving an optimizing the engine design and performance of the car. Improved isolation has helped to minimize the engine noise making other automotive part noises become more detectable. One of the noise sources are the wipers. When a wiper operates on a windshield, vibratory phenomena may appear due to flutter instabilities and may generate squeal noise. In order to obtain good wiping behaviour and characteristics, the rubber blade should be in complete contact with the glass and under uniform contact pressure while not generating vibration as it moves over the glass. A good wiping performance can be achieved by a proper design of the wiper structure as well as a good understanding of the mechanical behaviour of the rubber blade. The primary objective of this research is to investigate the dynamic behaviour and characteristics of rubber wiper blade performance in order to reduce the automotive windscreen wiper noise and vibration effects. In order to achieve the objective of this research, two types of wiper is used. One is hybrid type and second is conventional type. Then the behavior of wiper can be investigated. The force resistive sensor is used to measure the force distribution exerted on the windshield for the characteristics wiper noise for specific points. The obtain vibration data is processed by single-board microcontrollers. Behaviour movements of blade produce different vibration that can be investigated the maximum noise occurs on wiper blade operation using Uni-axial accelerometer A MMA7660. As a result, confirmation behaviour is shown the contact force distribution between rubber blade and glass is produce non-uniformly contact force and identical for hybrid type wiper and uniform contact force and not identical for conventional type wiper. In addition, characteristic of wiper rubber blade due to environment condition such as humidity, temperature and wiper stiffness are major factor in this research. As a conclusion, the results for behaviour of wiper blade depends on structural effect of the wiper blade related to the contact force distribution between the rubber blade and the glass. Secondly the characteristics of wiper rubber blade depends environment condition such as humidity and the temperature. The methodology is achievable to discovery the knowledge of dynamic behaviour and characteristics of wiper rubber blade in future.

Healing of Planar Defects in 2D Materials via Grain Boundary Sliding.

Understanding the mechanisms and kinetics of defect annihilations, particularly at the atomic scale, is important for the preparation of high-quality crystals for realizing the full potential of 2D transition metal dichalcogenides (TMDCs) in electronics and quantum photonics. Herein, by performing in situ annealing experiments in an atomic resolution scanning transmission electron microscope, it is found that stacking faults and rotational disorders in multilayered 2D crystals can be healed by grain boundary (GB) sliding, which works like a "wiper blade" to correct all metastable phases into thermodynamically stable phases along its trace. The driving force for GB sliding is the gain in interlayer binding energy as the more stable phase grows at the expanse of the metastable ones. Density functional theory calculations show that the correction of 2D stacking faults is triggered by the ejection of Mo atoms in mirror twin boundaries, followed by the collective migrations of 1D GB. The study highlights the role of the often-neglected interlayer interactions for defect repair in 2D materials and shows that exploiting these interactions has significant potential for obtaining large-scale defect-free 2D films.

Wiping Simulation of Wiper Blade Considering Piecewise Linear Stiffness and Stick-Slip Phenomenon

Wiping Simulation of Wiper Blade Considering Piecewise Linear Stiffness and Stick-Slip Phenomenon

Basic Performances and Research Trends in Wiper Blade Rubber

Basic Performances and Research Trends in Wiper Blade Rubber

Novel compliant wiper mechanism

Abstract. Conventional wiper mechanisms that are used in automotive vehicles comprise numerous linkages and joints. In this study, in order to obtain a simpler design, a novel compliant wiper mechanism is introduced. The wiper mechanism is essentially a partially compliant four-bar mechanism. To the best of our knowledge, this is the first compliant wiper mechanism in the literature. The wipers currently labeled “compliant” in the literature possess only a flexible wiper blade frame. However, these are still driven by conventional rigid body mechanisms. After introduction of the fundamental concept, a compliant wiper mechanism is designed for an L7e car. Finite element analysis is carried out for verifying analytical results and fatigue calculations are performed. Finally, a prototype is manufactured, and it is experimentally verified that a compliant wiper mechanism may have an infinite life.

Contact Force and Dynamic Behavior of Automobile Wiper Blade System

Windscreen wiper vibration problem is now becoming one of the comforts and safety concerns because it can be annoying to the driver and passengers and also affect concentration of the driver while driving. This paper investigate the problems by measuring the wiper blade contact force and vibration level on laboratory wiper experimental rig and wiper system on two different sedan passenger cars operated similarly. In order to measure the vibration and contact force along the wiper blade, MMA7660 accelerometer and a thin film force sensor FSR was used. The contact force is measured at four points; Points 1 (inner tip), 2 (middle blade) and 3 (middle blade) and Point 4 (outer tip), along the wiper blade. Based on the measurement, it was found that the contact force is much higher at Points 1, Point 2 and Point 3 compared to Point 4. For vibration level, higher vibration is occurred at Points 2 and Point 3. It can be conclude that the bigger the contact force value act on windscreen the bigger for the vibration level to be produce. From this founding, further research can be conducted and tackle the problem at certain point along the wiper blade.