Bicycle Frame Research Articles

Bicycle Frame Prediction Techniques with Fuzzy Logic Method

Bicycle Frame Prediction Techniques with Fuzzy Logic Method

Day 1. Posters – Sport and Performance

Background: Exercise tests are one of the most commonly used tools within sports science research. Therefore, the reliability of such exercise tests is of critical importance when investigating the efficacy of nutritional, physiological, psychological or training interventions. Purpose: The aim of this experiment was to measure the reliability of a 20 km cycling time trial performance test when performed by mounting the cyclists own bicycle frame on an electronic turbo trainer. Methods: Twenty one male cyclists (age 35 ± 8 y, height 1.82 ± 0.05 m, body mass 80.7 ± 9.0 kg) completed the 20 km time trial on three separate occasions; the initial visit was a habituation trial and was followed by two main trials. All laboratory visits were conducted at the same time of day, following a 24h diet and activity standardisation period, and at least 2 h postprandial. The time trial was completed on a Cyclus2 (RBM Electronic, Germany) ergometer. The cyclists mounted their own bike frames on to the ergometer and the settings on the Cyclus2 were adjusted for each individual bike, ensuring an accurate measurement of distance and performance. During the exercise trial, participants were deprived of any performance information other than distance covered and gear selection; no encouragement was provided by experimenters. Results: There was no order effect of the trials, inclusive of the habituation trial (p = 0.901). There was no significant difference in the time taken to complete the 20 km between trials 1 and 2 (trial 1: 1969 ± 112 s; trial 2: 1975 ± 119 s; p = 0.222). The intra-class correlation between trial 1 and 2 was r = 0.99, with the coefficient of variation being 0.7%. Conclusions: The use of a 20 km cycling time trial, in which the cyclists bicycle frame is mounted on a cycle ergometer, is highly reproducible. Such a test can, therefore, be reliably used to detect changes in performance due to various interventions.

PENGEMBANGAN KONSEP SEPEDA PERKOTAAN DENGAN MEMPERTIMBANGKAN KRITERIA ERGONOMI

The development of the Indonesian urban bicycle concept requires the most suitable bicycle type as the initial reference which is decided by considering various criteria. Ergonomics is one of the important criteria, considering that the high frequency riding bike which bring health risks, such as CTS, kyphosis and urogenital disorders. Short wheel base recumbent bike is the most potential for development. The development of this bike includes increased balance by reducing the length of the bike frame and tubing, improve handling by replacing the handlebar is comfortable and uses smaller tires, and use kickstand for easy parking. Besides, the development of this bike adapted to the Indonesian anthropometry and features that support the ability of this bike to explore the city streets. Keywords:urban bikes, ergonomics, development, short wheel base recumbent bike

Age-Hardening of Rheo-High Pressure Die Cast Al-Alloy 6066

Al-Mg-Si-Cu alloy 6066 is a heat-treatable wrought alloy that is commonly used in high performance bicycle frames. Wrought alloys are difficult to cast using conventional liquid casting techniques, as hot tearing can occur. However, a method that effectively reduces that risk is rheo-high pressure die casting (R-HPDC). Casting alloy 6066 using semi-solid metal processing makes it possible to be used for near-net shape forming of components. This study investigates the age-hardening response of R-HPDC alloy 6066. The effects of different solution heat treatments, natural pre-ageing and artificial ageing are studied. The different solution heat treatments investigated are a one-step and a two-step solution treatment. The one-step treatment was performed at 530°C only and the two-step treatment at 530°C followed by 550°C. It is shown that natural pre-ageing has a detrimental effect on the T6 properties and that the longer two-step solution heat treatment is justified due to an increase in hardness and prevention of incipient melting. The Vickers hardness in different temper conditions (F, T4, T5 and T6) were determined and compared to the typical hardness values of the alloy in the wrought condition.

Development of a multi-directional rating test method for bicycle frame stiffness

The methods for determining the bicycle frame stiffness exist in many forms. Because the stiffness measuring method is not standardized, each bicycle magazine or bicycle constructer uses his own test configuration. This leads to a wide variety of setups; they differ in many aspects such as applied load, boundary conditions and frame deflection measurement. To clarify some shortcomings in frame testing, a multi-directional rating test method for bicycle frame stiffness has been developed. The proposed test rig design considers different aspects that should be taken into account when measuring the bicycle frame stiffness.At first, it is important to eliminate perturbing side effects that influence the stiffness value of the bicycle frame. FE analysis revealed that using ‘very stiff’ boundary conditions to constrain certain degrees of freedom should be handled with the utmost caution. Using these non-rigid boundary conditions affects the bicycle frame deflection significantly. Therefore, prior to stiffness testing, the contribution of the test rig compliance should be estimated. It is advised to limit its estimated influence below 2 %. Hysteresis effects due to stick-slip and friction are avoided by omitting fixed boundary conditions and eliminating the friction force when using a pulley mechanism; if not errors up to 11 % are observed. It is recommended to use a rolling contact to constrain translation motion and to measure the force acting on the frame without other mechanisms between the force sensor and the bicycle frame. Another issue is the effect of the head tube bearing type and the preloading torque. The industrial bearings reduce the frame stiffness up to 19 % when comparing with steel bearing replicas. It is the operator’s decision to test bicycle frames with or without industrial bearings for stiffness measurements. Though, steel bearings are advised for mutual frame comparison since this avoids discussion about the differences among industrial bearings. The overall accuracy of the test result is expressed as percentage deviation on the 95 % confidence interval and includes both the influence of the operator and the sensors. To detect small changes between results from different frames, a percentage value of 2 % or less is desired.The selection of stiffness configurations is based on the major load components acting at the head tube, the bottom bracket and the rear-dropout. The bracket- and torsion stiffness are replaced with a specific classification of the test setup. The directional frame stiffness is as such assessed for individual load cases: (i) the in-plane vertical and horizontal stiffness of the bottom-bracket and rear-dropout, (ii) the transversal or out-of-plane stiffness of the bottom bracket and (iii) the torsion stiffness with or without the contribution of the rear-triangle of the bicycle frame. As such is detailed information available for the bicycle constructor to modify the design and for the cyclist when comparing the stiffness characteristics of different frame types.

The role of conspicuity in preventing bicycle crashes involving a motor vehicle.

Background: Bicycle use, despite its proven health and other benefits, is rarely part of everyday travel for many people due to the perceived risk of injury from collision crashes. This article investigated the role of physical vs. attention conspicuity in preventing bicycle crashes involving a motor vehicle in New Zealand. Methods: The Taupo Bicycle Study involved 2590 adult cyclists recruited in 2006 (43.1% response rate) and followed for bicycle crash outcomes through linkage to four national databases. A composite measure of physical conspicuity was created using latent class analysis based on the use of fluorescent colours, lights and reflective materials, and the main colour of top, helmet and bike frame. Attention conspicuity was assessed based on regional differences in travel patterns and the amount of riding in a bunch. Cox regression modelling for repeated events was performed with multivariate adjustments. Results: During a median follow-up period of 6.4 years, 162 participants experienced 187 bicycle–motor vehicle crashes. The crash risk was not predicted by the four latent classes identified and the amount of bunch riding but was higher in Auckland, the region with the lowest level of bicycle use relative to car use. In subgroup analyses, compared to other latent classes, the most physically conspicuous group had a higher risk in Auckland but a lower risk in other regions. Conclusion: Conspicuity aids may not be effective in preventing bicycle–motor vehicle crashes in New Zealand, particularly in Auckland, where attention conspicuity is low.

Optimal strength design of composite bicycle wheels

A high specific strength and specific stiffness are essential in high-performance bicycle wheel design. However, it is challenging for traditional materials to satisfy these trends, although advanced composite materials can be selected to simultaneously satisfy those requirements. This paper presents ply stacking sequence optimization for a composite bicycle wheel subjected to standard loading cases. In the design of a high performance composite bicycle wheel, the stacking sequence of composite plies in the wheel is an important parameter. The objective function for the optimization is to minimize the Tsai-Wu failure index. For optimal design, finite element analysis is conducted for a composite rim. Discrete ply-angle stacking sequence optimization was used for the development of a composite bicycle frame. The amount of change in the discrete ply orientation was 15°, and the limits of design variables were −180°<θ< 180°. The optimal stacking sequences to minimize the maximum failure index were determined, and the possible failure regions under different loading conditions were predicted. Numerical results showed that this algorithm can be effectively used for lay-up optimization of composite wheels.

Gross efficiency is improved in standing position with an increase of the power output

Background: Gross efficiency (GE) has been shown to be one of the most relevant parameter influencing cycling performance but to the best of our knowledge, just one study focused on measuring GE in seated and standing positions during field conditions (Millet et al., 2002: Medicine & Science in Sports & Exercise, 34(10), 1645-52). Other authors investigated the effects of change in body position (seated vs. standing) on energy expenditure, heart rate (HR) or pulmonary ventilation (VE) but there were large changes in the results (Ryschon & Stray-Gundersen, 1991: Medicine & Science in Sports & Exercise, 23, 949-953; Swain & Wilcox, 1992: Medicine & Science in Sports & Exercise, 24, 1123-1127) due to the different protocols. Indeed, the cross effect of slope and intensity on GE in standing compared to seated position has not been studied. Thus, we found interesting to measure GE in real locomotion with elite cyclists at different intensities and slopes. Purpose: This study was designed to examine the effects of standing position on GE compared to seated position at different intensities and slopes. Methods: After a period of familiarisation, 13 elite participants performed on a motorised treadmill with their own bike one session during which they rode in a randomized order seated vs. standing positions with several slopes (5, 7.5 and 10%) and intensities (3.8, 4.2 and 4.6 W.kg-1). GE was calculated for each condition using the ratio of power output (PO) measured with a Powertap G3 hub (CycleOps, Madison, USA) and the oxygen uptake (VO2) measured with a portable gas analyzer (Metamax 3B, Cortex, Leipzig, Germany). Results: GE was significantly higher (+4.5%) in standing position (21.5 ± 5.2 %, CV = 5.2%) compared to seated position (20.6 ± 1.1 %, CV = 5.5%) for all the intensities and slopes. This improvement was due to a significant (p < 0.001) increase of PO in standing position (+4.5%) associated with a stabilization of VO2. The more the slope was low and the intensity was high, the more the pedaling cadence was high. That leads to higher PO changes between standing and seated positions (R = 0.93, p < 0.001) (Figure 1). Discussion: The main finding of this study shows that in standing position, GE was increased from a higher PO. The non-significant increase in VO2 is in accordance with the previous results of Millet et al. (2002). It's the first time that a study shows an increase in PO in standing position. The difference in PO is linked to an increase of the pedaling cadence. We hypothesize that the increase in PO is due to the technique adopted in standing position, the latter has an impact on the mechanical deformation both of the tires and the bike frame. The loss of energy in the bike and the tires would require to increase the PO in standing position according to the technique of each cyclist. Conclusion: Despite a significant decrease of GE, the standing position involves a significant increase in PO probably due to an increase of the deformation of both the tires and the bike frame according to the pedaling techniques of the cyclist.

Application of Product Line Commonality Index (PCI) in a Family of Products

Currently many companies base their marketing strategy around a family of products. Thus, they regularly add new variations to products in order to meet changing market needs, or to attract new customers. Although the basic functionality remains unchanged across products, new features, aesthetic appearance and technologies are incorporated in each new product. This if it is not checked, can generate the “complexity of the product,” which leads to a loss of productivity or quality. Thus, the effective management of product variations in design and manufacturing is challenging. The key is minimizing the non-value added variations through models within a range of options without limiting customers. This article discusses the factors that contribute to the "complexity of the product” and this is done through the product line commonality index (PCI) , which measures the level of common parts in a product family. A case study of bicycle frame displays its implementation and functionality. The index shows the possibility that the products in a family share parts effectively (modularity) and reduces the total number of parts (multifunctionality).

Uniform Design and Dynamic Finite Element Analysis for Permanent Deformation Improvement of an On-Road Bicycle Frame Undergoing the Drop-Mass Impact Test

The purpose of this paper is to present the use of uniform design of experiments method and dynamic finite element analysis in improving the permanent deformation of an on-road bicycle frame which undergoes the drop-mass impact test. Firstly, four dimensional parameters of the bicycle frame are selected as the control factors to be improved. Then, uniform design method is used to construct a set of experiments. Each experiment denotes a specific design of frame. Next, for each experiment, the dynamic finite element analysis package ANSYS/LS-DYNA is employed to simulate the behavior of bicycle frame which undergoes the drop-mass impact test and determine the permanent deformation of the frame. Lastly, the best frame of all the experiments which causes the smallest permanent deformation is selected as the improved version of design. Compared with the original design which causes a permanent deformation of 8.458 mm, the improved version causes a permanent deformation of 7.467 mm. The rate of improvement is 11.7 %.

The Automatic Calculation of Cumulative Lamination and Analysis of the Structural Static Rigidity of Bike Frame Made of Carbon Fiber Composite

This paper discusses the process of calculating the lay-up configuration and structural stiffness of carbon fiber composite bike frame. First, a program is written in ANSYS macro language to calculate the lay-up configuration of the composite. The user only has to input the geometry, fiber orientation and sequence of individual layer, according to the original shop drawing. The program will then calculate the lay-up configuration of all the details for the whole structure automatically, and create the finite element model for ANSYS. The stiffness is then analyzed according to the product specification, and also compared with test result to evaluate the validation of the model. This automated process can accelerate the development time frame, and also work as the basis of parametric model for future design optimization.

Some ideas on the inspection of aluminium mountain bicycle frames

Some ideas on the inspection of aluminium mountain bicycle frames

다양한 형상비를 갖는 사각 CFRP 튜브의 굽힘 및 비틀림 특성

ABSTRACT: Fiber reinforced composite materials have outstanding specific strength and specific stiffness. So the useof composite materials increases in various kinds of industrial fields including sports goods such as bicycles.Composite materials are used to make structural parts with various kinds of shapes. Specially, rectangular compositetubes are used to make a few of composite bicycle frames, but there has been a few of research on this issue.Rectangular composite tubes are designed to have appropriate radius of curvature and endure bending and torsionalloads. In this research, nine kinds of rectangular composite tubes having aspect ratios 1:1, 1:1.5, 1:2 and radius ofcurvatures R5, R10, R15 were fabricated. The carbon fiber reinforced composite material was used to make tubeshaving same cross sectional areas. The stacking sequence of tubes is [0/90/±45]s. Experimental evaluation wasaccomplished to apply bending and torsional load to the tubes. Experimental results show that bending and torsionalcharacteristics depend on radius of curvature and aspect ratio of rectangular composite tubes.초록

Additional material feeding method by plunger shape design for hydroforming of triangular tubes

In this study, a hydroforming process is used for the manufacture of a bicycle frame tube, one side end of which is expanded to an acute-angled triangular shape from the initial tube, which has a regular triangular cross section. The end section of the expanding side is designed to be smoothly connected with the initial tube cross section to maintain sealing by the plunger. The tube hydroforming process is controlled using an axial feeding plunger and a pressure intensifier. Various load conditions can be applied to the initial tubes through these units. However, the experimental results showed that forming into the desired shape without bursting at the expanding area or shear cracking at other areas was not possible. These problems seem to occur because the circumferential propagation of plastic deformation is constrained by the triangular cross-sectional profile of the initial tube. To resolve this problem, less axial feeding should be supplied to the compressing zone compared with the expanding zone even in a single tube. In this work, besides conventional axial feeding, an additional axial feeding method by an end cam–shaped plunger is suggested to supply different axial feeding for each circumferential location of the tube. Finite element simulation and experimental studies are performed to verify the effectiveness of the concept.

3D printing the world's first metal bicycle frame

Renishaw, which makes metal additive manufacturing machines in the UK, has collaborated with a British bicycle company to create the world's first 3D printed metal bike frame. Liz Nickels spoke to the company to find out what the process involved.

Framebuilder entrepreneurship

The handmade bicycle industry has grown exponentially over the past decade. Although existing for decades in much smaller numbers, the popularity and credibility of framebuilder entrepreneurship–custom, handmade bike frames–has increased significantly in the past 10 years. The companies that specialize in custom-producing bicycle frames vary in size, scope, reputation, profitability, and even building materials.

자전거 프레임 포크에서의 진동 해석

This study investigates structural and vibration analyses for three types of bike frame fork models. As long as the maximum equivalent stresses of these models are lower than the yield stress, the three models are considered to be safe structurally. Type 3, with a maximum equivalent stress of 169.23 MPa, has the lowest stress among the three models and the strongest strength. Types 1, 2 and 3 have natural frequencies lower than 270 Hz. Type 3, with a critical frequency of 118 Hz, has the best durability under vibration among the three models. In order to decrease the vibration transmitted to a bike rider riding on a rough road, the impact due to vibration can be relieved by selecting a Type 3 model from among the three models. The results of this study can be effectively utilized for the design of a bike frame fork as this allows the anticipation and prevention of damage caused by durability issues.

Design of Multi Gender Bicycle - As an Alternative Bike Design to Fulfill Appropriate Requirement for Urban Society in Indonesia

In the present work, a multi-gender bike, which can be used by men and women, was designed. The integrated design method is used to develop a bicycle frame. As a human transportation the frame is must be light, strong, and comfortable for rider. The frame of bicycle is built with the material of aluminum alloy T-6061 and is produced as prototype for a multi gender purpose. With 100 kg load the strength of material is calculated, and the result shows that the frame critical strength is smaller than material ultimate strength. The prototype was tested by 5 respondents who have an average weight of 68.2 kg, and height 169.4 cm. Pedal test is conducted with 5 level of speed such as 6, 8, 10, 12, and 14 mph in 6 minutes of cycling respectively. The paddle energy during cycling was determined. The results show that the paddle energy increase and follow the increasing of speed. However since 10 mph of speed the paddle energy tends to be fixed with average value of 40 kcal. Therefore the tension leg muscles before and after cycling is going together by increasing the speed. The RULA method is used for determining the ergonomic of multi-gender bicycle, and the result shows that the value of risk injury is 3, that mean the developed bike is ergonomic.

Bike Braking Vibration Modelling and Measurement

Modern bicycle disk-brake systems often induce vibration and noise in bike components such as brake rotors, wheels, and even bike frames. When the vibration or noise are excessive, brake performance can be perceived as unsatisfactory. Previous research incorporating bike frame structural dynamics and brake friction modeling has shown that stick-slip friction is likely the cause of much of this vibration and noise. Bicycle design parameters such as brake friction behavior and bike component structural properties are central in producing and/or sustaining these vibrations. The predicted dynamics of these models has correlated reasonably well with the testing of braking systems. This research extends the modelling of previous efforts to improve correspondence with brake noise/vibration testing and gain further understanding into the contributors and possible cures of this unwanted vibration. Specifically, the extended model incorporates torsional wheel dynamics (including rotor/hub, rim, and tire inertias, and spoke, rotor, and tire stiffnesses) into previous models. This new model allows the dynamics of the bike frame and wheel to couple through braking application. To support and validate the modelling, motion/vibration measurements are recorded during noisy braking with a non-contact laser vibrometer in the laboratory and with an accelerometer in field tests. Vibration measurements are studied along with model predictions toward the goal of connecting unwanted noise/vibration with specific design parameters of the bicycle brake-frame-wheel system.

Customized CAD System Design Based on GMDH Method for Racing Bikes

A set of customized CAD application system based on GMDH method for racing bike frame is developed by summarizing the characteristics of man-machine engineering principle and bike sports, taking self-organizing data mining method of using Group Method of Data Handling (GMDH) as well as AutoCAD as platform. The system with functions of customized design of bike, parametric design drawing and rapid automatic modeling improves the design level and efficiency of bike frame.