Which parts of the bike are prone to failure and what are the failure modes

The common vulnerable parts of the bicycle and their failure modes are as follows:

1.Chain: The chain will be gradually stretched during use, and when the chain is stretched to a certain extent, it will cause the chain to slack and affect the normal use of the bicycle. At this time, the chain needs to be replaced in time to ensure the normal operation of the bicycle.

2.Tires: Tires are subject to wear during use, and when tires are worn to a certain extent, it will affect the ride smoothness of the bike. At this time, the tires need to be replaced in time to ensure the normal use of the bicycle.

3.Brake line: The brake cable will be subjected to tension during use, and when the brake line is stretched to a certain extent, it will cause the brake to fail. At this time, the brake line needs to be replaced in time to ensure the safe use of the bicycle.

4.Steering mechanism: The steering mechanism will be subject to wear during use, and when the steering mechanism is worn to a certain extent, it will lead to inflexible steering. At this time, the steering mechanism needs to be replaced in time to ensure the normal use of the bicycle.

5.Foot pedal: The foot pedal will be subject to wear and tear during use, and when the foot pedal is worn to a certain extent, it will cause the foot pedal to loosen. At this time, the foot pedal needs to be replaced in time to ensure the normal use of the bicycle.

6.Bottom bracket: The bottom bracket will be subject to wear during use, and when the bottom bracket is worn to a certain extent, it will lead to the loosening of the bottom bracket. At this time, the bottom bracket needs to be replaced in time to ensure the normal use of the bicycle.

7.Flywheel: The flywheel is subject to wear and tear during use, and when the flywheel is worn to a certain extent, it will cause the flywheel to loosen. At this time, the flywheel needs to be replaced in time to ensure the normal use of the bicycle.

In short, the bicycle will be affected by various factors during use, and it is easy to fail the above parts. During use, it should be checked and maintained in time to ensure the safe use of the bicycle.

Strength failure is a failure caused by insufficient strength, such as the fracture of mild steel when it is under tension. Stiffness failure refers to the plastic deformation or vibration of the structure that continues to bear or is in normal use, and the simple understanding is that the deformation of the structure exceeds the required value, such as the beam does not meet the requirements of the allowable deflection. Stability instability in material mechanics mainly refers to the bending and deformation of slender compression rods and the loss of workpiece capacity of the structure, not due to insufficient strength, but due to the inability of the compression rod to maintain the original linear equilibrium state.

It is recommended that the landlord look at the textbook to help understand these concepts.

1.Definition: All kinds of parts or components in mechanical equipment have certain functions, such as transmitting motion, force or energy, achieving specified actions, maintaining certain geometric shapes, and so on.

When a mechanical part loses its originally specified function under the action of load (including mechanical load, thermal load, corrosion and comprehensive load, etc.), it is called failure.

2.Common failures of mechanical parts are:

a) Integral fracture.

b) Excessive residual deformation.

c) Surface damage of parts.

4) Failure caused by disruption of normal working conditions.

In engineering, the loss of the function specified in the original design is called failure. Failure includes complete loss of intended function; Reduced functionality and serious impairment or hidden dangers, continued use will lose reliability and safety. The failure of mechanical parts is mainly (1) overall fracture, (2) excessive residual deformation, (3) surface damage of parts, and (4) failure caused by destruction of normal working conditions.

Before the 60s of the 20th century, it was generally believed that most equipment and components had a greater probability of failure over time and after a relatively stable period. Figure 1 depicts this failure mode as "Type A", which shows the likelihood of failure over time. Curiously, extensive studies in the aviation and military industries have found that time-related failures account for 20% of all failures.

This includes failure modes of types, A, B, and C. The failure modes of equipment or components, which are inherently random, are more prominent, accounting for about 80% of failures. These types include:

d, e and f. All failure mode types can be summarized as follows:

Mode A: When a device or component approaches its expected operating age, the likelihood of failure increases dramatically after a random period of failure.

Mode B: Commonly known as the "bath curve", this mode of failure is particularly relevant for electronic devices. Initially, there is a high probability of failure, but this probability gradually decreases and enters a plateau period, until the end of the life of the equipment or component, and the probability of failure increases.

Mode C: This mode shows the likelihood of equipment or component failure over time. This pattern may be the result of persistent fatigue.

Mode D: Except for the initial break-in period, during which the probability of failure is relatively low. This indicates that the likelihood of failure of the device or component is the same over its lifetime.

Mode E: The probability of failure of the device or component is the same over its lifetime. It's not about time.

Mode F: Compared with the "bath curve", this mode has a higher initial failure rate. After that, it is the same as the other two random modes.

Failure mode refers to a comprehensive term for the entire failure process from the factors that cause failure, the failure mechanism, the failure development process to the arrival of the critical state of failure. The most common basic failure modes are:

1. Deformation. Loss of original shape, which can be local or global deformation, elastic, plastic or creep.

2. Wear and tear. Such as abrasive wear, fatigue wear, vibration wear.

3. Corrosion. Including local, uniform and crevice corrosion, pitting corrosion, chemical corrosion, electrochemical corrosion, stress corrosion, intergranular corrosion.

4. Fracture. There are overload fractures, low-stress brittleness caused by cracks, low-temperature brittleness, stress corrosion fractures, creep fractures, hydrogen damage fractures, etc.

5. Fatigue. In case of fatigue cracks, leaks or breaks.

A failure mode is when a system or subsystem or component does not fulfill its purpose or function, and it is always defined in such language that the output measurement results related to the functionality of the vehicle, subsystem or component deviate from the customer's requirements.

The failure mode and failure mechanism are different, and it can be understood that a component can have a failure mode, such as the bolt moment 60n*m, which is the measurement result, and does not meet the requirements of 70n*m, which is the failure mode. The failure mechanism is the cause of the failure mode, which can be one or more reasons, such as the assembly torque is not in place, the bolt is unqualified resulting in baldness, the vibration is loose, etc., which is the failure mechanism of the failure mode bolt torque does not conform.

A potential failure mode is one in which the process may not meet the process requirements or design intent described in the Process Functional Requirements column.

It is a description of the non-conformity of the particular process. It may be a related cause of a potential failure mode in the next operation or a related consequence of a potential failure mode in the previous operation. However, in preparation.

What are the parts? For example, gears have wear, breakage, pitting, gluing, etc., after analyzing the possible failure modes of the parts you need, you can choose the most advantageous among the many parts in the case of comprehensive consideration of economy and applicability.

All parts have the potential to fail, and it is because of failure analysis that it is possible to increase the service life of the part. Failure analysis is not only about material selection

According to the summary of many failure analysis cases of Fantai Testing, parts are divided into mechanical parts and electronic parts

1. Common failures of mechanical parts belong to:

metallic non-metallic fractures;

discoloration, color aberration;

superficial abnormalities; deformation, poor fit;

Contaminants, inclusions;

cracking, aging, embrittlement;

All kinds of corrosion defects;

Poor welding; 2. Common failures of electronic components are:

Failure of resistance and capacitance inductance;

Semiconductor discrete device on-board failure;

Power module Lithium-ion battery failure.

PCB pcba connector cable failure;

Failure of mobile phone parts.

Only when failure analysis is done can quality control and cost control be done.

Potential failure mode and consequence analysis, or FMEA for short, analyzes the subsystems and parts that make up the product and each process one by one in the product design stage and process design stage, finds out all potential failure modes, and analyzes their possible consequences, so as to take necessary measures in advance;

Main tasks: risk assessment, analysis of the consequences and effects of potential failure modes, prevention and treatment of expected failures, their causes, consequences and impacts; Easier and less cost-effective modifications to products or processes to mitigate post-event crises; Ability to avoid or reduce the occurrence of these potential failures;

Benefits of Potential Failure Mode and Effects Analysis Techniques:

Point out the weaknesses of design reliability and propose countermeasures;

According to the required specifications, environmental conditions, etc., the experimental design or simulation analysis is used to improve the inappropriate design in real time and save unnecessary losses;

Effective implementation of FMEA can shorten development time and development costs;

In the early stage of the development of FMEA, design technology was considered, but later development, in addition to the use of design time, manufacturing engineering and inspection engineering can also be applied.

improve the quality, reliability and safety of our products;

Vance's Potential Failure Mode and Consequences Analysis Course;

A potential failure mode is one in which the process may not meet the process requirements or design intent described in the Process Functional Requirements column. It is a description of the non-conformity of the particular process. It could be the next step.

A related cause of a potential failure mode or a related consequence of a potential failure mode of the previous operation. However, when preparing the FMEA, it should be assumed that the received part material is correct.

When historical data indicates a defect in the quality of incoming parts, the FMEA team may make an exception.