Failure Analysis Methods in Industrial and Systems Engineering

docx

School

University of Florida *

*We aren’t endorsed by this school

Course

3246

Subject

Mechanical Engineering

Date

Apr 3, 2024

Type

docx

Pages

Uploaded by GrandJaguarMaster265

1 | P a g e F a i l u r e a n a l y s i s m e t h o d s i n M e c h E n g i n e e r i n g Failure Analysis Methods in Industrial and Systems Engineering ENC3246 University of Florida 10.14.2022

2 | P a g e F a i l u r e a n a l y s i s m e t h o d s i n M e c h E n g i n e e r i n g Failure analysis methods in Mech Engineering I. Common Types of failures in Mechanical engineering .............................................................. 3 A. Types of failures .............................................................................................................................. 3 B. Cause of failure ................................................................................................................................ 5 II. Failure Analysis methods ............................................................................................................. 6 C. Preventative methods ..................................................................................................................... 6 1) Destructive and non-destructive methods ........................................................................................ 6 D. Forensic methods ............................................................................................................................. 7 1) Destructive and non-destructive ...................................................................................................... 7 2) Standards in mechanical engineering ............................................................................................... 7 III. Case Study ...................................................................................................................................... 8 E. Description ..................................................................................................................................... 8 F. Investigation .................................................................................................................................... 8 G. Recommendations ......................................................................................................................... 10 IV. References .................................................................................................................................... 11

3 | P a g e F a i l u r e a n a l y s i s m e t h o d s i n M e c h E n g i n e e r i n g I. Common Types of failures in Mechanical engineering Mechanical engineering is a branch of engineering specialized in processing energy forms and translate it into any desired motion. Engineers in this area perform from the general to the most specific tasks. Going through the design, manufacture and testing processes of devices that alter, transform, and use energy to create any type of motion.[1] Mechanical engineers are constantly exposed to failures in their products, which they try to predict and evade through, dynamics, statics, and mechanic of materials analysis. Although, currently through simulations with CAD programs, failures can be easier predicted and before the production and testing phase. A. Types of failures Mechanical engineers often find failures in their mechanical systems. Much of what is taught in engineering school needs to be put in practice. To maximize the accuracy of these devices, engineers must understand the basics of mechanics of mechanic materials, statics, and dynamics. They must be aware of the definitions and features of stress, deformation, slip, fracture, tension, and compression.[1] Which lead us to the four mechanical failures: Erosion, corrosion, Fatigue, and overload.[6] Mechanisms are commonly exposed to erosion, which implies a set of material removal through a series of impacts from a substance independent from the mechanism. Even while each collision only removes a tiny amount of material, the overall damage is frequently substantial. If you employ particles with sharp edges, erosion can get worse.[7] The effect might not be apparent until it is too late if the degraded surface is an internal surface that is not visible. In the worst-case scenario, a hole has already developed. Erosion is a common and dangerous failure that is exhaustingly analyzed by mechanical engineering. But, not considered by materials engineers in the design phase of a device.

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

4 | P a g e F a i l u r e a n a l y s i s m e t h o d s i n M e c h E n g i n e e r i n g Figure 1: Motor piece facing erosion Chemicals, take an important field of study on engineers, chemical compounds can create all types of reactions. Every surface of metallic constructions is vulnerable to corrosion. resulting from electrochemical or chemical processes.[3] While general attack corrosion is a known and foreseeable issue, it can also result in metal failure. Depending on the conditions under which the metal is being corroded, there are many ways to avoid corrosion. Techniques for preventing corrosion are: Environmental Modifications, Metal selection and surface conditions, Cathodic protection, Coating, Plating, corrosion inhibitors Mechanical engineers also face mechanic fatigue; a deficiency that happens when an item is put under recurrent or fluctuating loading but never reaches a level high enough to result in failure in a specific application and become an overload. Fatigue occurs when mechanisms are exposed to tensions, compressions or other type of external forces acting on them during prolonged times. A crack, which could have existed in the material when it was created or could have formed over time because of cyclic deformation around stress concentrations, is always the first sign of fatigue failure.

5 | P a g e F a i l u r e a n a l y s i s m e t h o d s i n M e c h E n g i n e e r i n g Figure 2: A piece that failed due to fatigue Engineers must consider loads; any mass will generate a force through gravity. These forces are often called “loads.” They can be classified into "permanent loads" and "accidental loads" depending on the length of the buildings' useful lives. Being the constant loads, those in play throughout the useful construction beam's wide range. While the accidental loads or overloads, are bodies or a group of bodies with a huge difference in mass that generates a force in a mechanism or structure. When the force becomes too large in magnitude, it breaks the static system and produces the failure called overload. B. Cause of failure Failure is a broad phrase used to describe when a machine, piece of equipment, or component fails while in use. When a component completely ceases to function, when it still functional but unable to perform the intended function for which it was created, designed, and manufactured, or when the component's deterioration has advanced to the point where it is no longer reliable or safe to use are some of the behaviors that can be considered failures.[8] Over time, the primary causes of failure have been identified as, design, Inadequate selection of material, faulty heat treatment, erroneous manufacturing, lack of maintenance and faulty machining. It is difficult to pinpoint the precise reason for a failure, but the issue can be fixed following a thorough analysis.

6 | P a g e F a i l u r e a n a l y s i s m e t h o d s i n M e c h E n g i n e e r i n g Figure 3: Forces causing failure 1 II. Failure Analysis methods C. Preventative methods It is crucial that the analyst design the investigation in accordance with the fundamental objective of any failure analysis investigation, which is to stop failures. All engineering failures, without exception, occur at the weakest link in the design-manufacturing-performance chain of a product. The ability to identify his weakest link and proposing corrective measures is the key to a successful failure analysis investigation.[1] 1) Destructive and non-destructive methods In mechanical engineering, professionals use testing methods to analyze the reaction of the pieces against external threats. Testing can divide two subsections; non-destructive and destructive methods; those that intend to destroy, are the destructive methods and consists in the use of invasive methods to find surface flaws or problems deep within a substance, quantitatively assess a property of an object or to Measure or inspect with the intention of endangering the component to analyze its behavior. Some of the destructive methods consists in applying some sorts of rays of currents to the object. On the other hand, non-destructive method is a collection of several inspection methods that can be applied separately or in combination to evaluate the quality and characteristics of a substance, component, or system. Some of the

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

7 | P a g e F a i l u r e a n a l y s i s m e t h o d s i n M e c h E n g i n e e r i n g non-destructive methods use by mechanical engineers are control by ultrasound, radiography, electromagnetic control, penetrating liquids, and visual inspection. Mechanical engineers use different methods to create a reaction and analyze it.[5] D. Forensic methods Failure analysis is the process of identifying the factors that lead to a vital part or component of a system failing, such as the material choice, design, application of the product, manufacturing processes, and failure mechanics inside the part. An examination of the failure's management processes is referred to as the root cause. The combination of the two creates a strong framework for the study of forensic engineering because failure analysis identifies the precise area of failure and root cause analysis identifies a comprehensive picture to ensure that it does not occur again. 1) Destructive and non-destructive When thinking of forensic methodologies, it is crucial to consider the reasons why other mechanical systems in the same field have failed. A company can more accurately calculate how much a stress, tension, or compression a mechanism of the same type can hold, to know how our device will behave . 2) Standards in mechanical engineering Standards are imposed by recognized organizations around the world, like (ASME). They intend to maintain the public's safety and the uniformity of products produced by professional, even such small pieces like screws and nuts must follows standards.[6] Standards on how to test and a construct a steel bride, its safety rules, material properties and exposure to recognized failure causes is a technique for ensuring that modules are functioning properly. All can be found in[6]. For a mechanical engineer, when building a bridge is important to understand all the standards, the properties of the materials using as well as all the rules in a static equilibrium system.

8 | P a g e F a i l u r e a n a l y s i s m e t h o d s i n M e c h E n g i n e e r i n g III. Case Study E. Description In this paper, we will examine the collapse that went on the Minneapolis I-35W Bridge, where there appeared to be a failure in the trusses. According to bystanders, the south end was impacted first. Then, the malfunction dispersed across the bridge. By means of a 1990 evaluation, it was declared to be "structurally weak”, and corrosion issues were mentioned. Unexpected out-of-plane distortion of the crossbeams and ensuing stress cracking were induced by the main trusses' connections to these crossbeams. Additionally, there was resistance to movement at the connection point bearings. F. Investigation The bridge was classified as hazardous terrain for driving in the winter months in 1996. Additionally, the Minnesota Department of Transportation, which was in charge of maintenance, put in place a system that prevented the creation of ice by spraying chemical compounds on the surface. It was shown that this technique might have accelerated foundation corrosion after the bridge fell. It should be mentioned that it was one of the first bridges of its kind to use this anti-ice technology in the United States. However, numerous studies on this bridge conducted before the collapse suggested that its structural integrity needed improvement. The forensic investigation's mechanical engineers concluded that the bridge was "structurally defective" and pointed to corrosion issues. They also identified more structural flaws.[4] It was also labeled as "structurally deficient" in 2005, per information found in the national inventory of federal bridges maintained by the US Department of Transportation. Like the previous inspection, this direction's 2006 inspection also ranked this bridge lower than average. Out of a potential 100 points, it received a score of 50. It should be noted that ratings below 80 denote a need for

9 | P a g e F a i l u r e a n a l y s i s m e t h o d s i n M e c h E n g i n e e r i n g rehabilitation, while ratings of 50 or lower denote a need for total replacement. Therefore, state and federal officials had grave concerns about the I-35 W bridge's structural integrity. Figure 4: Corrosion on the trusses 1 From a mechanical point of view, the failure due to corrosion was not the only reason. The metal sheet plaque reinforcing each of the joints in the trusses were erroneously elected. Since the thickness of the plaque was half of what the standards of a steel bridge of that magnitude is established. The plaque was around ¼” while the standards established by the US transportation recommends plaques of at least ½”. This action, the corrosion generated by the chemicals used on the bridge, and an overload created by construction vehicles as well as the enormous number of cars driving over the bridge because it was rush hours in the city, were responsible for this tragedy.

Your preview ends here

Eager to read complete document? Join bartleby learn and gain access to the full version

Access to all documents
Unlimited textbook solutions
24/7 expert homework help

10 | P a g e F a i l u r e a n a l y s i s m e t h o d s i n M e c h E n g i n e e r i n g Figure 5: compression on overload 1 G. Recommendations Thinking about evading this tragedy and save all the lives involved might be a little presumptuous. It is a fact that overload, corrosion and neglection of standards are failures that can be easily discarded in the testing phase and materials election. But the problem relies in that the circumstances coincided and that cannot be predicted. Even though the problem was matter of three failures coinciding, my recommendation is to check the plans and informs about the bridge before doing any change in the bridge, such as including a chemical that was never used before. Checking the standards established, so you know you will assure the public’s safety and control those overloads.

11 | P a g e F a i l u r e a n a l y s i s m e t h o d s i n M e c h E n g i n e e r i n g IV. References [1] Tawancy, Hani M., Nureddin Mohamed. Abbas, and Anwar. Ul-Hamid. Practical Engineering Failure Analysis. New York: M. Dekker, 2004. [2] Noon, R.K. (2000). Forensic Engineering Investigation (1st ed.). CRC Press. https://doi.org/10.1201/9781420041415 [3] Tawancy, H.M., Ul-Hamid, A., & Abbas, N.M. (2004). Practical Engineering Failure Analysis (1st ed.). CRC Press. https://doi.org/10.1201/9780203026298 [4] Mechanical Design Failure Analysis: With Failure Analysis System Software for the IBM PC, David G. Ullman. [5] H. M. Tawancy, H. M. Tawancy, A. Ul-Hamid, and N. M. Abbas, Practical Engineering Failure Analysis . New York, NY: Marcel Dekker, 2005. [6] Woo, Seongwoo. (2020). Mechanical System Failures. 10.1007/978-981-13-7236-0_7. [7] International Journal of Erosion Control Engineering. 東京 : 砂防学会 , n.d. [8] M. T. U. Michigan Technological University, “What is mechanical engineering?” Michigan Technological University , 13-May-2022. [Online]. Available: https://www.mtu.edu/mechanical/engineering/. [Accessed: 14-Oct-2022]. .