The rock mass around an underground opening is subjected to a unique stress path that results in low radial
confinement and both tangential loading and unloading conditions near the wall. As a result, the rock
mass strength near underground excavations is controlled by failure mechanisms dominating at low confinement.
Hence, when constructing underground works in hard rock, two general scenarios are encountered:
(1) structurally controlled gravity-driven failures; and (2) stress-induced failure with spalling and
There is a vast multitude of materials with strongly differing properties. A
copper wire, for instance, can be bent easily into a new shape, whereas a
rubber band will snap back to its initial form after deformation, while the
attempt to bend a glass tube ends with fracture of the tube. The strongly
differing properties are reflected in the application of engineering materials –
you would neither want to build cars of glass nor rubber bridges. The multitude
of materials enables the engineer to select the best-suited one for any
Fracture mechanics is the field of mechanics concerned with the study of the propagation of cracks in materials. It uses methods of analytical solid mechanics to calculate the driving force on a crack and those of experimental solid mechanics to characterize the material's resistance to fracture.In modern materials science, fracture mechanics is an important tool in improving the mechanical performance of materials and components.
Tham khảo sách 'root cause failure analysis plant engineering maintenance series vibration fundamentals r. keith', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả
We are a group of dedicated material scientists each with 15–25 years of research
and development experience in the assembly and interconnect technologies of
electronics. Our experience in chemical and mechanical interfacial compatibility
between dissimilar materials dates back to the end of the 1980s. Since the early
1990s with the rise of the electronics industry in Finland, we focused our work
increasingly into the challenges of materials, assembly technologies and reliability
of portable electronics.
The book Renal Failure – The Facts consists of some facts about diagnosis,
etiopathogenis and treatment of acute and chronic renal failure. Acute, as well as
chronic renal failure is great medical problems and their treatment is a burden for the
budget of each government.
Acute kidney injury (AKI), previously termed acute renal failure, is a frequent clinical
condition in critically ill patients especially, in intensive care units (ICU). Its incidence
varies from 1-7 % of all hospitalized patients to 30-50 % of patients in ICU.
(BQ) Part 1 book "Drug and device selection in heart failure" presents the following contents: Renewed understanding of the pathophysiology of heart failure, new diuretics in heart failure, emerging role of aldosterone receptor blockers in heart failure, traditional mechanical support,...
(BQ) Part 2 book "Drug and device selection in heart failure" presents the following contents: Percutaneous mechanical support, cardiac resynchronization therapy, atrial arrhythmias in heart failure, heart transplantation, heart failure, ventricular tachyarrhythmias in patients with congestive heart failure,...
Reliability engineering and predictive maintenance have two major objectives: preventing
catastrophic failures of critical plant production systems and avoiding deviations
from acceptable performance levels that result in personal injury, environmental
impact, capacity loss, or poor product quality. Unfortunately, these events will occur
no matter how effective the reliability program. Therefore, a viable program also must
include a process for fully understanding and correcting the root causes that lead to
events having an impact on plant performance....
CHAPTER 18 FAILURE Jack Collins
Department of Mechanical Engineering Ohio State University Columbus, Ohio
Department of Mechanical Engineering Mississippi State University Starkville, Mississippi
18.1 18.2 18.3 18.4 18.5
CRITERIA OF FAILURE FAILUREMODES
377 378 18.6
ELASTIC DEFORMATION AND YIELDING 382 FRACTURE MECHANICS AND UNSTABLE CRACK GROWTH FATIGUE AND STRESS CONCENTRATION 18.5.1 Fatigue Loading and Laboratory Testing 18.5.2 The S-N-P Curves— A Basic Design Tool 18.5.3 Factors That Affect S-N-P Curves 18.5.
CMOS interview questions.
1/ What is latch up?
Latch-up pertains to a failure mechanism wherein a parasitic thyristor (such as a parasitic silicon controlled rectifier, or SCR) is inadvertently created within a circuit, causing a high amount of current to continuously flow through it once it is accidentally triggered or turned on. Depending on the circuits involved, the amount of current flow produced by this mechanism can be large enough to result in permanent destruction of the device due to electrical overstress (EOS)...
The authors use their decades of experience and draw upon real-world examples to demonstrate that the application of their techniques provides a basis for equipment management, uptime maximization, and reduced maintenance costs. The text explores reliability assessment techniques such as Failure Mode, Effect Analysis, and Fault Tree Analysis of commonly encountered rotating machinery. These are all highly effective techniques that the engineer can apply to maximize uptime and thereby maximize production and profitability.
The pathophysiology of cardiac arrhythmias is complex and the actions of drugs that are useful in stopping or controlling them may seem equally so. Nevertheless many patients with arrhythmias respond well to therapy with drugs and a working knowledge of their effects and indications pays dividends, for irregularity of the heart-beat is at least inconvenient and at worst fatal.The mechanisms by which the failing heart may be sustained are now better understood; carefully selected and monitored drugs can have a major impact on morbidity and mortality in this condition.