Applied Mechanics and Materials Vols. 592-594

Abstract: The leather manufacturing industry consists of several small-scale enterprises. Continuous efforts are made to improve the occupational safety of the workforce and productivity of these enterprises. In this manuscript, one of the important steps in pre-tanning process of leather manufacturing i.e., fleshing process is considered for a detailed study. The motion study identified that proper synchronization of movements by the workers would result in 18% reduction in the total number of movements. Time study revealed that proper implementation of the suggestions made in this manuscript would reduce the number of flips required for completing the fleshing process from 4 to 3 thereby saving approximately 7 seconds in the fleshing process per skin. This study therefore represents one of the first efforts to take a comprehensive look at productivity, ergonomics and safety of pre-tanning processes in Indian leather industry.

Abstract: The complex hospital environment requires special attention to ensure healthy indoor air quality (IAQ). It is necessary to protect to patient and healthcare workers against hospital acquired infections and occupational diseases. In a hospital environment, there is a trend of high concentrations of harmful micro-organisms. From an infection control perspective, the primary objective of hospital design is to place the patient at no risk of infection during hospitalization. Many people consider that hospitals are generally clean and free from pathogens which are actually not true. Hospitals are having very complex environment that require effective ventilation for comfort of patients & control from infections. Intensive care represents the highest level of continuing patient care and treatment. Therefore a turbulent airflow study has been performed in Intensive Care Unit (ICU) of hospital. The present investigation stresses preventing airborne infections, protecting the doctor and other patient in ICU, using Computational Fluid Dynamics (CFD) software FLUENT. In which, Navier Stokes and energy equations in three-dimensional co-ordinates have been solved by control volume method. The SIMPLE algorithms are used to solve these equations. Steady state, k-ε turbulence model and incompressible flow of a constant property fluid have been considered. The tracking of massless contaminated particle (infection) has also been carried out by simulation. It is observed that stagnant zone of the room is not healthy for the patients as well as doctor. Therefore suitable ventilation arrangement must be provided for healthy environment in the hospital.

Abstract: Redundancy allocation (RA) is one of the important approaches to improve system reliability by incorporating generally s-identical and s-independent components. However in the presence of common cause failures (CCF), a rarely studied problem as Redundancy optimization, the optimized system reliability may be adversely affected. In this paper the effect of CCF on Reliability Optimization using Redundancy Allocation has been expedited. The paper is implemented in two steps. Step1 involves obtaining the optimized solution of the problem using existing techniques. In the next step, modifications are done to compute optimized system reliability under CCF. The optimized reliability expression is modified to depict the effect of CCF. The work is extended to complex network analysis & implicit method has been used to do this work. The adverse effect of CCF on system reliability has also been demonstrated quantitatively with the help of example.

Abstract: The present investigation deals with different Ergonomical features, especially the humans – machines interaction and the problems associated with it. Attempts were made to acquire anthropometric data of the workers engaged in one of the gear manufacturing and assembling industry located at Coimbatore. Various angular movements exerted with respect to the wrist, forearm and upper arm of the worker on different equipments while pushing and pulling and lifting and carrying tasks were recorded to analyze the various working postures and problems associated with it.The analysis was carried out for two different trolleys which were used in their work place. The problems were identified and suggestion was given to industry. A redesigned trolley based on Ergonomic principles helped to alleviate the problems of the workers.

Abstract: Manual Material Handling (MMH) during maintenance activities poses strain to employees and at times it results in injuries. This type of work entails lifting, bending and twisting which can cause great strain to the human body if done improperly. A paradigm shift has taken place in Ergonomics from the narrow to a wide approach dealing with physiological, psychological, technological and organizational aspects of human work environment. This paper analyses the MMH hazards during the replacement of jaw bits in Electrically Operated Tong (EOT) crane in Hot Rolling Mill. Ergonomics risk factors were estimated using Rapid Entire Body Assessment risk assessment (REBA) tool. Based on the analysis, suitable engineering improvement called Lift - Assist Device was developed to reduce extreme range of motion while lifting, moving and inserting and found to be satisfactory.

Abstract: This paper provides guidance to key techniques and methods used in the EDM process industry for identifying and documenting environment, safety, and health (ESH) hazards and theircontrols.This is first time that the brainstorming method “what-if” analysis,one of the well-known process hazard analysis (PHA) techniques, is used to predict hazards in electrical discharge machining (EDM) processes. This technique analyzes potential causes and consequences of fires, explosions, releases of toxic or flammable chemicals and major spills of hazardous chemicals, and focuses on fluid system, machining system, electrical & instrumentation system, utilities, human actions and external factors that might impact the process. This analysis helped to identify conditions that can lead to an accident situation and recommendations are givento overcome the risks of these situations. An exhaustive analysis in the EDM process to identify and analyze hazards is presented in this paper and control recommendations are provided to overcome the risks of these hazards.

Abstract: Emission of toxic substances is the major occupational and environmental problem associated with this process. These emissions may cause adverse health effects to the operators and has the direct impact on the environment. The present investigation was conducted to study together the environmental and machining aspects of EDM process. The work aims to investigate the emission and machining parameters in EDM process using different workpiece material viz; like aluminum, mild steel and AISI-D3 tool steel with EDM 30 as a dielectric fluid and brass as a electrode. The results showed that the aluminium workpiece material gave a higher emission rate and MRR compared with mild steel and AISI D3 tool steel due to the low melting and boiling temperature. Among the process parameters, peak current and pulse duration was found to strongly affect the emission and performance aspects.

Abstract: Cost reduction, light weighting, quality and safety are the basis for all design and development of automobile component manufacturing. Low cost with high quality components can be produced by proper material selection, material cost, production volume, manufacturing process. This paper investigates the existing metallic bonnet with a new low cost and light weight composite bonnet. Fibers such as glass and jute along with matrixes of polyester and epoxy resin are selected for part fabrication. Using reverse engineering process design is extracted from original metallic bonnet and is redesigned for FRP application. Hand lay-up and VARTM manufacturing process are compared to fabricate FRP bonnet. Important factors that involve in bonnet under real time damages are impact of child head-form during accident is analyzed as per Euro-NCAP standard. From the result VARTM based glass/ polyester composite is found to be a better candidate for fabrication. Keywords: Predestrain safety, Reverse enginneering, hand layup, VARTM, Analysis.

Abstract: Automotive Seat Recliner is a mechanism that enables seat back rest to move forward and rearward about the pivot point of seat. An upgraded model of recliner with optimized dimensions is modeled so that the effort applied to unlock the mechanism reduces. The modeled Recliner was analyzed in LS Dyna to obtain the input data for fatigue calculations. Coffin Manson fatigue criterion is used to obtain results, which matches the experimental results undergone in lab.

Abstract: Structural failure of aircraft wings due to nucleation and propagation of cracks is one of the main reasons for failure of aged aircrafts. Reported studies on aircraft failures indicate that the main cause of wing failure is due to fatigue cracks which nucleate from the wing root region. Thus, determination of residual life of the cracked wing structure using fracture mechanics approach becomes important. In the present work an attempt has been made to estimate the SIF of single and multiple cracks in an aircraft wing subjected to lift force. Crack depth ratios ranging between 0.1 and 0.4 and aspect ratios of 0.6 and 1.0 have been considered. Single and multiple cracks are introduced at the wing rib region and the lift force is applied at the bottom surface of the wing. Geometric correction factor (Y) is estimated with the additional consideration of mode II and mode III fracture. The effect of crack depth ratio and number of cracks on SIF is determined. Non symmetric SIF distribution is observed with increase of crack depth ratio. It is also noted that SIF values are always higher at the crack surface region compared to crack middle region irrespective of crack depth ratio.