A comprehensive literature review of the pelvis and the lower extremity FE human models under quasi-static conditions

Finite Element Modeling (FEM) has become a vital tool in the automotive design and development processes. FEM of the human body is a technique capable of estimating parameters that are difficult to measure in experimental studies with the human body segments being modeled as complex and dynamic entities. Several studies have been dedicated to attain close-to-real FEMs of the human body (Pankoke and Siefert 2007; Amann, Huschenbeth et al. 2009; ESI 2010). The aim of this paper is to identify and appraise the state-of-the art models of the human body which incorporate detailed pelvis and/or lower extremity models. Six databases and search engines were used to obtain literature, and the search was limited to studies published in English since 2000. The initial search results identified 636 pelvis-related papers, 834 buttocks-related papers, 505 thigh-related papers, 927 femur-related papers, 2039 knee-related papers, 655 shank-related papers, 292 tibia-related papers, 110 fibula-related papers, 644 ankle-related papers, and 5660 foot-related papers. A refined search returned 100 pelvis-related papers, 45 buttocks-related papers, 65 thigh-related papers, 162 femur-related papers, 195 knee-related papers, 37 shank-related papers, 80 tibia-related papers, 30 fibula-related papers and 102 ankle-related papers and 246 foot-related papers. The refined literature list was further restricted by appraisal against a modified LOW appraisal criteria. Studies with unclear methodologies, with a focus on populations with pathology or with sport related dynamic motion modeling were excluded. The final literature list included fifteen models and each was assessed against the percentile the model represents, the gender the model was based on, the human body segment/segments included in the model, the sample size used to develop the model, the source of geometric/anthropometric values used to develop the model, the posture the model represents and the finite element solver used for the model. The results of this literature review provide indication of bias in the available models towards 50th percentile male modeling with a notable concentration on the pelvis, femur and buttocks segments.     

Impact of lightweight and conventional jackhammers on the operator

Jackhammer manufacturers have recently developed lightweight (45-60 lbs) jackhammers intended to reduce the required lifting and pushing forces during operation. However, the vibration characteristics of the lightweight jackhammers and their effect on muscle activity are currently unknown. The objective of this study was to compare the measured vibration and muscle activity between: (i) conventional (90 lb) and light weight (60 lb) jackhammers, (ii) different pavement type/thickness combinations, and (iii) pneumatic and hydraulic jackhammers. Five jackhammers were tested on 4 and 6 inch thick asphalt and concrete pavements by four experienced operators. Analysis of the results revealed that both weight classes averaged 9.7 m/s(2) at the 20 Hz weighted 1/3 octave band frequency, and the TLV of daily exposure for either weight class of jackhammer was less than 1.5 hours/per day. There was an approximately 33% difference in vibration measured on the hand of the operators due to pavement thickness, 30% due pavement type, and no difference due to power source. Conventional jackhammers overall produced higher muscle activity than lightweight jackhammers. Although selection of the correct jackhammer for the job involves many factors including pavement type and thickness, the results of this research can be used to assist in selecting the appropriate jackhammer.     

Casting an ergonomic eye on university libraries

Research in the field of Ergonomics of the Built Environment has been developed with a view to consolidating studies in this area, the objective of which is to provide evidence that the joint participation of users and designers on drawing up projects is important. In this context, the theme of this study is to investigate the interactions between users and the environment in a university library. To do so, well-established techniques from Ergonomics, Architecture and Environmental Psychology were used to make a functional and behavioral evaluation to identify the level of user satisfaction in six libraries in the various study centers of the Federal University of Pernambuco in Recife, northeast Brazil, so as to identify the strengths and also weaknesses in these spatial structures.     

Ergonomic basket design to reduce cumulative trauma disorders in tea leaf plucking operation

Work related musculoskeletal disorders are seen as an indicating parameter of occupational stress among the women workers engaged in tea leaf plucking operation. The hand plucking (no mechanized plucking is practiced in Assam) being a highly repetitive task requires forceful exertions to reach to the distant periphery of the tea bushes and mechanical compression (pressing against hard surfaces). Specifically it aggravates with awkward positions adopted. The current research addresses to minimize the risk factors associated with CTDs and to ascertain the role of ergonomic design development in improving the situation. Women workforce engaged in tea industry in Assam suffer from back, shoulder, arm and finger pains. Workers perform the activity for 440 minutes in the entire shift with one hour lunch break in between in the garden itself. An ergonomic investigation aiming at studying the strain index of plucking operation in tea industry was conducted. While performing the operation workers were found to assume unnatural posture which is static as well as highly dynamic with a load (tea leaf collecting basket up to weight of 30 kg when filled with plucked leaves) at back. With gradual increment of load and pain though the load is released intermittently the strain level found to remain at a high level. The total QEC scores found for plucking activity was 110 out of 138. To improve the situation and to reduce the work related upper limb disorder (WRULD) an ergonomically designed basket was conceived and trial results showed improvements. The newly designed plucking basket fits the back curvature of the workers well, which keeps the basket in place unlike the existing round basket. The new basket is light in weight having more leaf capacity. Significant reduction in energy expenditure and MSDs suffered was observed while using improved basket over existing basket.     

Designing for multiple global user populations: increasing resource allocation efficiency for greater sustainability

This paper proposes a method to identify opportunities for increasing the efficiency of raw material allocation decisions for products that are simultaneously targeted at multiple user populations around the world. The values of 24 body measures at certain key percentiles were used to estimate the best-fitting anthropometric distributions for female and male adults in nine national populations, which were selected to represent the diverse target markets multinational companies must design for. These distributions were then used to synthesize body measure data for combined populations with a 1:1 female:male ratio. An anthropometric range metric (ARM) was proposed for assessing the variation of these body measures across the populations. At any percentile, ARM values were calculated as the percentage difference between the highest and lowest anthropometric values across the considered user populations. Based on their magnitudes, plots of ARM values computed between the 1st and 99 th percentiles for each body measure were grouped into low, medium, and high categories. This classification of body measures was proposed as a means of selecting the most suitable strategies for designing raw material-efficient products. The findings in this study and the contributions of subsequent work along these lines are expected to help achieve greater efficiencies in resource allocation in global product development.     

Usability requirements for buildings: a case study on primary schools

This paper concerns an applied research aimed at applying the concept of usability, as derived form the standard ISO 9241/11, in the filed of building design, namely primary schools. Starting from the concept that space characteristics play a very relevant role in learning performances, the study presented here developed an original methodology for the assessment of effectiveness, efficiency and satisfaction of buildings hosting primary schools, in order to create a school environment better supporting users in their tasks. Research core is the framework of usability requirements and their related markers, indicators and technical specification that has been formulated in order to check compliance of urban area, building, rooms and architectural details with users needs. Therefore, a detailed task analysis of pupils and teacher tasks has been carried out and two questionnaires addressed to a significant users panel have been formulated for satisfaction survey. Lastly, a matrix for an overall reading of gathered data has been set-up and criteria for usability assessment based on that data has been defined. The whole study has been developed within the case study of a primary school in the Naples city centre, whose contents and results are discussed.     

Screening of risk from patient manual handling with MAPO method

International standards highlight the steps required by risk assessment and involving first hazard identification, then risk evaluation and finally, if necessary, risk assessment. To check approach appropriateness to "risk evaluation" from manual patient handling through MAPO, a cross study was carried out in view of checking relationship between this new risk assessment model and occurrence of acute low back pain. After proper training the MAPO screening method was assessed in 31 wards, 411 exposed subjects of geriatric hospitals. At the same time health data were collected on occurrence of low back pain episodes during the last year both in the exposed subjects' group and the external reference group (n?237). Risk and clinical assessment data were tutored and checked by EPM research unit. The logistic analysis was used as a method to evaluate the relationship between risk index and acute low back pain. Investigating relationship between acute low back pain episodes and levels of MAPO screening index, carried out only with the people exposed who claimed to work for at least 30 hours per week (n = 178), showed definitely positive trends. The study results indicate that MAPO screening may represent a useful tool to estimate the risk from manual handling patients.     

An ergonomic approach to improve work conditions of older employees in social housing

French companies are legally required to develop action plans to improve employment and work conditions for older workers ("plans seniors"). These plans contain measures oriented towards recruiting, career evolution, skills developme1nt, knowledge transmission and improvement of work conditions. A tool for assessing work situations experienced by council buildings caretakers ("gardiens") was used in such a plan on behalf of the main agency of council housing in Paris, and we developed. This assessment tool was developed after ergonomic work analysis on a sample of 36 older caretakers (age > 57 y.o). The technical inspectors in charge of technical interventions on buildings and managing caretakers were trained to use the assessment tool and apply it to all caretakers aged 50 and over.     

Manual flying skills under the influence of performance shaping factors

This paper describes an experimental study investigating pilots' manual flying skills. In today's line oriented flight training, basic flying skills are neglected frequently. So, the study examines the manual flying skills of commercial airline pilots under the influence of several performance shaping factors like training, practice or fatigue in a landing scenario. The landing phase shows a disproportionate high percentage of aircraft accidents and it is typically flown by hand. The study is to be undertaken with randomly selected pilots in a full motion flight simulator to ensure a high validity of the results.     

The perception of pleasantness in a product of collective use: the bus shelter

This article presents a study on the identification of a setting whose arrangement of attributes could lead to the perception of pleasantness of a bus shelter: a product that should welcome people while waiting for the bus. Two different bus shelters typologies in the city of Porto Alegre, state of Rio Grande do Sul, Brazil, were evaluated, where four attributes were under consideration. The relation between the shelters subject of the study and the surroundings was significant for defining the attributes. The setting with curve shaped cover, bench, rear wall, and surrounding vegetation was considered the most pleasant one. The seats and the rear wall were associated with the practical function of the product while the curve shaped cover and the surrounding vegetation were associated with the aesthetical function according to the participant users.