Office Desk And Chair Comfort Study Based On Physiological And Psychological Reaction

Sitting posture was the most widespread and popular ways in working.Office desks and chairs the most closely contact with users in sitting work. According to the survey, the height of keyboard, the unadjustable seat pan and adjustable seat pan were generally higher for majority usres. Using the unreasonable height of desks and chairs which do not match with human physiological size for a long time in working, the body fatigue and lower productivity would be appeared, related musculoskeletal disease of cervical vertebra and lumbar would be occurrence. Integrated structure of notebook computer resulted in notebook users maintain the compromise posture which was more head and neck flexion, more shoulder elevated angles.This posture make the ergonomics and furniture design put forward a new problem. In previous studies, the physiological and sychological reaction in the influence of furnitures function size on comfort was less studied. The function size of office desks and chairs fou using notebook computer were also less discussed.This makes the designer cannot be effectively understand the user’s psychological and physiological require, lead to certain blindness in furniture design.The posture habits of office workers and current use condition of office desks and chairs were analyzed through investigation and questionnaire survey. The analysis of the affect factors in sitting comfort was looked as the breakthrough poinpoint.The reaction of user’s psychological and physiological under different function size of desks and chairs was looked as the research subject. In this research,4different chairs and postures,4tabletop heights and2tasks conditions were used as the independent variables.3D posture capture system, body pressure measurement pad and surface electromyography were used to obtain head and neck flexion, scapula and arm postures, trapezius muscle, erector spinae, right anterior deltoid and wrist extensor muscle, and body pressure distribution experiment data. The following conclusions were obtained.1Under the condition of sitting posture with no actual task, the trapezius muscle activity was not significantly affected by posture and chair factors. There was no correlation between neck> shoulder discomfort and chair and posture.The result of body pressure distribution of seat surface stiffness characteristics was consistent with the actual material stiffness of seat surface, artificial leather and plywood was stiffer than breathable mesh cloth, than artificial leather and sponge, than mesh cloth sponges. 2In posture and chair experiment, the body part discomfort was ranked as:hips, thighs, waist, back and shoulders. The shoulder, back, waist and hip were significantly affected by posture. Chair factor was only impacted on the discomfort of waist, hip and thigh. Using of backrest can reduce the thorax and lumbar muscle activity and body partly discomfort.3Fuzzy comprehensive evaluation methods were applied to evaluate the comfort of office desks and chairs. The hierarchical structure of the fuzzy evaluation model was adopted. The evaluated factors were divided into four levels. Expert investigation method was used to evaluate index weight. The weighted sum calculation model was used to calculate the comprehensive evaluated comfort result of office desks and chairs. The comprehensive evaluated results of chairs’in physiological and psychological reaction have the same trend. Sequence of chair comfort in comprehensive evaluatied results were chair D> chair C> chair B> chair A. Chair D was the most comfortable chair in the4experimental chairs, Chair A was the most uncomfortable. The tabletop set as4cm higher than ellbow was optimum height for using notebook computer. The tabletop set as8cm higher than ellbow was optimum height for paper writing.